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Installing and Starting Emacs

1. Navigation Keys Moving by Character 39 40 44 47 50 52 4 59 6I 62 63 65 67 7O 74 76 78 82 83 84 86 86 86 go 92 93 95 95 96 Moving by Line 2 5 52 pa kaa ax ee 98 Moving by Word IOI Moving by S Expressions 107 Other Movement Commands 113 Serolling e s e sa eaei a eae oe a 118 Bookmarks and Registers 121 Selections and Regions 124 Selection Compatibility Modes 128 Setting the Mark oa 5 6 406 gece brik BO 131 Searching and Indexing gy we Roe eae 133 Isearch Incremental Search 2 133 Occur Print lines matching an expression 142 Imenu Jump to definitions 145 Helm Incremental Completion and Selection 147 IDO Interactively DO Things 153 Other Movement Commands 162 Conclusion oaoa a 164 The Theory of Editing 166 Killing and Yanking Text 2 167 Killing versus Deleting 169 Yanking Text 0 ercc6 hn oh ate Be a8 ek 173 Transposing Text oaoa aaa eee aes 174 c t Transpose Characters 175 m t Transpose Words 176 C M t Transpose S expressions 178 Other Transpose Commands 180 Filling and Commenting 181 Filing bys 2 2 on Ge Bis Gah sehen Beh te ge ae 181 Commenting eukd ee fee Get ao oe 183 Search and Replace 9a twee eek he 185 Case Foldines 4 ape pada ee ees 187 R
2. Repetition The Theory of Editing Missing Features Emacs does not support any kind of negative or positive look ahead or look behind except specific hard coded constructs More obscure regexp features like branch reset groups and so forth are also missing For most text editing this is usually not a huge problem One annoyance is the missing shorthand d for the digit class You must use 0 9 in lieu of d or the explicit class digit Emacs only features One area where Emacs s regexp engine does shine is its sup port for match constructs and Unicode support Constructs Description lt gt Matches beginning and end of word ie Aa Matches beginning and end of symbol scode Matches any character whose syntax table code is code Scode Matches any character whose syntax table code is not code Matching symbols and words with lt gt and _ lt _ gt is espe cially useful in programming for ad hoc re factoring The definition of a word and symbol is again down to Emacs s syntax table and thus major mode dependant Both s and s are very useful as you can match characters against a specific syntax class The naming of each class is The Theory of Editing really just a guideline as there is nothing stopping you from declaring that the number 9 belongs in the whitespace class if you are a major mode author Here is an abridged list of interesting syntax classes Whitespace characters In
3. Background Stipple m Inherit Hide Unused Attributes al j E E a zt 5 a a NI My personal foreground face color is OrangeRed But there s nothing stopping me from adding additional attributes as the figure above shows First Steps Ffont py home 1 font py All of 17 1 17 Python Indeed Emacs s renderer is quite advanced In the example above I ve changed font lock string face so it uses Hoefler Text and swash small caps Supported colors If you re using Emacs in a cut you are limited only by the color depth of the display and you are free to pick any color from the RGB color space I use named colors and to see a list of supported names you can type M x list colors display If you re on a Terminal you will be shown the colors supported by your Terminal usually only 16 or 256 Making the changes in the Customize ut isn t enough You have to apply the changes and optionally save them also If you don t save them the changes will not persist between Emacs sessions Pressing the aptly named Apply and Apply and Save do just that The Revert button is similar but has a few more options You only need Revert This Session s Cus tomizations if you re unhappy with the changes you have ap plied Keep in mind it will only revert the options you have in the current buffer not all the customizations made globally First Steps Always remember that you can revert
4. Shift selection similar to other editors C x C x Exchanges the point and mark and reactivates your last region The c x c x command called exchange point and mark is in teresting It reactivates the region from point which is your current location in the buffer and wherever the mark is then it swaps the point and mark positions This com mand is especially useful if you want to reactivate the last region or if you simply want to swap the position of mark and point Exchanging the point and mark is useful if you want to edit text near the mark or point or if you simply want to reactivate the region between your last mark and point Let s finish with a list of simple rules to remember 1 A region is a contiguous block bounded by the point and mark 2 You activate a region with c lt spc gt which sets the mark then activates the region if you use TMM and you should Pressing c lt spc gt again deactivates the region 3 An active region follows the point as you move around but breaks when you use a non movement command 4 The mark serves a dual purpose as a beacon you can re turn to with C u C lt SPC gt even one you set with c lt sPc gt The Theory of Movement Repeat calls to C u c lt sPc gt go further and further back the mark ring s Exchanging the point and mark with c x c x re activates the region and switches your point and mark around 6 Some Emacs commands don t care if the regi
5. The Way of Emacs The minibuffer is directly below the modeline and it is where errors and general information are shown UUU F3 scratch All L4 Lisp Interaction M x insert hello world In this case I have triggered Emacs s extended command func tionality indicated by the m x symbol a concept that I will talk about in the chapter on keys and I ve typed the com mand insert hello world into the m x prompt The echo area and the minibuffer share the same spot on the screen The minibuffer is nearly identical to a normal buffer you can use most of your editing commands and the one line minibuffer will expand to multiple lines if necessary It is how you communicate with Emacs if you want to search for a string you write the string you want to search for in the minibuffer It supports a variety of complex completion mechanisms to help you find what you need and is a tool you will use often The Point and Mark The point is just another word for the caret or cursor The Emacs documentation is rather inconsistent in its use of point or cursor you will see both Nevertheless the point itself is your current position in a buffer It s often represented par ticularly in Emacs s doc strings and documentation as but in this book I will use Jf to represent the point Each buffer tracks the position of the point separately so if you switch between buffers the location of each point is remem bered
6. All mark commands append to the existing selection if you already have a region active So if you want to mark two words in a row all you have to do is press M twice or com bine it with a numeric argument m 2 M Likewise you can reverse the direction by using the negative argument modifier The Theory of Movement The append functionality is particularly useful since your point remains static Emacs simply moves the mark from one position to the next That makes it easy to do topical edits like deleting the selection or executing a command against 1t In the chapter What Constitutes a Word I talked about syntax tables and how a major mode s syntax table affects movement commands A lot of mark commands are similar notably the m x mark word command m However some mark commands are overridden in some major modes so they work correctly for that particular mode For instance in reStructuredText the M x mark defun command bound to c M h will select a whole chapter this is sensible as there are no defuns a Lisp term for a function in a text file Not all major modes support M x mark defun but most modes supplied with Emacs do ultimately it s down to the author of the major mode to tell Emacs how to mark complex things like defuns Deactivating the region Remember you can deactivate the region with C lt SPC gt or C g Emacs s universal quit command I recommend you ignore c x C p marks the next page and fo
7. Contents Contents I Introduction Thank You Intended Audience What You ll Learn The Way of Emacs Guiding Philosophy Extensibility Important Conventions The Buffer The Window andthe Frame The Point and Mark 0 Killing Yanking and CUA emacs d init el and emacs Major Modes and Minor Modes First Steps Installing and Starting Emacs Starting Emacs 32 32 35 The Emacs Interface KEYS aem hele hod ote hee I ee Gees dee Caps Lock as Control M x Execute Extended Command Universal Arguments Discovering and Remembering Keys Configuring Emacs The Customize Interface Evaluating Elisp Code The Package Manager lt 0 alee 244 Color Themes Getting Help i ik sursa k iee YS Say oe cad The Info Manual Apropos lt 2 a aa sa eS E a Pee th The Describe System The Theory of Movement Whe asichien arena sete Slee nad G ach A c x C f Find file wie a ee Sea c x C s Save Buffer ahaaa aaa c x C c Exits Emacs c x b Switch Buffer c x k Kill Buffer 00 ESC ESC ESC Keyboard Escape Caf MIG Or n a cS da eho ed he Oe ek Window Management Working with Other Windows Frame Management geht lh oa ee Elemental Movement
8. Like the undo ring the mark ring contains all the marks you have placed in a buffer both directly using mark commands like c lt spc gt and indirectly from commands like m lt and m gt There is also the global mark ring for commands that work across buffer boundaries You can tell when the mark ring has changed be cause the text Mark set or a variation thereof ap pears in your echo area And because of this the command c lt spc gt will set the mark and with tmm enabled it also activates the region highlight ing when you move the point around That means if you just want to set the mark just so you can return to it later with C u C lt SPC gt you have to press C lt SPC gt C lt SPC gt once to set the mark and once more to deactivate the region Another gotcha is that things in Emacs that operate on regions text replace changing text to uppercase in a region and so on work just fine even if the region isn t activated as Emacs will not check if the region is active just that you are using TMM Here are the keys needed to activate selection and jump to the mark If you are new to Emacs feel free to use the shift selection keys until you are comfortable with Emacs s own selection mechanism The Theory of Movement Key Binding Purpose C lt SPC gt Sets the mark and toggles the region C u C lt SPC gt Jumps to the mark and repeated calls go further back the mark ring S lt left gt
9. and then type M x grep mode and watch as Emacs will highlight the match as though it were real The Theory of Movement output from grep This is a common pattern in Emacs re using the raw output from a command is a low tech but effective approach Other Movement Commands These movement commands are of limited use day to day for most Emacs users They are useful to know about and one or two of them worth incorporating into your work flow once you are comfortable using all the other commands in this chapter Key Binding Purpose M r C 1 C M 1 C x C n Cu C x C n M g M g M g TAB M g c Re positions the point to the top left middle left or bottom left Re centers the point to the middle top or bottom in the buffer Re positions the comment or definition so it is in view in the buffer Sets the goal column the horizontal position for the point Resets the goal column the horizontal position for the point Go to line Go to column Go to character position M r and c 1 are functionally similar m r will first move your point to the beginning of the line and then alternate between the top the middle and the bottom of the buffer All it does The Theory of Movement is toggle between those three locations c 1 is similar only it will scroll your window so the line point is on is re centered as the top middle or bottom c m 1 is similar only it will in telligently try and re position the window so the de
10. Emacs parlance The Theory of Movement Key Binding Purpose C x lt Scroll left C lt next gt Scroll left C lt prior gt Scroll right C x gt Scroll right If you edit a lot of text files with very long lines csv files perhaps you may find it useful to first disable word wrap ping or line truncation as it s known in Emacs with m x toggle truncate lines I would not bother memorizing the horizontal scrolling commands unless you really need them You can of course still use the mouse wheel to scroll though whether it works in the terminal or not will depend on your system Two more commands are useful for moving around namely the ability to go to the beginning and end of the buffer Key Binding Purpose M lt Move to the beginning of the buffer M gt Move to the end of the buffer When you move to the beginning or end of the buffer Emacs will place the mark an invisible location marker where you came from so you can return to your old posi tion For instance if you type M lt to jump to the beginning of the buffer you can type C u C lt SPC gt to go back c u as you remember is the universal argument in this case it sets a flag so that when you type c lt spc gt Emacs will interpret that The Theory of Movement to mean jump to the last mark The mark and its utility in Emacs is a topic I will discuss a little bit later Bookmarks and Registers Bookmarks in Emacs work identic
11. I would focus on memorizing the book mark commands as they are more likely something you use daily Selections and Regions Selecting text is a common action but in Emacs s info docu mentation and describe system it s referred to as the region As I mentioned in The Point and Mark a region boundary is made up of the point and the mark Other editors make little or no distinction between the be ginning and end of the region but in Emacs that distinction is rather important The region is always defined as the con tiguous block of text between the point and the mark For a visual demonstration try this in Emacs press C lt SPC gt In the echo area a message will appear saying Mark Set Now move your point around the buffer with the arrow keys or the other movement commands I introduced earlier and watch as the region changes because it is now activated Press C lt SPC gt again or the universal get out of trouble The Theory of Movement command C g to deactivate the region Note that the region is always defined as the mark to the point whether the point comes before the mark or not This functionality is thus similar to what you see in other editors when you hold down shift and move around with the arrow keys Therefore when you make visual selections you are using Emacs s Transient Mark Mode also known as TMM TMM came about much later in Emacs s history than you might think in fact it w
12. Like the mark commands there are many operations you can do Let s take a look at the basic ones first The Practicals of Emacs Keys Description Refreshes dired buffer Creates a sub directory Copy marked Renames moves marked chown marked chgrp marked chmod marked Deletes marked Deletes flagged Visits marked requires dired x mK USA OW OA Most of the keys above are self explanatory Just remember the difference between x and D if you want to delete files Copying or renaming between dired buffers You can copy or rename move files between two windows with dired buffers if you cus tomize the option dired dwim target Be careful you don t accidentally move files to an errant dired buffer you forgot you had open I ve made that mistake myself quite a few times Refreshing the dired buffer is necessary if the underlying file system changes Emacs will not by default track changes In part because itd be annoying if you were in the process of marking or otherwise altering the buffer Therefore you must forcibly refresh dired by typing g This command inci dentally is the universal refresh revert or rerun something key The Practicals of Emacs Dired X Some commands require dired x It s a package that for no good reason is not enabled by default that unfortunately you have to manually enable Add this to your init file for it to take effect require dired x With dired x installe
13. calling c h minside a vc status buffer yields a plethora of keys and documentation key binding C c Prefix Command TAB vc dir next directory C k vc dir kill line RET vc dir find file From then on it s a simple matter of clicking with ret or the mouse on each hyperlink you are interested in Working with Log Files Poring over log files is a common activity and there are tools in Emacs that makes it a snap to stay on top of them The Practicals of Emacs Keys Description c x c f Finds a file c x C r_ Finds a file in read only mode c x C q Toggles read only mode Opening a file is the first step but you may want to open it as read only to avoid accidentally saving it Likewise if the file mode makes it read only when you open it with C x c f Emacs will open it in M x read only mode You can toggle it on and off with c x c q but if you lack write per missions you obviously cannot save the file if you change it even if you disabled read only mode The reason you may want to disable read only mode is so you can apply destruc tive changes to the buffer perhaps to flush or keep lines Keys Description M x flush lines Flushes lines matching a pattern M x keep lines Keeps only lines matching a pattern M s o List lines matching a pattern Alternatively a simple m s o Occur mode search might suf fice It s easy to suffer pattern blindness and miss things if you scroll through row after row of nearl
14. github com purcell emacs d e Bozhidar Batzov s Prelude https github com bbatsovw prelude Use the defaults Certainly an option but Emacs I would say is rather lacking out of the box You are expected to configure Emacs to your liking or use a starter kit For an editor that is so radically different from main stream editors the maintainers are surprisingly conser vative about changing the defaults for fear of upsetting the old guard who of all people should know how to configure Emacs LISP Emacs is powered by its own usp implementation called Emacs Lisp or just elisp Many are put off or intimidated by this esoteric language that s a shame because it s a practical and fun way to learn ts in an editor built up around the idea of tsp Every part of Emacs can be inspected evaluated or modified because the editor is approximately 95 percent The Way of Emacs elisp and 5 percent C code It s also a practical way to learn a radical paradigm that code and data are interchangeable and malleable that the language owing to its simple syntax is trivially extensible with macros Unfortunately there s no getting around learning elisp at some point In this book I will talk about the Customize in terface a dynamically generated interface of customizable options in Emacs However something as simple as rebind ing a key means you ll have to interact with elisp But it s not all bad Most of the problems you
15. has addi tional keys bound to it All these keys hidden away in the dusty depths of Emacs all haphazardly bound to all conceivable permutations of key board characters may seem like a strange thing particularly if you come from modal editors like Vim First Steps The legacy of a particular keyboard used in the early 80s is evident in the names Super Hyper and Meta Back then most Emacs keys were bound to a larger range of physical keyboard modifiers but when the keyboard maker and the business that made the machines the keyboards were plugged into went bust Emacs had to change with the times Instead of undoing the cornerstone of Emacs the developers shuffled the keys around and made them work on normal boring rc keyboards So you re probably thinking it s a daunting task indeed to memorize all those keys but you don t have to I memo rize what I use frequently as we are wont to do with our human brains and leave the rest for Emacs to remember for me Use Emacs s help system if you forget a particular key combination You can always append c h to a prefix key Configuring Emacs Tinkering with Emacs is every Emacs hacker s favorite pas time Go to Emacs meetups or talk to experienced Emacs hackers and the conversation will inevitably drift towards small changes and hacks they ve made to make their lives easier It s fun and rewarding knowing that if there s an aspect of your edit
16. it use the customize interface M x customize option RET cua mode My personal recommendation is to learn Emacs s own re gion commands and more on that shortly as Emacs was never designed around the idea of cua mode Having said that eliminating barriers to entry and this is something the Emacs maintainers are working on is more important in the shorter term for a new Emacs user 6There was one reason to use cua mode and that was for its rectangle mode functionality In Emacs 24 4 that functionality is now built in and does not require cua mode any more The Theory of Movement Setting the Mark I have shown you how to activate the mark interactively with the arrow keys s lt arrow key gt and c lt spc gt but Emacs has a host of mark commands that work on syntactic units which as you may recall from earlier are things like words s expressions and paragraphs Setting the mark with c lt sPc gt is useful but it is cumbersome to use You have to set the mark move to your desired lo cation and then run your command Worse it breaks your tempo If you want to make precise selections you are better off using Emacs s dedicated mark commands Key Binding Purpose M h Marks the next paragraph C x h Marks the whole buffer C M h Marks the next defun C x C p Marks the next page M Marks the next word C M lt SPC gt and C M Marks the next s expression C lt SPC gt C g Deactivates the region
17. loaded and the features in Emacs you have activated Emacs has a range of specialist apropos commands that you might find more suitable M x apropos The thermonuclear option This command will display all symbols that match a given pattern Useful if you re trying to track down both variables commands and functions relating to a pattern M x apropos command or C h a AsI explained above this com mand will list only the commands M x apropos documentation or C h d Searches just the doc umentation In Emacs parlance that means the doc string documentation string with which you can supply symbols Occasionally useful M x apropos library Lists all variables and functions defined in a library This command can be useful if you re in vestigating a new mode or package as it lists the all the functions and variables defined in it M x apropos user option Shows user options available through the Customize interface This is one way to First Steps get the symbol names of Customize options but if you re looking for ways to search the Customize interface you are better off using the Search box in the Customize interface as it lets you customize the matches as well I never use it M x apropos value Searches all symbols with a particular value If you re looking for a variable that holds a particular value this command may be of use to you A potential use is if I know the value of a variable but not the name or where it s
18. slower to use as you have to manually select each buffer on which to run occur Imenu Jump to definitions Imenu is a generic indexing framework for jumping to points of interest in a buffer A major mode author will write a snippet of elisp that generates a list of points of interest their name and where in the buffer they occur so when you invoke imenu with m x imenu you can jump to any one of them The Theory of Movement Most but not all major modes support imenu For program ming modes the most obvious points of interest are things like functions and class definitions other modes may make use of them as well such as mail programs or structured text modes like Markdown or reStructuredText Imenu is another tool in your toolbox for medium and long distance movement I find that I use it most when Iam not sure of where something is in a buffer for jumping to things I see on the screen Isearch or elemental movement commands might be better and faster Oddly imenu is not bound to any key at all To use it you must type M x imenu That is unfortunate as I think it has historically hampered its adoption since it is not bound to any known or accessible key As you will see as you explore Emacs yourself that isa common occurrence so common in fact that 20 year veterans still find new things in Emacs that they had never heard about before I bind imenu to m i That key is already in use however The existing co
19. to navigate if you re reading an info manual end to end That s equivalent to reading a book starting from a chapter moving through all the sub chapters sub sub chapters and so forth in the order they were laid out Everyday reading For everyday reading you want spc for brows ing and reading as it does what you want It thumbs through a page until it reaches the end Then it either picks the next sub node or the next chapter For browsing use and to cycle back and forth through nodes If instead you want to jump to the next or previous sibling node you should use n and p To go back or forward in his tory much like a browser use 1 and r The key u goes up one level to the parent taB cycles through the hyperlinks and RET opens them Most info manuals are also published in HTML versions on line so why use Emacs s own reader For one you can use Emacs s universal bookmark system and more on that later You can bookmark almost everything in Emacs info pages files directories and more The other advantage is that it s in Emacs so keeping the info manual in a split window next to you is particularly useful if you re reading Emacs s excel lent An Introduction to Programming in Emacs Lisp and writing code alongside it If you want to read up on a specific Emacs functionality you have to open the Emacs manual first To do this type c h i First Steps followed by m When prompted for
20. But that s fine too the kill ring is finite but larger than you would ever likely care about A near infinite kill ring that won t forget your past kills is a powerful feature if you choose to take advantage of it Forget the idea that your kill ring is precious it s not Marking is unnecessary for most operations that involve syntactic units It s far quicker to tap M d three times in a row to kill three words to the kill ring than mark them with m first and then kill with c w There are two exceptions e If you want to copy M w the region it s quicker to mark first and then copy e If you want to kill or copy odd shaped regions that don t conform to multiples of syntactic units Kill appending is a versatile and unique feature in Emacs I often find myself re factoring code or text and the ability to kill text with the intent on moving it somewhere else and maybe rewriting or massaging some existing code or text first before yanking with c y the text back Appending to the kill ring The Theory of Editing Occasionally you want to append a new kill to the existing one in the kill ring This often hap pens if you want to kill different parts of a buffer that are not one contiguous region or series of kill commands To do this first type c mM w and Emacs will tell you in the echo area that if the next command is a kill command it will append to the kill ring Think back to how often you hav
21. Caps Lock as Control One of the most important modifications you should make to your environment is rebinding your caps lock key to con trol You re going to use the control key a lot and to avoid the Emacs pinky I suggest you unbind your right control entirely and instead use caps lock Yes itll be an annoying transition but a worthwhile one that will incidentally serve you well outside of Emacs First Steps This change is necessary because on older keyboards the control key occupied the space now used by the caps lock key so reaching the left control key could be done without straining your left pinky On Windows I recommend you use SharpKeys On Ubuntu and Mac osx it s built in go to the Keyboard settings and change it If you re using another Linux distribution you may have to fiddle with xmodmap M x Execute Extended Command Only a small portion of available commands in Emacs are bound to actual keys Most are not they are rarely used and do not warrant a key binding or maybe you have explicitly overridden the key it was bound to leaving it unbound or perhaps you forgot its key binding In essence it s common that you want to run seldom used commands To do this press m x pronounced mex M x or meta x In your minibuffer a prompt will appear and you are free to input the name of a command you wish to run When Emacs users say something like run m x lunar phases to see the lunar phases of
22. Dired Files and Directories 254 Navigation oee e esa tee ee See i 257 Marking and Unmarking 257 Operations e Ss Foe BAS ot eM eer oe a 259 Working Across Directories 263 Shell Commands haa So eke eo 2 264 Compiling in Emacs 20 46 6 2 ass 266 Shells in Emacs o g 1 2e s are woe aces oe Ms 267 M x shell Shell Mode 268 M x ansi term Terminal Emulator 270 M x eshell Emacs s Shell 2 271 Conclusion 273 Other Resources 004 275 Chapter I Introduction Tm using Linux A library that emacs uses to communicate with Intel hardware Erwin emacs Freenode Thank You Thank you for purchasing Mastering Emacs This book has been a long time coming When I started my blog Master ing Emacs in 2010 it was at the recommendation of a good friend Lee who suggested that I share my thoughts on Emacs and work flow in Emacs At the time I had accrued in an org mode file titled blogideas org a large but random assortment of ideas and concepts that I d learned about and wished someone had taught me The end result of that file is the blog and now this book Special Thanks Introduction I would like to thank the following people for their encouragement advice suggestions and critiques Akira Kitada Alvaro Ramirez Arialdo Mar tini Bob Koss Catherine Mongrain Chandan Rajendra Christopher Lee Daniel Hannaske Edwin Ong Evan
23. I would not worry about memorizing them In some usp circles it is common to group things by pages and as Emacs has close ties to the Lisp community it comes with a battery of commands to interact with pages Key Binding Purpose x Moves forward one page c x Moves backward one page Discovering the page commands Here s one way to find page commands C h a for M x apropos command then search for page to find all commands ending with the word page The Theory of Movement Knowing how to ask Emacs the right questions using apropos or the describe system is the cor nerstone of Emacs mastery Scrolling Like the arrow keys the lt prior gt and lt next gt commands Pg Up and Pg Down respectively have their own Emacs equivalents but Emacs s scrolling mechanism is different enough that some people find it frustrating That s because Emacs will scroll by nearly full screens where a full screen is the number of lines visible in that window To help with continuity when you scroll Emacs will retain two or three lines as governed by the variable next sc reen context lines so you don t lose track of where you are Key Binding Purpose C v Scroll down one page M v Scroll up one page C M v Scroll down the other window C M S v Scroll up the other window c v and mM v work the same way as the navigational keys lt prior gt and lt next gt The odd ones out are the two commands that scroll th
24. Like I explained in Getting Help If you don t see a menu bar it should appear in both GUI and Terminal Emacs and you have made changes to Emacs s configuration for instance a starter kit or a colleague s init file you can show it by typ ing M x menu bar mode but you still need to track down the part of your configuration where it s hidden Once you re a legendary Emacs hacker you will naturally want to hide it as it takes up valuable screen real estate but until then I encourage you to use it Most major modes have their own menu bar entry as well improving the discover ability of the major mode I used the menu bar for a long time when I was starting out and it really helped me as I could focus on remembering important commands like nav igation and editing Key Binding Purpose C x C f Find open a file C x C s Save the buffer C x b Switch buffer C x k Kill close a buffer C x C b Display all open buffers C x C c Exits Emacs ESC ESC ESC Exits out of prompts regions prefix arguments and returns to just one window Gs Undo changes The Theory of Movement Key Binding Purpose F10 Activates the menu bar The key bindings above are all you need to get started Emacs will guess the right major mode when you open files based on its extension and if that fails by the content of the file and more or less work out of the box Aside from the key bindings above you can start editing and movi
25. about the actual core of Emacs yet movement editing and so forth because although that s obviously critical to mastering Emacs they are specific skills that you could with patience acquire by using Emacs s self documenting help systems Knowing how to get help is critical because Emacs knows best Your Emacs configuration will dif fer sometimes just a little bit other times a lot First Steps from other people s Emacs configurations Asking a question on the Internet will only give you general answers If you rebind keys only your Emacs knows what the keys are You will discover more of Emacs I have stumbled upon more cool features than I can count simply by explor ing maybe a time saving command hidden away in a major mode or a variable that changes the behavior of acommand I use frequently A lot of third party packages may not have an adequate user manual forcing you to read the source or investi gate the commands and variables exposed by the pack age It will help you solve problems I help people with Emacs questions all the time but I don t know everything what I do know is where to look and how to read the documentation It gives you confidence Not knowing how to do some thing in Emacs is normal but also confusing But being able to say that oh I don t know how to do this but I do know where I can look for help your confidence in Emacs will go up in step with your kno
26. ago Surprisingly Emacs ran on some incredibly old platforms until Emacs 23 1 released in July 2009 including the follow ing Tandem Integrity S2 Apollo SR 10 x the Acorn the Harris Night Hawk Series 1200 and Series 3000 and about another two or three dozen more obscure platforms Emacs does officially support the usual flavor of Bsps and Linux Mac osx ms pos and Microsoft Windows I will not go into too great a detail on how to do this in this book Emacs was made to be a cross platform but there are always some trade offs if you don t run them on Linux Mac osx in particular seems to attract a great deal of conflicting advice on how to best run Emacs the best advice I can offer is to try out a few different approaches and find one that fits you thttp www gnu org software emacs MACHINES First Steps Microsoft Windows Emacs releases official builds for Mi crosoft Windows on their official site Extracting and running the executable is all it takes Most external tool support will not work on Win dows Functionality like built in grep support requires the cnu coreutils to be present You can however run Emacs from Cygwin and get a Linux like envi ronment on Windows that way Alternatively the cross compiled Gnu Win32 project has almost every Linux command line program that runs natively on Windows Mac OSX One approach though there are several is to use an unofficial build of Emacs There is
27. balanced expressions like curly or square braces Other Movement Commands I consider moving by character line word and s expression to be the most important movement commands They have the greatest utility across a wide range of editing tasks specifically programming and text editing but there are some movement commands that are best suited for specific tasks and whether or not they are useful to you depends entirely on what you do Moving by Paragraph Key Binding Purpose M Move forward to end of paragraph M Move backward to start of paragraph The Theory of Movement The definition of a paragraph depends on who you ask and your personal style and Emacs tries to cater to most of them The paragraph commands themselves rely on a set of vari ables that define the beginning and end of a paragraph Variable Name Purpose paragraph start Defines the beginning ofa paragraph using a large regular expression paragraph separate Defines the paragraph separator as a regular expression use hard newlines Set by the command M x use hard newlines and defines whether a hard newline defines a paragraph I recommend you describe the variables using c h v to get a better picture of how Emacs s paragraph system works The paragraph start variable in particular is a jumble of regular expressions that tries to do everything for everyone By de fault when you use m and m Emacs will treat newline delimited bl
28. be interactive which is an Emacs term for a function that has additional properties associated with it rendering it usable through the execute extended command m x interface and key bindings First Steps So if you re a package author you have to choose if a particular function is accessible to the end user through the m x interface Marking it as in teractive will make it accessible to end users In other words if it s not interactive you cannot run it from M x nor can you bind it to a key Universal Arguments Some commands have alternate states and to access them you need to give them a universal argument also called a pre fix argument The universal argument is also known by its key binding c u When you prefix another key binding this includes m x by the way you re telling Emacs to modify the functionality of that command What happens next will de pend on the command you re invoking some have zero one or even more universal argument states If a command has N states you simply type c u up to N times The universal argument is shorthand for the number 4 If you type C u a Emacs will print aaaa on your screen If you type C u C u a Emacs will display 16 characters because 4 times 4 equals 16 Keep in mind that universal arguments on their own are totally inactive When you type them Emacs will much like a prefix key wait until you give it a follow up command and only then will Emacs apply the u
29. block characters like Python s or and in C and automatically re indents the current line The intended ef fect then is that in the course of normal editing your code is correctly indented TAB Indenting the Current Line When you press TAB Emacs usually calls indent for tab command a generic proxy command that either indents your code or attempts to TAB complete the word at the point Key and Command Description TAB Indents line using major mode s The Theory of Editing Key and Command Description indentation command M i Inserts spaces or tabs to next tab stop M x edit tab stops Edits tab stops Some major modes override the taB key and instead call their own specialized indent command one example is the C major mode However pressing TAB or M x indent for tab command will if its heuristic determines that it should indent call the indentation function stored in the variable indent line function The advantage here is the generic nature of indent for tab command it s just there to pass on the work to either a completion command or an indentation command The variable tab always indent governs Emacs s behavior when you press TaB Usually it just indents but it also has a completion mechanism though seldomly used Disabling tab characters If you dislike the use of tab characters and if you prefer whitespace customize the variable indent tabs mode Finally when Emacs indents
30. by word M b Move backward by word If you ve used other editors the equivalent arrow keys are C lt left gt and C lt right gt and as I mentioned earlier they are also available to you in Emacs In Emacs word movement is The Theory of Movement rather complex behind the scenes and the exact behavior of word movement is dictated by the major mode you re using What Constitutes a Word What is a word Simply thinking of it as a series of charac ters separated by whitespace is what most people think and therefore expect but in Emacs the truth is a lot more com plicated Mode writers in Emacs make assumptions about the nature of the text in the buffer What you would write in m x text mode is different and treated differently from what you d write in M x python mode So mode authors need a way of saying that in text mode the period is a sentence separator and an attribute separator in Python Indeed every character printable characters including Unicode code points are given a meaning by the mode author directly or indirectly in a registry that maps the characters to a particular syntactic meaning This registry is called a syntax table a concept that I will refer back to several times to help you understand how it affects movement and editing but is otherwise only of interest to elisp hackers and mode writers The syntax table keeps track of things like What characters are used for comm
31. commands Frame Management You can create frames what are called windows in other pro grams and window managers and you may prefer to do this if you use a tiling window manager or to take advan tage of multi monitor setups Note that frames also work in terminal Emacs The Theory of Movement The prefix key used for frames is c x 5 Like the prefix key for windows c x 4 the commands are mostly the same Key Binding Purpose Create a new frame Switch buffer in other frame Delete active frame Delete other frames f Finds a file in the other window Opens M x dired in the other window 0 Displays a buffer in the other window 1 CES a a Sa a E a wu noa ANF OTN Switching buffers with multiple frames is seamless if a buffer is visible it is displayed in a frame in a window Emacs will switch to the right frame where the buffer is already visible Whether you choose to use frames or not is up to you The mechanics of dealing with multiple frames is slightly awk ward in Emacs as all frames share the same Emacs session which is sometimes a blessing or a curse I find frames use ful with multi monitor setups but not so much elsewhere The usefulness of frames I find is limited by the already ex cellent tiling window management system present in Emacs My only recommendation is to try it out and see if frames fit your workflow The Theory of Movement Elemental Movement Navigation Keys The most e
32. dired that listing all of them is not possible I recommend you apply the usual exploratory approaches Apropos describing the mode listing keys bound to prefixes to discover the rest Alternatively you can try out my package Discover that adds descriptive popup menus to Emacs There are also mark commands that mark specific things The Practicals of Emacs Keys Description m Marks region u Unmarks region Marks files by regexp Marks files by extension t t Toggles marking c Changes mark The prefix key is full of mark commands Shown above are the four most practical ones for day to day use The region keys mark or unmark every dired item touched by an active region The regexp and extension mark commands are simi larly useful and you can use t to toggle invert the marks cis special It changes the mark symbol from old to new So you can change the default mark symbol to D and turn the marked files into files flagged for deletion However as deleting is practically the only thing you d want to do with flagged files there is a special command that deletes flagged files and another that deletes marked ones too Operations You can carry out actions or operations on either the ac tive item if there are no marked files in dired or the marked ones if there are When you operate on marked files Emacs will usually ask you to confirm the action and lists the affected files
33. expect Now look at what happens if we move the point to the end of the line and type M b to move backward one word Before Hello world After Hello Jworld The word command is smart enough to realize that al though a period is not a word character it should simply ignore it as there is a word immediately before the punctuation Typing m f after we type M b will not take us back to our original example Before Hello Jworld After Hello Worldff This reinforces my point that word commands are not sym metric That will take a bit of getting used to Emacs will generally ignore non word characters immediately following the point in the direction you are travelling For instance we skipped over the period because it was a non word char acter and it was the first character the point would encounter going backwards The reason for this behavior is simple if Emacs didn t do this then every non word character the word commands would encounter in both text and code would count as a word of its own and end the movement command Here is a more extreme example but one you may well encounter in source code The Theory of Movement print add_two num_table 10 j The point above is at the end of the line and if you type m b and move backward one word you end up right before 10 print add_two num_table f1e This is because as before Emacs ignores symbols and punctu ation if and only if it encounters them bef
34. for a manual about Emacs s version control is a good place to start 1 Open the M x info manual by typing c h i The Practicals of Emacs 2 Navigate to the Emacs hyperlink and open it 3 Search with c s for version or version control Lo and behold if you tap c s enough times eventually you ll come across the Version Control manual that way So reading the manual works well but not every feature has a manual And perhaps the chapters are buried in a sub sub sub chapter out of easy reach And third party packages almost never ship with info manuals Apropos for info manuals You can use the command m x info apropos with a search pattern and Emacs will crawl all known info manual pages looking for match ing patterns If you are unsure of where something is this command is a powerful tool Using Apropos In Apropos I listed all the many ways of querying Emacs s documentation system using apropos One of those apropos commands will search the doc string the documentation string accompanying most variables and functions in Emacs and list the matching function or variable Searching Emacs s documentation strings is the most scattered ap proach to finding things you are literally searching plain text documentation To do this use c h d which is the apropos command that searches documentation Namespacing in Emacs Lisp The Practicals of Emacs Emacs Lisp unlike other lisps lacks namespacing There is
35. for templating as it comes with a large array of snip pets for many major modes and Hippie Expand since it s a great productivity booster Both Tempo and Skeletons are not worth learning today un less you have a specific reason to Abbrev is useful but only suitable for word replacements as it lacks the facilities of the more advanced text expansion tools I talked about above Autoinsert is also useful but it is again a package I would save for later When you have integrated YASnippet and Hippie Expand into your workflow you can add Abbrev and Autoin sert if you feel you need them Most never bother with either even though they are useful Abbrev Abbrev is the perfect tool for auto correct style features in word processors I use it to replace common misspellings and to replace words like resume with r sum However it is un questionably the wrong tool for the job if you want to use it for more advanced things such as complex text expansions you would use in software development Part of what makes abbrev effective is that it is simple it expands words without visual distractions in fact I rarely notice that it corrects words The Theory of Editing Key Binding Description Adds mode specific abbrev Adds global abbrev Adds mode specific inverse abbrev Adds global inverse abbrev H eA e uv oo ov o a When you add an abbrev with c x a g or C x a 1 Emacs will look at the word before point and use that as
36. history C M i TAB complete search string against previous search ring C s C s Begins Isearch against last search string C r C r Begins backward Isearch against last search string The first two should be self explanatory by now as they are universally available in all Emacs completions but the third one warrants a closer look TAB completion in Emacs In Emacs c M i is another TAB completion mechanism not unlike the one you see when you press TAB in the M x prompt In modes that sup port it and do not forget when you run Isearch The Theory of Movement you are essentially interacting with a mode the command is typically bound to complete symbol a generic completion mechanism that looks at the text at point and tries to complete it against a known set of completions In Isearch s case press ing c M i will also trigger the completion engine but a different one built for Isearch given its spe cialized nature but this time it ll compare your Isearch search string against your search history Try it out Searching for strings at point is such a common occurrence that there are dedicated commands to help you do just that Isearch Key Binding Purpose C w Add word at point to search string C M y Add character at point to search string M s C e Add rest of line at point to search string Emacs 24 4 or later C y Yank paste from clipboard to search string Emacs 24 4 or l
37. it is hard but the reward is well worth it The Theory of Movement Forward and Backward List Two more useful navigational aids are the sibling commands of c mM d and c M p because they move to the next or the previous list expression in the same nested level Key Binding Purpose C M n Move forward to the next list C M p Move backward to the previous list For instance here s what happens when you type C M n re peatedly ce 5 2 10 10 5 2 ff 10 10 5 2 i 10 10 5 2 10 10 ff As you can see it moves from one expression to the next and this includes the beginning and end of the balanced expression Typing C M n again yields an error we have reached the end of balanced expressions at this nested level If we type C M u to move up the list ic 5 2 10 10 The Theory of Movement Now we move out of the nested expression and into its par ent A subsequent call to c m n takes us to the end of the balanced expression 5 2 10 10 f For tsr the commands are invaluable Nested parentheses indicate hierarchy so utsp hackers require an efficient set of tools to move up down and around balanced expressions For all other programming languages the utility depends entirely on how frequently you encounter balanced expres sions In most languages like C Java Python or JavaScript they are very useful it s an elegant way of moving between some
38. it mean and how can you leverage that aspect to discover more about Emacs or answer questions you have about particular features I will show you what I do when I have to learn how to use a new mode or feature in Emacs and how you can use the self documenting nature of Emacs to find things for which you re looking Movement How to move around in Emacs At first glance a simple thing to do but in Emacs there are many ways of going from where you are to where you need to go in the fewest possible keystrokes Moving around is probably half the battle for a developer and know ing how to do it quickly will make you more efficient Some of the things you ll learn moving by syntactic units and what exactly syntactic units are using win dows and buffers searching and indexing text select ing text and using the mark Editing As in the chapter on movement I will show you how to edit text using a variety of tools offered to you by Emacs This includes things like editing text by bal anced expressions words lines paragraphs creating keyboard macros to automate repetitive tasks search Introduction ing and replacing registers multi file editing abbre viations remote file editing and more Productivity Emacs can do more than just edit text and this chapter is only a taste of what attracts so many people to Emacs its tight integration with hundreds of exter nal tools I will whet your appetite and show you some of the more int
39. least until you re comfortable with Emacs s system Buffers are rarely killed that is closed when they are no The Theory of Movement longer needed most Emacs hackers will simply switch away to something else only to return to it when needed That may seem wasteful but each buffer aside from assorted metadata and the buffer s particular coding system is only slightly bigger than the byte size of the characters in it A typical Emacs session lasts weeks between restarts and most Emacs hackers have many hundreds of buffers running without issue No matter the task you re doing in Emacs you will need to contend with the notion of buffers and windows and how to handle them Thankfully that can be as easy or as complex depending on your expectations or how you want things set up The Basics By the way Have you re mapped Caps Lock to Control yet Read Caps Lock as Control to understand why this is so important Learning the basic key bindings to find and save files change buffers and the bare essentials of day to day use is the first step on the path to mastering Emacs However you re free to use the menu bar to do this until you have committed the keys to memory One important thing to note about the menu bar is that it won t be clickable in a terminal unless you re using Emacs 24 4 or later Instead you must press F10 to activate and navigate the menu bar with the keyboard The Theory of Movement Note
40. like so emacs nw There s a host of command line switches you can pass to Emacs but you only need four to get started Switch Purpose help Display the help nw Forces Emacs to run in terminal mode q Do not load an init file such as init e1 Q Does not load the site wide startup file your init file nor X resources If Emacs is giving you error messages when you start it you can use q to prevent your init file from loading If that fixes the errors then you have a broken init file and should take 7The site wide file is a global settings file like your own init file First Steps steps to remedy that revert to an older version comment out code until it works or ask for help The Emacs binary follows the usual command line conven tions emacs switches filel file2 The Emacs way is to keep it running and do all your edit ing in a dedicated Emacs instance Emacs will typically start slower than other editors as it has a lot more packages and features as it s designed for long running sessions and not quick edits Emacs Client Server So how do you deal with situations where you re whiling away at the command line but have to edit a file Maybe you re writing an email from the command line or writing a commit message you d want to use Emacs and ideally the same instance of Emacs you already have running The answer ignoring the fact that Emacs has first class support for b
41. line it will remove blank lines ahead of the point Unlike the previous rule c x c o removes all blank lines Lines with only whitespace and tabs are also removed This is useful in languages where you often leave tabs or whitespace characters alone on empty lines C M o is a niche command that you won t use day to day Un like c o that inserts a newline after the point called opening a line c M o does the same but it maintains the column offset for the text Consider the difference between c o and C M o All the world s a stage fand all the The Theory of Editing After C o All the world s a stage fj and all the Now consider the original example but using c M o instead All the world s a stage fj and all the Note that the point remains in its original position Finally the m command does the opposite of c o and c m o it adjoins the current line the point is on with the one right above That is particularly useful if you want to collapse sen tences into one large paragraph or join multi line function arguments into one line m is clever enough to trim whitespace when you join two lines together That is to say Emacs will trim whitespace so that at least zero or one remain depending on whether the line you are adjoining has text on it or not For blank lines all whitespace is trimmed and for lines with text all but one space is trimmed Fill prefix Typing c M o with a fill prefix active w
42. mnemonic and bound to what you could call prime key real estate easy to reach and type keys They work exactly the same way other word commands in Emacs work and they respect the same syntax table rules as the forward word mark word kill word and transpose words commands do Both digit arguments and negative arguments work as you would expect Like the other word based commands I rec ommend you commit these to memory Forget memoriz ing the region commands Unless you do a lot of region based casing you are far more likely to change case word by word Maintaining your tempo when you use them is important as you will typically use them as you write M M u will upper case the last word you wrote for instance and M b M M u will move back one word and uppercase the word before that And of course you should not release meta between keystrokes So with your thumb on the left meta key your other fingers are free to type b u Consider this sentence I want to insert a full stop and capi talize the next word Bey how are you The Theory of Editing After typing M f to move forward a word to insert a full stop and M c to capitalize the next word Hey Howl are you Likewise here I finished typing an identifier but it should be uppercase because it points to a string constant print greeting_string f In most major modes _ is either punctuation or a symbol so it breaks the word ergo it would
43. movement com mands and the power of elisp in a buffer that is simultane The Practicals of Emacs ously used for more traditional things like text editing but now also for far more advanced and specialized things like interacting with bash And because both extremes share a common ground the buffer you don t have to re learn an entirely new system no more fretting with hand selecting text in a terminal emulator with a mouse just to copy it into your text editor or web browser In Emacs it is all text and all the movement and editing commands you are familiar with work exactly the same here M x shell Shell Mode Shell mode in Emacs calls out to an external program such as bash on Linux or cmd exe on Windows and either redi rects stdin stdout and stderr on Windows or through a pseudo terminal on Linux so you can interact with the un derlying shell through Emacs Because Emacs redirects 1 o you gain all the benefits and downsides that go with that however For instance you cannot use your shell s native TaB completion mechanism In stead you have to use Emacs s own which is more powerful in some respects The flip side to the coin is that a shell mode buffer is entirely text you can edit and delete output from commands and you can kill and yank text to and from the buffer with ease That makes shell mode flexible but polar izing Programs like top and man don t work at all or if they do
44. multi hops connecting to a remote host through interme diate hosts An example is if you have to access an internal server but first have to connect through a public server for added security another is if you have to log in as one user but then have to call out to sudo to edit a file as root on a remote server Let s start out with the simpler case of requesting sudo access to etc fstab sudo root localhost etc fstab As you can see the syntax is identical to a normal remote TRAMP connection only we re using sudo and we are con necting locally You can usually omit root as TRAMP is clever The Practicals of Emacs enough to guess it s root Keep in mind that this file is tech nically remote in the TRAMP sense so the usual rules about default directory apply Opening files with c x c f in a re mote buffer will open other files as sudo Multi hopping in Tramp is usually done by customizing tramp default proxies alist but I find it a bit fiddly the ad hoc syntax is much easier ssh homer powerplant sudo powerplant root salary txt The example above connects to powerplant as homer Then an other connection invokes sudo and opens root salary txt as a sudo d user It is very important that you repeat the host name in the sudo string or it will not work As before remote files obey the same rules as earlier Commands like M x she11 will give you a root shell on powerplant if invoked from the salary fil
45. no more errors When macro recording is in progress you will see in your modeline the word Def When you finish recording you can play it back immediately by typing c x e or F4 Recorded macros have their own macro ring much like the kill ring undo ring and history rings That means you won t have to worry about accidentally overriding a recorded macro if you start a new one They are never truly lost unless you exit Emacs but you can explicitly save them to disk You can also pass the universal argument and digit argu ments to the macro commands Key Binding Description C u F3 Starts recording but appends to the last macro The Theory of Editing Key Binding Description C u F4 Plays the second macro in the ring numeric F3 Starts recording but sets counter to numeric numeric F4 Plays last macro numeric times So c u and the digit arguments do different things Numeric in this case means numbers such as C u 10 or M 10 Appending to the last macro c u F3 is occasionally useful but passing a numeric argument to F4 is very useful since re playing the macro a set number of times is a frequent thing indeed so much so that passing digit c F4 or C u F4 for instance will run the macro over and over again until it terminates with an error such as reaching the end of a buffer or when a command in the macro triggers an error Advanced Commands There is an entire prefix key group c x C k dedicated
46. no separation of concerns using mod ules or namespaces in Emacs In practice it s not a huge deal there are bigger fish to fry but it does mean that informally packages in Emacs prefix their symbols functions variables etc so they don t clash Examples include python for the Python major mode apropos for apropos related commands and so on Nevertheless if you search for version control with c h d the first result is this vc mode Function Version Control minor mode This minor mode is automatically activated whenever you visit a file under control of one of the revision control systems in vc handled backends VC commands are globally reachable under the prefix C x v We now have a lead The vc mode is vc mode However we want the prefix it uses and it is vc Knowing that vc s prefix is vc We Can Use M x apropos command bound to c h a to find all the vc commands The Practicals of Emacs M x apropos command RET Then at the prompt enter Search for a command word list or regexp vc Emacs returns the results of the Apropos search vc annotate C x v g Display the edit history of the current FILE using colors vc check headers M x RET Check if the current file has any headers in it vc clear context M x RET Clear all cached file properties fesse You ll see a list of commands along with a brief description and the key binding if any A quick browse through r
47. of the hundreds of supported coding systems you are using hence why c h C lt RET gt is a sure fire way to see what it is The Theory of Movement Line endings When you open a file Emacs will determine the line endings used If the file uses pos line endings then they are preserved when you open the file and when you save it Likewise for unrx and pre osx Mac intosh encodings The modeline will tell you what line ending you are using U helloworld c 92 of 5k The first character u as explained above indicates the coding system The means it s unrx style line endings For Dos it would say Dos and Mac for Macintoshes c x C s Save Buffer In The Buffer I explained that in Emacs a buffer need not be a file on your file system but it could be a transient buffer used for things like network 1 o or even just a scratch file for processing text So what that means in practice is that you can save any buffer in Emacs even internal ones like a help or a network 1 o buffer When you ask Emacs to save a buffer it will save it to the file associated with the buffer if and only if the buffer has a filename associated or ask you for a name if there isn t one The latter instance will typically happen if you re saving a buffer that does not yet have a file assigned to it maybe it s a temporary buffer or even the output from a help command The Theory of Movement Writing a buffer to a file If you wa
48. of the major mode treat as three distinct words written like and this instead of just one Command Purpose M x subword mode Minor mode that treats CamelCase as distinct words M x superword mode Minor mode that treats snake_case as one word Global minor modes There are global modes available for both and you can enable them by typing M x customize option global subword mode M x customize option global superword mode When you enable m x subword mode you enable special move ment transpose and kill commands that operate on each in dividual capitalized word in Camelcase If you write a lot of code in languages that use CamelCase you ll find subword mode useful The Theory of Movement Glasses mode There is a whimsical minor mode m x glasses mode that visually it does not alter your buffer text separates CamelCase words into Camel_Case The superword command M x superword mode is similar but does the opposite it rewires symbols which usually but not always include the underscore so they re considered part of a word Note that this command is not perfect Major mode authors decide what syntax class a character like _ or should fall under and if they don t set a character like _ to be a symbol the command will not work Moving by S Expressions Perhaps the most useful but underused feature in Emacs is the ability to move by s expression or just sexp The cryp tic name deserves an ex
49. on buffers and not strings as I mentioned in The Buffer That greatly lowers the usefulness of this feature as you not only have to find a function that does what you want but you have to find one that works on The Theory of Editing strings When I have needed this feature I have inevitably resorted to writing my own specialized functions that transform the text the way I want But that assumes a certain level of flu ency in elisp My advice would be to use Emacs s keyboard macros a topic I will cover shortly as they are far more suited for complex editing tasks Changing Case Case changing capitalizing text or turning it into lower or uppercase is a common occurrence in both code and text There are two groups of commands that alter the casing re gion commands and word commands Region Commands Description C x C u Uppercases the region C x C 1 Lowercases the region M x upcase initials region Capitalizes the region There is not much to say about the first two When your region is active you can uppercase or lowercase the region Capitalizing the region actually means capitalizing every word in the region not just the first word in a sentence line or paragraph The case commands that act on words are far more interest ing The Theory of Editing Key Binding Description M c Capitalizes the next word M u Uppercases the next word M 1 Lowercases the next word First of all they are
50. or parts of a file s path stored in the variable auto mode alist For instance if you open etc passwd Emacs will de tect this and open the file with etc passwd generic mode major mode If the filename ends with zip Emacs will instead open the file in archive mode Although the different heuristics may look complicated the good news is the work is done for you Emacs s major mode The Theory of Movement detection is rather sophisticated and it will almost always pick the right thing for you Coding Systems and Line Endings Emacs applies two other important heuristics you should know about coding systems and line endings Coding systems Emacs has excellent Unicode support type C h h to see it demonstrated including transpar ently reading and writing between different coding systems bidirectional right to left script support keyboard input method switching and more To see the coding system in use for the current buffer you can type C h C lt RET gt Emacs will display a lot of in formation including all the coding systems associated with the buffer but for files they are almost always set to the same coding system The modeline will also give you a rough idea U helloworld c 92 of 5k The first character u means the buffer helloworld c has a multi byte coding system If it said 1 it would typically be part 1 of any number of 1so character en codings The exact mnemonic will depend on which
51. point the mark is more than what it seems It serves as a boundary for the region yes but it is also a beacon you can use to return to from other parts in the buffer The mark is typically invisible Killing Yanking and CUA The first and perhaps most abhorrent to beginners de viation from de facto user interface standards is Emacs s clip board system Cut copy and paste are known almost univer sally to most as Ctr1 x or Shift Del Ctrl c or Ctrl Ins and Ctrl v or Shift Ins respectively In Emacs the keys and the terminology differ greatly killing is cutting yanking is pasting and copying is awkwardly known as saving to the kill ring or just copy informally The reasons as before are historical Most of the keys and terminology stem from IBM s Common User Access cua and Apple But the cua was introduced in 1987 many years after Emacs had settled on its own terminology and stan dards In Selection Compatibility Modes I will explain how you can switch to modern clipboard keys with certain caveats and why you shouldn t do that Instead I ll show you why Emacs s system is better for text editing 6http en wikipedia org wiki IBM_Common_User_Access The Way of Emacs emacs d init el and emacs A favorite pastime of Emacs users is sharing with other Emacs hackers little snippets of code or customizations that make their lives easier Historically these settings were kept in a f
52. prefilled suggestion The Theory of Editing Complex align using regexp s The regexp matches in a capturing group zero or more whitespace characters The reason it does this is because a file you want to align may have plenty of whitespace already perhaps you aligned it a short while ago and because you changed the text it is now misaligned so Emacs has to match and capture existing whitespace around the character you want to align and then re align it correctly When you use novice mode Emacs automatically inserts that regexp before the character you want to align by that means any whitespace before your alignment character is removed so even in novice mode the whitespace capturing group is there So to columnate on you must add to the beginning or end of the existing regexp Where you put it alters the alignment outcome Put it before and Emacs will insert spacing to columnate after the You may want to do this with a symbol like If you don t it will look like this Fooooo Bar Bizz Buzz Put it after and Emacs will insert spacing to columnate be fore the You may want to do this with a symbol like If you don t it will look like this The Theory of Editing Foobar Widget 15 00 Fizz Buzz 10 00 So for this you want to answer the prompt like so Complex align using regexp s Next pick the default answer Parenthesis group to modif
53. rather poor it offers basic TAB completion and some fuzzy matching but little else I recommend you try mo mode a built in feature that gives you fuzzy file completion I use it and couldn t live without it indeed most Emacs users employ it or some other form of fast completion To enable it type M x ido mode and then try C x b or C x C f again You can enable it permanently by customizing the option ido mode M x customize option RET ido mode RET You can also improve 1bo s fuzzy matching by enabling flex matching M x customize option RET ido enable flex matching RET The Theory of Movement And you can customize many more features by running m x customize group ido For further reading on this subject I recommend you read Introduction to IDO mode c x k Kill Buffer Killing a buffer in Emacs means closing it You don t have to kill buffers you don t use It s perfectly normal to let them sit in the background until you need them again Normally se rious Emacs users have hundreds or even thousands of open buffers at a time ESC ESC ESC Keyboard Escape The click your heels three times key If you re stuck somewhere or want to go back to normal then pressing ESC ESC ESC will probably solve your problems All windows are deleted meaning they re hidden from view prompts are exited out of special buffers are hidden prefix arguments are cancelled and recursive editing levels are unw
54. re likely to encounter have already been solved by someone else a long time ago it s a simple matter of searching the Internet for a solution to your problems Despite the relative unpopularity of elisp versus more mod ern languages like Python Ruby and JavaScript I doubt Emacs would have had the same power of extensibility if a more traditional imperative object oriented language had been used What makes tsp such a fantastic language is that source code and data structures are intrinsically one and the same the Lisp source code you read as a human is almost identical to how the code is manipulated as a data structure by tsp the distinction between the questions What is data and What is code are nil The data as code the macro system and the ability to ad vise arbitrary functions meaning you can modify the be havior of existing code without copying and modifying the original give you an unprecedented ability to alter Emacs to suit your needs What would in most software projects be considered code smells or poor architecture is actually a major benefit in Emacs you can hook replace or alter exist The Way of Emacs ing routines in Emacs to suit your needs without rewriting large swathes of someone else s source code This book will not teach elisp in any great detail Emacs has a built in elisp introduction and I highly recommend it if you are curious and honestly you sho
55. s _ alter Isearch so word and symbol delimiters like and freely match other delimiters For instance consider a buffer with this text gYou can check by typing M x emacs version The Theory of Movement this is a hyphenated string Searching for hyphenated string with c s alone will not yield a match but if you re run the search with c s and then toggle word search mode with m s w it will Word search is especially useful in languages where you want to match two successive words separated by possibly unknown word delimiting characters like this C example mystruct gt foo 42 Searching for mystruct foo will match the element access above if you toggle word search with m s w Some of the toggles and commands I have covered are so frequent that they have their own global keybindings Key Binding Purpose M s w Isearch forward for word M s _ Isearch forward for symbol M s Isearch forward for symbol at point Emacs 24 4 or later You should recognize the first two as they are the same key bindings available to you inside Isearch itself The last one M s is only available as a global key binding It begins a forward Isearch for the symbol at point This is useful if you have the point on an identifier in your source code that you want to search for elsewhere The Theory of Movement Learn Isearch It is a powerful search tool in its own right but it also lets you move around the buffer quickly by sea
56. search string you want to match Emacs will also cleverly suggest a file type based on gt your current buffer s file type and Emacs will also look at the current symbol your point is on and ask if you want to search for that That is convenient because you often find yourself on or near an identifier or word you want to search for and in that case you can just type M x rgrep and type RET twice to accept the defaults Grep Guesswork The high level commands particularly rgrep do a lot of clever behind the scenes guesswork when it calls out to find First of all Emacs runs on any number of platforms and it has to work consistently on all of them Not all platforms come with xargs so Emacs will check for this and use find s The Theory of Movement own exec switch instead Quoting and escaping characters in strings vary on platforms and shells and Emacs needs to work with all of them Windows note On Windows there is already a program called find To override the default choice in Emacs you should add this to your init file making sure to change C gnuwin32 bin to the location of GNU find and then restart Emacs setenv PATH concat C gnuwin32 bin path separator getenv PATH Another arrow in Emacs s quiver is the ability to automati cally pass negative matches to find For instance you don t want to search source control directories like git or trash files that yield false positive
57. separately The Way of Emacs Note In Emacs we talk a lot about a current buffer which can mean two things only one of which is interesting to us at the present and that is whichever buffer has the point the other case is ba sically the same but involves programmatically changing the buffer in elisp A buffer that has the point is the current buffer because it is the one you write and move around in Only one buffer can ever be the current buffer at a time and it is this buffer that has the point The point in Emacs has more utility than just acting as a visual marker for where characters you type end up on the screen It is also one part of a duo called the point and mark The point and mark represents the boundary for a region which is a contiguous block of text usually in the current buffer In other editors it is called the selection or the highlight Most editors don t have specific names for the beginning and end of a region but in Emacs we do and in Selections and Regions I will talk more about the reason Tip Historically Emacs did not show you the visible region on the screen but instead you had to men tally visualize it Emacs has supported visual re gions for a very long time now called the tran sient mark mode or just TMM It is enabled by de fault Surprisingly there s some value in not us ing TMM at all but I will talk about that much later The Way of Emacs But like the
58. take two presses to go backward with m b to put the point at the beginning of greeting string A simpler way instead of calling m u twice to uppercase it is to use the digit and negative arguments M M 2 M u print GREETING STRING With a bit of practice you will be able to do it so quickly and intuitively that it will take less than a second or two to do The other benefit is that it does not move your point you are free to continue writing It may not seem like much time saved but these things add up The case commands also work with non Latin characters since Emacs maps most Unicode characters to their correct Unicode categories In practical terms that means Emacs knows when it encounters a lowercase or uppercase charac ter The Theory of Editing Greek a p spy gt ABYAEOF Danish abcd gt ABCDAGA Unicode categories Try M x describe categories to seea full list of all Unicode categories Learn these commands and learn how to use them with a negative argument also It s acommon typo to mess up word casing as you re writing text or code deleting the word and starting over or manually fixing your mistake is time consuming Counting Things There s no need to call out to we when you want to count things as Emacs is perfectly capable of doing that too Command Description M x count lines region Counts number of lines in the region M x count matches Counts number of patterns that match in a reg
59. talked about in Emacs as an Op erating System the very fabric of Emacs is modifiable and extensible through elisp So the only way to truly under stand what happens in Emacs is to ask it simple but true And asking Emacs is what all Emacs masters do Whether it is to check what a key is bound to or what exactly a com mand does it is part and parcel of what defines Emacs mastery Yes knowledge of elisp is a big help but it is not an absolute requirement 273 Conclusion Throughout this book I have written about features and functions and my own personal views on what is worth fo cusing on and what isn t That is the truly practical overar ching aspect to this book The deeper lesson and what was ultimately the linchpin moment for me when I first started learning Emacs is understanding how to ask Emacs questions Not remembering a key or a command is perfectly natural especially when you re still learning but knowing that Emacs can tell you what it does even if you have heavily modified or altered your key bindings is what will ulti mately help you truly master Emacs Forgetting what c x r 1 does is immaterial when you can use C h k to find out and partially remembering what something does is also not important when you can append c h to any prefix key to describe all the keys bound to it The long term goal of any Emacs user is to reach a point where they can seek answers to questions they have by ask in
60. the commands frequently when I process text Keeping lines that match a pattern is useful for large log files when you want to say only show GET requests from a web server Joining and Splitting Lines Unlike the kill commands that act on lines c M lt backspace gt and c k these commands won t alter your kill ring They are also more specialized as they insert or remove lines with out moving your point Key Binding Description C o Inserts a blank line after point C x C o Deletes all blank lines after point C M o Splits a line after point keeping the indentation M Joins the line the point is on with the one above c o is useful when you want to insert a newline immediately The Theory of Editing after point Unlike RET your point will not follow onto the next line It will remain in its original position sometimes useful in text when you want to split a paragraph into two and not move the point with RET Deleting blank lines is a common action c x C o does just that but it obeys three rules Ignores your current line It will not remove the line the point is on even if it is empty That means if you call the command on a block of empty lines it will always leave exactly one empty line Remember this rule as it s a great way to keep a con sistent number of spacing between say paragraphs in text or class and function definitions in code Works ahead of the point So when you call it on a non empty
61. the end brace when you type C m f Once you start thinking about code in terms of balanced ex pressions you ll see them everywhere It s not just in LISP that you ll find them useful almost all major modes are full of balanced expressions and as an added bonus the s expr movement commands act like the word commands when you invoke them on unbalanced expressions such as reg ular text It s absolutely vital that you learn how to use these com mands Four more movement commands exist that work on balanced expressions but only brackets and not strings Down and Up List Key Binding Purpose C M d Move down into a list C M u Move up out of a list Like the s expression movement commands the list com mands were meant for Lisp but have found a life outside that language When you press c m d the point will jump into the nearest balanced expression of parentheses ahead of where the point currently is Before The Theory of Movement Bresult foo bar After result foo ffbar The point moves inside the nearest balanced expression To do this the point will jump an arbitrary distance and re peated calls will go deeper into nested structures and con versely c M u will go back up Like the word commands the list commands are not symmetric going up will take you up one level but leave your point at the opening character Before result foo bar fp After result foo barff Mo
62. the replace ment word that is and I get confused myself the word you want it expanded to and not the trigger word So to re place resume with r sum you would type r sum and place your point after the word and type say C x a g and enter resume When you press spc after typing resume Emacs will replace it with r sum The inverse commands do the opposite You type the word resume enter C x a i g answer r sum and Emacs will expand resume into r sum DAbbrev and Hippie Expand Hippie Expand is great It has an almost preternatural ability to expand the text at point into what you mean no mean feat when you consider how many expansions from which there possibly are to choose Before I talk about Hippie Expand let s talk about how you use DAbbrev its lesser cousin and the default dynamic ab breviation tool in Emacs The Theory of Editing Key Binding Description M Expands word at the point using M x dabbrev expand C M Expands as much as possible and shows a list of possible completions The key m is easy to type and repeated presses will cycle through the list of choices Repeat the command enough times and it will revert back to the original word And if there are many choices to choose from the c m command will attempt to complete as much as it can and display a list of completions if there is still more than one choice DAbbrev is not smart It looks at other words in your buffe
63. to GNU Emacs one component of the GNU Linux operating system macs Tutorial Learn basic keystroke commands Emacs Guided Tour Overview of Emacs features at gnu org View Emacs Manual View the Emacs manual using Info Absence of Warranty GNU Emacs comes with ABSOLUTELY NO WARRANTY Copying Conditions Conditions for redistributing and changing Emacs Ordering Manuals Purchasing printed copies of manuals To start OpenaFile Open Home Directory Customize Startup To quit a partially entered command type control g This is GNU Emacs 24 4 50 1 x86_64 unknown linux gnu GTK Version 3 10 8 of 2014 06 02 on mickey vb Copyright C 2014 Free Software Foundation Inc Auto save file lists were found If an Emacs session crashed recently type M x recover session RET to recover the files you were editing U GNU Emacs ALL LS Fundamental For information about GNU Emacs and the GNU system type C h C a When you first launch Emacs you re greeted with the splash screen It s probably one of the first things most Emacs hack ers disable along with the scroll bars the menu and tool bar Until you re comfortable with Emacs I would recommend you leave the ur elements enabled since they will provide you with a quick way to access common functionality that you may not remember how to do off hand although they take up valuable real estate on your screen First Steps If you re using Emacs in the Terminal you can still acces
64. transpose and once again without a negative argument to get the right side word to transpose The reality is a little more compli cated but not by much It s also an easy theory to test call m m f and m f from your original position making sure to move the point back to the original position between the calls and you will find the left and right edge of the words m t will transpose If Emacs s word movement behavior made no sense before I hope it makes a bit more sense now It s not to everyone s lik ing but it is consistent across movement kill and transpose It also works on prose Hello world After M t World Helloff c M t Transpose S expressions You can transpose s expressions balanced expressions with c m t and like word transposition with m t the mechanics are identical the same forward amp backward principles apply when the transposition function finds the left and right edges Consider the following piece of tsp code The Theory of Editing 2 ni 4 n Calling c m t on it will swap the two forms positions 4n 2 ni Like m t from before the concept is identical but the applica tion differs But c M t much like M x forward sexp c M as sumes the role of m x transpose word if there are no balanced expressions Hello world And after c m t it becomes World Helloff But consider what happens if we mix a balanced expression with a word He
65. your file system are another task for which Emacs is emi nently well suited Aside from editing local files the usual way and remote files using TRAMP you can manipulate di rectories and files using Emacs s directory editor dired The Practicals of Emacs To access dired you can do so in multiple ways From IDO mode You can type c d when finding files with C x C f to open a dired buffer in that file s current di rectory Asacommand The command m x dired opens a prompt that asks you for the dired location to open It defaults to default directory the directory the current buffer isin As with Tramp if the file is remote Emacs will ask you if you want a remote dired session Asa key bind The key binding c x d works identically to the command above The command c x 4 d does the same but in the other window When you open a dired buffer in Emacs you re greeted with a view that looks similar to this usr share dict total used in directory 2328 available 187646744 drwxr xr x 2 root root 4096 Feb 16 09 57 drwxr xr x 326 root root 12288 Mar 27 11 43 rw r r 1 root root 938848 Oct 23 2011 american english rw r r 1 root root 938969 Oct 23 2011 british english rw r r 1 root root 199 Jan 14 2014 select wordlist If you use the Linux command line its output should look familiar That is because Emacs in keeping with the spirit of other commands like m x grep simply augment the out put from existing comma
66. Misshula Friedrich Paetzke Gabriela Hajduk Gabriele Lana Greg Sieranski Holger Pirk John Mastro John Kitchin Jonas Enlund Konstantin Nazarenko Lee Cullip Luis Gerhorst Lukas Pukenis Manuel Uberti Marcin Borkowski Mark Kocera Matt Wilbur Matthew Daly Michael Reid Nanci Bonfim Oliver Martell Patrick Mosby Patrick Martin Sebastian Garcia Anderman Stephen Nelson Smith Steve Mayer Tariq Master Travis Jefferson Travis Hartwell Like a lot of people I was thrust into the world of Emacs without knowing anything about it in my case it was in my first year of University where the local computer soci ety was made up primarily of Vim users It was explained to me in no uncertain terms that you use Vim that s it Not wanting to be told what to do I picked the polar opposite of Vim and went with Emacs Emacs proved to be a stable and reliable editor in all those years but it was a tough one to get to know Despite the extensive user documentation it never helped me to learn and understand Emacs Introduction As it turns out Emacs is a philosophy or even a religion So the joke about the Church of Emacs is eerily accurate in many ways as you will find out in the next chapter Intended Audience It s a bit weird talking about the intended audience when you ve already bought the book on the subject But it bears mentioning anyway so no matter your Emacs skill level you will get something out o
67. That will list all commands that end with word Here s a subset of the output you would see if you ran that command Command Key Purpose ispell word M Check spelling of word under or before the cursor kill word M d Kill characters forward until encountering the end of a word left word C lt left gt Move point N words to the left to the right if N is negative mark word M Set mark arc words away from point As you can see you get the name of the command the keys bound to it if any and the purpose Emacs has certain nam ing conventions and once you re familiar with Emacs you will see certain patterns emerge For instance it s common to postfix a command with the syntactic unit or context it op erates on word for words window for windows and so on Hint Apropos can sort results by relevancy To enable this add setq apropos sort by scores t to your init file First Steps There s a wide range of apropos commands you can use to query Emacs apropos command is perhaps the most useful toa beginner And it ll let you search by pattern which is great if you only remember part of a command s name but not all of it It s also a fantastic way to accidentally discover new features in Emacs Giving apropos command the pattern to match everything yields approximately 8 000 commands that Emacs knows about this amount however will vary greatly depending on the number of packages you have
68. a menu item type Emacs for the Emacs manual or Emacs Lisp Intro for the introduc tion to elisp As always there is TaB completion You can also browse the master list of manuals and find the one you want to read You can look up the documentation for a command by typ ing C h F and at the prompt enter the name of a command Emacs will jump to the correct place in the info manual where the command is described Apropos Emacs has an extensive apropos system that works in much the same way as apropos does on the command line The apropos system is especially useful if you re not entirely sure what you re looking for There is a variety of niche commands that only search particular aspects of Emacs s self documenting internals Apropos is a useful tool to have in your toolbox It shines because you can narrow what you re looking for to a par ticular area If you re looking for a variable you can use the apropos system that searches variables if you are looking for commands you can search by command And all of apropos supports regular expressions The most common one bound to c h a ISM x apropos command apropos command shows all commands and just the commands not functions that match a given pattern For instance you might be on the hunt for commands that work on words but more on what a word actually means in What Constitutes a Word so entering c h a followed by First Steps word is a good place to start
69. about in Buffer Switching Alternatives no mode is a powerful minibuffer completion engine Helm and mo overlap in purpose and some prefer to use one to the exclu sion of the other most use both but for different purposes IDO is a distraction free target aware search Unlike Helm wo does not use a separate buffer and window to show completion matches Instead it completes in line in your minibuffer itself This is preferable for things like buffer switching and file finding as you roughly know where you re going and for what you are looking That is how I use mo mode and I think it s a great way to start out for almost everyone out there it is certainly a better choice than the default TaB based completion mechanism The Theory of Movement However Do fails when you re not entirely sure what you are looking for stepping through the matches in the minibuffer is tedious when all you want is an overview of everything that matches your query Helm is for in depth searching and completion Helm will open a transient buffer and window to display matches and that greatly increases visual clutter and distraction that is not in itself bad if you are unsure what you are looking for But if you know what you are doing for instance you are in buffer foobar txt and you want to open widgets c IDO is a better choice as you can seamlessly switch buffers and not suffer the visual overhead Indeed if you are a touch typist you wil
70. above universe answer 42 universe question What is The Answer In both cases I had my point on either line and typed m x align current and Emacs figured out which rule to apply Despite the usefulness of automatic alignment it is unlikely your scenario perfectly matches any of Emacs s alignment rules For all other instances you have to use Emacs s flexible M x align regexp and tell Emacs how you want your text aligned There are two modes of operation when you use M x align regexp novice mode which is what you see when you run the command and complex mode when you call it with c u The only situation wherein you are likely to truly use the complex mode is when you want to do multi column alignment on the same line Annoyingly that feature is not available in novice mode Consider the following text The Theory of Editing Cappuccino 2 00 Caramel Latte 2 30 Americano 3 50 Macchiato 4 00 To columnate the text and align the prices on the with m x align regexp Align regexp And the output Cappuccino 2 00 Caramel Latte 2 30 Americano 3 50 Macchiato 4 00 It gets harder if you want to align multiple columns Con sider this csv text Price Product Qty Sold 2 00 Cappuccino 289 2 30 Caramel Latte 109 3 50 Americano 530 4 08 Macchiato 20 To columnate all three columns you must use the complex mode So type C u M x align regexp The first thing you will notice is the
71. aces where commands act on functions Like the sentence and line commands the defun commands use C M as their modifier Key Binding Purpose C M a Move to beginning of defun C M e Move to end of defun The defun commands move to the logical beginning or end of the function point is in I must point out that function is re ally a rather loose term It doesn t have to be a function but in programming modes it s usually functions classes or both for other modes it might do other things in reStructured Text for instance it will jump to the beginning and end of a section or chapter Moving to the beginning of defun is really useful if you want to say quickly change the name or signature of a function ina programming language Consider the location of point int addtwo int x return x 2f Pressing c M a will take us to the beginning of defun addtwo The Theory of Movement int addtwo int x return x 2 Subsequent calls to c m a will take you further and further up the chain to a parent block perhaps or the top of the file if you are at the root Moving by Pages A page in Emacs is only tangentially related to the real life concept of a page In Emacs a page is anything delimited by the character defined in the variable page delimiter which by default is the control code L better known as the ascu control code form feed It is unlikely that you will ever use these commands so
72. acs is a major productivity booster as you ll soon see ack and ag If you prefer ack or ag to grep then head to the Emacs package manager where you will find Emacs friendly packages for both Emacs supports a large array of grep and grep derivative com mands None are bound to a key by default so you will have to call the commands directly with m x and later bind the ones you use frequently to keys Command Purpose M x grep Prompts for arguments to pass to grep M x grep find Prompts for arguments to pass to grep and find M x lgrep Prompts for query and glob pattern to search for with grep M x rgrep Prompts for query and glob pattern then recursively searches with grep and find M x rzgrep Like m x rgrep but searches compressed gzip files The Theory of Movement The grep commands fall into two categories Low level commands like m x grep and M x grep find They supply you with a suggested grep command string and all you have to do is add the search pattern and any additional options you require I don t use them frequently I usually want to search for a pattern in a group of files and these commands are too low level for that Occasionally I want to call grep with specific options and in that case I have no choice but to use M x grep or M x grep find High level commands like m x 1grep M x rgrep and M x rzgrep They hide the command string completely and instead ask you for the files you want to search and the
73. ake_upper_case hello world f The Theory of Editing After C M C M k s make_upper_case f The kill commands are useful but there are generalist clipboard equivalent commands in Emacs too Key Binding Kill Ring Purpose Clipboard C w Kill active region cut M w Copy to kill ring copy C M w Append kill Cay Yank last kill paste M y Cycle through kill ring replacing yanked text Killing versus Deleting This one crucial difference between killing and deleting trips up a lot of new Emacs users In most editors there is a clear delineation between clipboard commands that act solely and exclusively on the selected text and commands that delete text In Emacs all commands will with few excep tions like the two I mentioned above kill text straight to your kill ring If you are new to Emacs it will confuse you and maybe even infuriate you No other editor fiddles with your clipboard content unless you explicitly tell it to but Emacs does and it s a great feature once you get used to it Emacs s kill commands are best summarized with five simple rules The Theory of Editing Consecutive kills append to the kill ring All kill com mands append to the kill ring that is to say they append to the text in the kill ring if and only if the last command was also a kill command If you break the cycle by moving or writing or running a command the next kill command will create a new entry in th
74. ally to the ones in your web browser but with the notable exception of supporting a wider variety of sources That makes Emacs s bookmark ing system flexible enough for you to bookmark info pages files M x dired directories and info manual pages Because of Emacs s TRAMP system it is therefore also possible to book mark remote files for speedy access Bookmarks in Emacs are permanent meaning they are au tomatically saved to a bookmark file in emacs d called bookmarks Bookmark file The variable bookmark default file determines where Emacs stores your bookmarks The file is plain text elisp s expressions actually meaning it is possible edit it manually if you absolutely must or merge the files if you regularly add or remove bookmarks from multiple machines Key Binding Purpose C x rm Set a bookmark c x rl List bookmarks C x rb Jump to bookmark The Theory of Movement Bookmarks are a very efficient way of jumping to frequently used files or directories it is also useful if there are sections of Emacs s manual that you want to return to frequently And because of the unified nature of Emacs buffers the three are seamlessly stored and recalled from the same list of book marks Registers however are different they are the flip side of the coin where bookmarks are permanent registers are tran sient A register is a single character store and recall mecha nism for several types of data i
75. also Aquamacs but it differs from cnu Emacs quite a bit The topic itself is rather complex Some prefer using a package manager like homebrew and others do not Generally people who use homebrew often use the homebrew version of Emacs also Emacs Wiki s article on installing Emacs on Mac osx is a good place to start if you want to compile Emacs yourself Linux Emacs is almost always present in your distribution s package manager Some distros are slow to update to new minor releases which are rarely minor at all adding a lot of new functionality and bug fixes so it may be worth your while to build from source 2http ftp gnu org gnu emacs windows 3http www cygwin com 4http gnuwin32 sourceforge net shttp emacsformacosx com 6http www emacswiki org emacs EmacsForMacOS First Steps On Ubuntu it s as easy as apt get install emacs24 If you want to build your own version of Emacs from source I recommend you use apt get build dep emacs24 to build and install Emacs s dependencies From that point on it s easy to follow the usual configure make make install procedure Starting Emacs Starting Emacs is as simple as running emacs from the com mand line If you run the command from a window man ager then Emacs will launch as cur Emacs as opposed to Terminal Emacs where Emacs is running inside a terminal You can force Emacs to run in a terminal even in a window manager by giving it the argument nw
76. ame way you move or kill text Key Binding Purpose C t Transpose characters M t Transpose words C M t Transpose s expressions C x C t Transpose lines M x transpose paragraphs Transpose paragraphs M x transpose sentences Transpose sentences The Theory of Editing When you call a transpose command Emacs will first look at where the point is and depending on the exact transpose command you issued swap two syntactic units surrounding the point How Emacs defines a syntactic unit in this case is a bit compli cated as your major mode determines what a syntactic unit is Negative arguments also work so do digit arguments but not the way you would expect When you give a digit argu ment to a transpose command it will get the Nth unit ahead of the point unless you also give it a negative argument in that case it is the other way around and swap that unit with the one immediately before the point That is rarely useful c t Transpose Characters Transposing a character takes the character to the left and right of the point and swaps them alec After c t Balic Note that the point moved forward one character so you can repeat calls to c t to pull the character to the right BCA The Theory of Editing One important exception to this rule is when you are at the end of a line c t will swap the two characters to the left of the point BCA After C t BACH This asymmetry is a surprisingly useful way of fixi
77. and is Emacs s lossage If you ever want to turn actions you have completed but for got to record into a macro you can extract them from the lossage buffer with c x C k 1 and transform it into a macro Text Expansion There are several built in tools and just as many third party ones in Emacs that expand text All of them serve a slightly different purpose but the goal is to minimize typing and maximize automation Here are some of the ones available to you in Emacs Abbrev Expands abbreviations such as func into function on a per mode or global level A very simplistic expan sion mechanism its main advantage is that it silently whiles away as you type fixing typos or expanding abbreviations There is like a lot of Emacs s other fea tures little graphical ceremony no whirligig graphics or other visual clutter to distract you when it expands a keyboard in fact it s unlikely you ll notice at all unless you are looking for it You would typically use this for unambiguous correc tions such as correcting typos DAbbrev or dynamic abbreviations Similar to Abbrev but it expands the previous word by dynamically The Theory of Editing looking for things the word at point might expand into For instance typing func in a buffer where you have a lot of function definitions and DAbbrev will expand it to function automatically when you manually trigger the expansion mechanism Hippie expand A super char
78. and search amp replace The Theory of Editing Deleting Duplicates You can delete duplicate lines in Emacs and the best thing about it is unlike the command line utility unig the lines don t have to be adjacent for Emacs to detect duplicates That means you can delete duplicates without sorting the text Universal Argument Description Without Deletes first duplicate line C u Deletes last duplicate line C u C u Deletes only adjacent duplicates C u C u Cu Does not delete adjacent blank lines By default M x delete duplicate lines deletes the first dupli cate line it encounters starting from the top With a single universal argument it starts from the bottom and therefore deletes the last Flushing and Keeping Lines Sometimes you want to filter lines in a region by a pattern whether that is to flush lines that match a pattern or keep the ones that do Both commands act on the active region so it is common if you want to do this on a whole buffer to call c x h to select the entire buffer first Command Description M x flush lines Flushes deletes all lines in a region The Theory of Editing Command Description that match a pattern M x keep lines Keeps all lines in a region that match a pattern and removes all non matches Both commands accept a regexp pattern and any match ei ther flushes or keeps the line it is on and not the pattern itself for that use search amp replace I use
79. and you will as it is used everywhere in Emacs you ll wonder why you never learned it earlier Further Reading My own blog Mastering Emacs is full of in depth articles that you should consider reading next A lot of the third party packages like no mode or Emacs s Eshell are described in far greater detail on the website Other Resources There are many community sites and blogs on the Internet Here is a non exhaustive list of some of the ones I recom mend Reddit There is a lively community of Emacs users on the subreddit r emacs It is a small but friendly place and a Conclusion useful source of up to date information on Emacs and new third party packages StackExchange Emacs now has its own site on StackEx change http emacs stackexchange com It is another great place to ask questions Freenode If you prefer live chat the emacs irc channel on Freenode is the go to place for Emacs information As with all rc channels how busy it is waxes and wanes with the time of day but there are many knowledge able people who frequent it Blogs There are many excellent Emacs blogs nowadays I like the following e Sacha Chua http sachachua com blog e Irreal s Emacs blog http irreal org blog e Artur Malabarba http endlessparentheses com e Sebastian Wiesner http www lunaryorn com e Bozhidar Batzov http batsov com e John Kitchin http kitchingroup cheme cmu edu blog Conclusion Howe
80. anything may seem like an unnecessary distraction from your work and indeed a lot of Emacs hacking does happen at the expense of one s real job but once you realize that you can shape your editor to do what you want it to do it opens up a world of possibilities That means you can truly rebind all of Emacs s keys to your liking you are not hidebound by your we s undocumented and buggy ar nor the limitations that would follow if you did change things such as your custom navigation keys not working in say the search amp replace window or in the internal help files Truly in Emacs you can change every thing and people do Vim users are migrating to Emacs because well Emacs is often a better Vim than Vim Emacs pulls you in Once you start using Emacs for the edit ing you realize that using Emacs for Irc email database ac cess command line shells compiling your code or surfing The Way of Emacs the Internet is just as easy as editing text and you get to keep your key bindings theme and all the power of Emacs and elisp to configure or alter the behavior of everything And when everything is seamlessly tied together you avoid the usual context switches of going from application to ap plication most Emacs users use little more than the editor a browser and maybe a dedicated terminal application Emacs s history Emacs s source code repository now in Git stretches back over 30 ye
81. ars and has more than 130 000 commits and nearly 600 committers If you want to modify Emacs or any of the myriad pack ages available to you Emacs Lisp also known informally as elisp is what you will have to write There have been a few attempts to graft other languages onto elisp and Emacs but with no lasting effect As it turns out Lisp is actually a per fect abstraction for a very advanced tool like Emacs And most modern languages wouldn t necessarily stand the test of time Tct was briefly considered in the gos as it was popu lar at the time but that has the distinction of being even more obscure than Lisp nowadays The only downside is that fiddling with your Emacs config uration is something you will have to learn to live with and in Lisp no less but as I explain in the next part that s actually a good thing That s why I reinforced the point that it s a tinkerer s editor If you hate the idea of tweaking anything and want everything out of the box you have two options left The Way of Emacs Use a starter kit There are many free starter kits that come equipped with additional packages and what the author thinks are sensible default settings They can be a good way to start out but with the caveat that you don t know where Emacs ends and the starter kits added functionality begins I recommend you look at one of the following starter kits widely used Steve Purcell s emacs d https
82. as only recently switched on by default So what came before tmm Well for starters you didn t have visual highlighting at all so you had to remember where you left the mark And a lot of the commands didn t know about things like regions at all Simple commands like M x replace string that does a simple string replacement in a buffer worked from the point to the end of the buffer no exceptions So if you wanted to modify particular parts of a buffer you had to use Emacs s cryptic narrowing commands that shrink the visible content of a buffer to what you wanted the command to act on As you can imagine that didn t help beginners learn Emacs So today you don t have to worry about region narrowing for anything except specialized editing nor do you have to memorize the location of the mark as Tm will show you the region However the union of TMM and Emacs s region system is not perfect The mark in Emacs is not just for the region It s an important tool for jumping around in a buffer as some commands that whisk you away from your current location will leave a mark a breadcrumb trail effectively on the mark ring that you can return to later One example would be m lt The Theory of Movement and M gt the commands for jumping to the beginning and end of the buffer they both mark your old position before they jump so you can later return to your old position by typing C u C lt SPC gt The mark ring
83. ated even if you tell Emacs to This is one an noying implementation detail that confuses peo ple Some things like defvar and defcustom forms are only set once So if you evaluate the buffer change a defvar s default value then re evaluate it it won t apply the changes made to defvar The only way to force the change is to press C M x with your point in each defvar or defcustom form If you don t know exactly what I mean by all of this don t worry you can just restart Emacs if you see any of those two forms in your snippet Naturally this is just scratching the surface in using Emacs to evaluate your elisp code You shouldn t need to know much 13http www masteringemacs org article evaluating elisp emacs First Steps more than this to deal with the odd bits of code you see and want to try out Don t be afraid to explore Emacs s capabil ities this way read Emacs s own Introduction to Elisp man ual The Package Manager Since version 24 Emacs has shipped with a package man ager that seamlessly displays and installs packages from cen tralized repositories I credit this change alongside sites like Github with rejuvenating Emacs s 3rd party ecosystem and in turn Emacs itself It s not all roses though there is no one repository you can use for all your needs There s the official enu Emacs pack age repository ELPA but its content is rather sparse as you have to physically sign
84. ater It s common that you will find yourself at a word you want to search for and to save the hassle of typing it in manually you can just type C w Repeated invocations will add subse quent words to the search string I find c m y which adds one character at a time to be of marginal use to most but if you edit a lot of text with foreign characters you will find it useful The Theory of Movement NOTE if you are using an Emacs version older than 24 4 then you must replace c y withm y and m s c e with c y The newer ordering makes a lot more sense as the default yank command is C y outside of Isearch Isearch is an inclusive search and it will generally err on the side of caution and match things that a more traditional stricter search would not You can control how Isearch behaves using its toggles Isearch Key Binding Purpose M s c Toggles Case sensitivity M s r Toggles regular expression mode M s w Toggles word mode M s _ Toggles symbol mode M s lt SPC gt Toggles lax whitespace matching Each toggle command only affects the current Isearch and will not persist The case sensitivity toggle M s c simply turns on strict case sensitive matching useful if you have case folding on by default and you only occasionally need strict case search Toggling regular expression mode with m s r is akin to acti vating regexp Isearch with c m s or C M r and vice versa The word and symbol toggles m s wand m
85. avigational aids work Isearch arrow keys Keys Description RET Visits the file or directory g Goes up one directory q Quits dired n p C n C p Moves the point up down a listing However is the key you need if you want to go up one directory to the parent of your current directory The com mands C n and n amp C p and p go down or up a line but also reorient your point so it is positioned right before the file name When you press RET Emacs will visit the file or directory if it is a directory a new dired buffer is opened So pressing q after visiting a sub directory should take you back to your last dired buffer Marking and Unmarking Marking and unmarking things is something you ll do fre quently if you want to carry out operations on multiple files or directories Keys Description m Marks active The Practicals of Emacs Keys Description u Unmarks active Unmarks everything d Flags for deletion An important distinction must be made between marking and flagging for deletion d flags for deletion and aD is placed next to the flagged item and m marks Marks are never af fected by the delete command and vice versa except for one command that deletes marked files Marked files are high lighted with Marking and flagging both advance the point to the next item as though you d typed c n but you can reverse direc tion with a negative argument Discover more There are so many commands in
86. can change the amount of overlap when you page through text by altering the variable next screen context lines directly in your init file or by using Emacs s customize interface like so M x customize option then enter next screen context lines If you regularly use shells like bash or other cnu readline enabled terminal applications then good news for you by default they use Emacs style keys Try it m f moves forward by word In fact dozens of Emacs s most commonly used commands exist in GNu readline meaning the mental con text switch is minimal and every terminal program that uses read line supports them Moving by Character The arrow key equivalents in Emacs will seem positively strange when you first encounter them A lot of people won der why Emacs would bind an action as common as moving 4The man page on readline has a complete list But why not read the man page in Emacs M x man RET readline RET The Theory of Movement forward a character to c f The fact is if you know Emacs you ll almost never move around by character Moving by character and also by line as that is technically the smallest unit you can move up or down is the small est atomic movement you can make in a buffer Character movement is for finesse made for precision movement if you like Moving around a buffer by character is inefficient and tedious limited by the speed of your keyboard s repeat speed or how fast you ca
87. cludes as you would expect your humble space but also newlines and usually Unicode equivalents like non breaking space Word constituents w This is typically all lower and upper case characters digits and equivalent Unicode characters from non Latin character sets Symbol constituents _ Includes all word constituents and additional symbols like or _ used most often in programming languages This class more than any other is likely to change depending on your major mode Punctuation characters Includes the usual characters like and Text modes and programming modes are likely to differ greatly Open close parenthesis and Any set of characters that form a grouped pair Most text and programming modes include and String characters Includes any symbols that mark a con tiguous block as a string Double and single quotes and are usually among them Unicode characters such as left and right versions guillemots and so on may also exist in this class The Theory of Editing Open close comment characters lt and gt Any character or pair of characters that define the boundary of a comment Some languages only support line level comments in which case only lt is used For instance to match all whitespace characters you should search for s If you want to match all string quote char acters for example in Python where you can have both strings and strings use s t
88. cribe system is one of the best features of Emacs You can find the most important describe keys bound to the c h prefix key there s more a lot more actually but I think most of them are of limited utility to all but elisp writers I use the describe system constantly In writing this book I have used both the info manual and apropos extensively but the describe system is what I use to double check that ev erything I have written is correct If you ever find yourself wondering what a symbol in Emacs does be it a function a command a variable or a mode then describe will tell you The only slight downside to the doc string is that it assumes a technical audience the info manual generally does not It s not all bad you don t have to be an elisp expert to make sense of the description but it will take a bit of time to familiarize yourself with the terminology used in the doc strings Remember the describe system describes a living system your personalized Emacs 16As I mentioned in the Keys chapter you can follow up a prefix key with c h to list all the known bindings First Steps You need to memorize four describe keys as they are the most important ones for day to day Emacs use M x describe mode or C h m Displays the documentation for the major mode and any minor modes also enabled along with any keybindings introduced by said modes The describe command looks at your current buffer This command
89. cus on memorizing C x h as that marks the entire buffer c M h as that will mark the defun and c m lt spc gt as that will mark by s expression and will in most cases act the same if it encounters a word The Theory of Movement I use C M lt SPC gt all the time Combine it with a negative argu ment C M C M lt SPC gt to reverse the direction and you can mark s expressions in reverse easily too Finally a lot of manual marking is redundant if you follow it up with a kill command as Emacs has its own kill commands that act on syntactic units directly I will go into much greater detail about the kill command later on in The Theory of Editing Searching and Indexing Elemental movement commands act mostly on syntactic units Their primary purpose is to serve as successively more precise tools for getting you from A to B from navigating by entire paragraphs or defuns down to moving by a single character Often however you want to search for text Maybe you know exactly what you are looking for and maybe you are not but regardless you need tools to do this effectively Isearch Incremental Search Emacs s incremental search or just Isearch is a supremely powerful search function bound to c s and one you will use a lot in your Emacs career Beneath its simple exterior is a sophisticated set of auxiliary commands 7As you may recall the word kill means cut in Emacs The Theory of Movement Key Bin
90. d you can use F which visits all marked files Importantly it will attempt to open files and give each file its own window which you may not want To avoid this and open them in the background type c u F Keys Description M s a C s Searches all marked files Q Query replace regexp marked files Shell command on marked files amp Async shell command on marked files Occasionally you have to either search through or replace text in files and you can multi file Isearch with the rather awkward key binding m s a c s The command Q does calls c M query replace regexp on every marked file but don t forget to save the changes c x s to query to save every unsaved buffer Call with no marks and dired will attempt to guess the next operation on that file If it s a zip file it will ask if you want to unzip it If it s a patch file Emacs will call patch on it There are many patterns specified in the variable The Practicals of Emacs dired guess shell alist default It is a very useful feature With marks the shell keys and amp call out to a shell com mand They take every marked file as arguments either one per shell command or all of them passed to one command separated by spaces The commands are then run either syn chronously with or asynchronously with amp Consider this scenario we have two files american english and british english and depending on how you phrase the shell comma
91. d you visit a file in Emacs called helloworld py then Emacs will know through a cen tralized register that maps file extensions to major modes that this is a Python file and it should use the Python major mode Each buffer will always have a major mode The major mode may be basic and offer no font locking syntax highlight ing and no specific functionality or it may be the complete opposite and introduce font locking an advanced indenta tion engine and specialized commands Note Font Locking is the correct term for syntax high lighting in Emacs and in turn is made up of faces of properties color font text size and so on that the font locking engines use to pretty print the text You are free to change a buffer s major mode at any time by typing the command for another one In addition to Emacs s register of file extensions and associated major modes there is another system for files with ambiguous or no file exten sions at all Emacs will scan the first portion of the file and try to infer the major mode from that Rarely Emacs will get it wrong and you will need to change it The Way of Emacs It s important to remember that each buffer can have just one major mode Minor modes by contrast are typically optional add ons that you enable for some or all of your buffers One example is flyspell mode a minor mode that spell checks text as you write The major mode is always displayed in the mode
92. defined If you re unsure of what you are looking for maybe you only have part of a name or you just remember a bit of the documentation then apropos is a tool that can help you I find apropos indispensable it s a great way to list all the commands that match certain patterns and an even greater way to discover new commands The Describe System What captures the beauty of Emacs s self documenting na ture is the describe system of commands If you know what you re looking for then describe will explain what it is Ev ery facet of Emacs be it code written in elisp or the core layer written is C is accessible and indexed through the de scribe system From keys to commands character sets cod ing systems fonts faces modes syntax tables and more it s all there neatly categorized The describe system is not static Every time you query a particular part of Emacs it will fetch the required details First Steps through an internal introspection layer which itself queries Emacs s own internal data structures Both the introspec tion layer and internal data structures are queryable by you through elisp There are no secrets in Emacs sure the documented ar layer is the recommended way of accessing Emacs s own internal state but unlike other editors and pes you are not beholden to the package author or Emacs maintainers I think this embodiment of openness beautifully captured by the des
93. ding Purpose C s Begins an incremental search C r Begins a backward incremental search C M s Begins a regexp incremental search C M r Begins a regexp backward incremental search RET Pick the selected match C g Exit Isearch Using Isearch is easy Pick a direction of search You can begin a forward or backward Isearch with c s or c r as per the table above The minibuffer will show I search or I search backward If you previously searched for something you can re call the last search term by repeating the Isearch com mand So if you want to recall the last search term you can type C s C s to first open Isearch and then re call the last search string Emacs will automatically do an incremental search when you do Begin typing Every key you press will trigger the incre mental search engine to find the first match in the direction of your search that matches your search string When it encounters the first match the incremental search engine will highlight all other matches of that search string in your buffer if there are no matches to your search string Emacs will stop when it has matched as much as it can and tell you it has failed The Theory of Movement Browse the matches If you have more than one match or if you simply want to walk through all the matches keep tapping the direction key c s or c r in which you want to search If you want to reverse the direction simply tap the other direction and Emacs wi
94. e Bookmarks You can bookmark see Bookmarks and Regis ters remote files with c x r mand TRAMP will automatically reconnect if you re open a book mark later with c x r b or c x r 1 Bookmarks are extremely useful and a great time saver espe cially for complex multi hops Finally I recommend you add this snippet to your init file It is a custom command that when invoked as M x sudo uses TRAMP to edit the current file as root The Practicals of Emacs defun sudo Use TRAMP to sudo the current buffer interactive when buffer file name find alternate file concat sudo root localhost buffer file name From the above it s easy to tweak the string and build multi hopped commands if you are new to elisp and you need multi hops consider it a fun first place to start learning Conclusion Tramp in conjunction with Emacs s built in shell support and its windows and buffers make it a fine replacement for tmux amp cnu screen based work flows By keeping the remote file editing inside Emacs you unify your environment and you greatly lessen the mental context switching of having disparate Emacs sessions TRAMP is a really powerful feature in Emacs and one that is worth using over other alterna tives it ll never completely replace the incumbent methods of remote editing but it s a good place to start Dired Files and Directories Both browsing and interacting with files and directories on
95. e below but to start with you can get by with these five commands Undoing window changes Sometimes you want to return to a past window configuration The mode m x winner mode remembers your window settings and lets you undo and redo with c c lt left gt and C c lt right gt respectively To enable Winner mode permanently M x customize option RET winner mode RET Emacs will tile windows and generally ensure each new win dow is given roughly half the screen estate of the splitting window If you have just one window and you split to the right you now have two windows each with a 50 share Deleting windows If you use c x then Emacs will delete the active window which is always the one where the point is active and if you type c x 1 Emacs will delete all other windows Splitting windows A window is split either horizontally or vertically or below and right with c x 2 and The Theory of Movement C x 3 respectively If you have a large monitor you may want to split vertically so you can have more than one buffer visible at a time you may even prefer addi tional subdivisions I always split into two or even four windows arranged in a 2x2 grid Finally to move between windows use the command c x o I find it useful to rebind it to M o as it s such a common thing to do Add this to your init file global set key kbd M o other window Directional window selection Some people pre
96. e buffer starting from the beginning of the buffer The Theory of Movement If you want to jump to the 42nd character in a buffer you d type M g c or M 4 M 2 M g c Conclusion As the previous sub chapters have shown there are a multi tude of ways you can move around in Emacs Emacs is often lambasted for being an operating system but a terrible text editor but that could not be farther from the truth Emacs is a highly sophisticated text editor and it easily rivals Vim in capability even if the two editors are functionally dif ferent in their approach Emacs s modifier keys are a form of transient modality Emacs is distinctly modal as your com mands change with the modifier keys and remain so until you release the modifier keys The one thing that will make the biggest difference is remapping Caps Lock to Control I could not live without this even outside of Emacs The control keys are awkwardly placed if you re a touch typist There is also a lot of symmetry to Emacs s commands par ticularly the elemental movement commands Not all key bindings make sense and there are silly oversights like not binding m x imenu to a key If you are new to Emacs I suggest you keep using the arrow keys You can adopt Emacs s movement commands one key at a time Eventually you will slowly adopt certain Emacs isms and you ll soon realize that moving your right hand off the home row to use the arrow keys is slowing you down My
97. e found yourself wanting to collect parts of text as you are re factoring a function perhaps you want to collate several comments into one big group The kill ring lets you do that Killing Lines If you want to kill the whole line you should use C S lt backspace gt but that command won t work in a terminal as it is not possible owing to technical limitations of the terminal emulator The other approach and one favored by me is to modify the behavior of c w the command that kills the active re gion so it kills the current line the point is on if there are no active regions I recommend you install the package whole line or region M x package install RET whole line or region RET Similarly there is C k M x kill line a command that kills from point to the end of the line The behavior is different from The Theory of Editing what most expect c k will not kill the newline character at the end of the line it is advantageous to keep this behavior as the newline character is rarely desired when you want to kill to the end of the line Often c k is like the other syn tactic unit commands used when you want to restructure or rewrite text If the point is at the end of the line the new line symbol is killed so tapping c k twice will kill the text and the newline If you prefer you can force c k to kill the newline also M x customize option RET kill whole line RET Yanking Text In Emacs
98. e kill ring For instance if you type M d M d M d killing three words in a row your kill ring will hold the three words you killed when you next yank the text If you type M d M d M d then move to the next line with c n and kill another three words Your last three words are what you yank from the kill ring not all six The move ment command broke the cycle As I mentioned earlier this is often confusing to begin ners but it s a smart way of working as you don t have to select text first The kill ring can hold many items and like the undo ring you cannot lose information in the kill ring if you kill something and then later on replace your first kill en try with another kill you have not lost your first kill It s easily recoverable and in fact the kill ring is often used as a temporary and secondary store of snippets if you are rewriting text The kill ring is global and between all the buffers in Emacs You can view the kill ring though legible it s meant to be machine readable by running c h v kill ring Killing is also deleting when you don t care about the killed text The kill ring is as much a dumping ground The Theory of Editing for unwanted text as it is a clipboard for useful text There are few outright commands that delete text Emacs will rarely put you in a position where accidental data loss is likely so that s why all bounds commands send text to the kill ring instead
99. e other window It s a surprisingly useful command I almost always work with multiple windows and being able to scroll an other window containing a help buffer or a log file or even another source code file is a common thing for me to do The Theory of Movement Most editors lack this functionality instead you have to Use the mouse With your mouse move over the window and finally use the scroll wheel to scroll up and down or click and press lt prior gt and lt next gt Use the keyboard Switch to the other split window or tab use lt prior gt or lt next gt to scroll up and down In Emacs you can use the other window scroll commands I don t use c M S v often I find it easier to type C M C M v to reverse the direction of the scroll with a negative argument than typing c m s v The latter command requires a partic ularly dexterous finger maneuver and if you scroll too far you have to swap finger positions so you can type C M v It s far easier to use C M and C M v Maintaining tempo Notice that the negative argument command C M is conveniently bound to the same modi fier keys as c M v Like I explained in the chapter on universal arguments this is no coincidence By binding the argument commands to all major modifier combinations you don t have to contort your fingers between commands to prefix a command with an argument You can also scroll horizontally or just left and right in
100. eans if you have particular set tings that apply only to that file you can add them to the header or footer and Emacs will load them au tomatically In practical terms that means everything from indentation settings to more complex variables are controllable from file variables Because Emacs is in effect running code straight from a file all Emacs variables are divided into safe and unsafe The Theory of Movement file variables variables that are declared as safe typ ically by Emacs maintainers are evaluated automat ically For unsafe variables you must first tell Emacs what to do you can ignore the variable or evaluate it once temporarily for that file only or declare it as safe Program loader directives or shebangs are also supported If your file begins with for instance usr bin env python or bin bash then Emacs will figure out the major mode and run it if it is available in Emacs The variable interpreter mode alist lists the program loaders Emacs can detect Magic mode detection uses the magic mode alist variable to see if the beginning of the file matches a pattern stored in the magic mode variable This detection mode is particularly useful if you have no way of annotating the file or predicting the filename or extension ahead of time Automatic mode detection is how most major modes are applied Emacs has a very large registry of patterns that match a file extension file name or all
101. efault directory and picks that directory as the default one for opening new files That is sensible as you may want to open other files that share a directory with the current buffer Typ ing c x c f while editing a file in etc means you may want to open another file in etc so Emacs picks that as your default directory This feature works identically with Tramp and re mote files Invoking c x c f in a remotely edited file and Emacs automatically queries the remote system and not your local one letting you easily open other remote files When you have opened a file rramp does its magic behind the scenes and you ll end up with a file in Emacs that looks and seems much like a local one The only visible way of telling that a file is remote is the modeline a appears be The Practicals of Emacs fore the file name and default directory reflects the TRAMP annotated file path try it inspect the variable with c h v So you can edit files remotely but because of the tight integration between TRAMP and Emacs you can do so much more Invoking commands like m x rgrep works seamlessly with Emacs and tramp The command is run on the remote machine and the results are fed back to Emacs as though you d called the command locally There is no end to the things you can call remotely Here are some of the commands that I use remotely c x d Dired All commands are tunnelled through the re mote session so you can manage your files and d
102. egular Expressions 188 Changing Case 425 246s ete ed eek 194 Counting Things 2 2 0 4 Got pk Siete ecb ey 197 Text Manipulation 6 6404 Sate a Ses 198 Editable Occur oaoa aaa 198 Deleting Duplicates o oo 199 Flushing and Keeping Lines 199 Joining and Splitting Lines 200 Whitespace Commands 203 Keyboard Macros onnaa tw eee al ee 205 Basic Commands 205 Advanced Commands o ooo 207 Text Expansion a e oora ior s ra Tounaa sa 212 Abbrev oaoa aa 214 DAbbrev and Hippie Expand 215 Indenting Text andCode 218 RET Indenting New lines 219 TAB Indenting the Current Line 219 Indenting Regions 221 Sorting and Aligning 3 2 oaea 8 A Re eS 222 SOTING ne hed Sa oaa a E a e ota 223 Aligning oaaae aaa 226 Other Editing Commands 232 Zapping Characters 5 4 4 84 da eS 232 Spell Checking Scctey how es ag es 233 Quoted Insert niesos Ms Ae ded Se 235 The Practicals of Emacs 236 Exploring Emacs ossaa je eRe aE 237 Reading the Manual 237 Using Apropos 2 53 2udiwee oe eet 238 c h Exploring Prefix keys 241 c h k Describe what a key does 242 C h m Finding mode commands 243 Working with Log Files 2 244 Browsing Other Files 247 TRAMP Remote File Editing 247 Multi Hops and User Switching 252
103. ell them apart It is especially useful if you want to find trail ing whitespace errant tab characters or empty lines with whitespace in them Whitespace mode tracks the following trailing spaces tabs spaces lines that are longer than whitespace line column typ ically 80 characters newline characters empty lines inden tation both tabs and spaces spaces after tabs and spaces be fore tabs Basically it tracks every conceivable combination that may cause syntax or typography errors I suggest you customize whitespace mode particularly the colors as they are a bit full on by customizing the group whitespace with m x customize group You can also use M x whitespace toggle options and toggle the styles you want whitespace mode to highlight Whitespace Reporting and Cleanup Command Description M x whitespace report Shows whitespace issues M x whitespace report region As above but for the region M x whitespace clean up Attempts automatic cleanup M x whitespace clean up region As above but for the region The Theory of Editing You can generate a report with m x whitespace report and similarly for regions and see a succinct list of issues present in your buffer or region Furthermore you can ask Emacs to attempt a cleanup of the buffer or region with the equivalent cleanup commands Keyboard Macros You can record keystrokes and commands in Emacs and save them for later playback as a keyboard
104. ello and not Hello or HELLO If you searched for Hello or HELLO Emacs would only replace those literal matches because they contain uppercase charac ters The Theory of Editing Regular Expressions Earlier I alluded to the differences between pcre and Emacs The long and the short of it is Emacs s regexp engine is nowhere near as user friendly as it could be It s old weathered and too entrenched and heavily modified to suit Emacs s peculiar needs to be easily replaced For instance in pcRE style engines the characters and are meta characters meaning the engine will not treat them as literal characters but as a capturing group In Emacs it is the other way around They are literal characters until you escape them with a backslash at which point they assume the role as meta characters In practical terms that causes confusion in regexp building for people unaccustomed to Emacs s quirky regexp engine It s even worse if you write elisp as you have to escape the escape character as Emacs s C style string reader would oth erwise trigger on backslashes I will not cover regular expressions in great detail since that is a whole book onto itself Instead I will tell you how Emacs s regexp engine differs from modern ones Backslashed Constructs The following constructs require backslashes or Emacs will treat them like literal characters Constructs Description Alternative G Capturing group
105. ely Discovering the Kill Commands Use Emacs s apropos functionality to find addi tional kill commands not listed here Emacs s kill commands use the same syntactic unit concept as the movement commands do Some of them also share mod ifier symmetry making it easy to switch between kill com mands The Theory of Editing Key Binding Purpose Ged Delete character lt backspace gt Delete previous character M d C lt backspace gt Kill word C k Kill rest of line M k Kill sentence C M k Kill s expression C S lt backspace gt Kill current line The ones that stand out in the table above are c d which deletes the next character and lt backspace gt which does the same but backwards All other commands kill and don t delete The distinction is important deleted text is not retained in your kill ring whereas killed text is Digit Arguments and Negative Arguments Like the movement commands you can use the digit ar guments to kill more than one unit at a time To maintain your tempo ensure you use the same digit modifier as the modifier of the kill command you want to call If you want to kill 3 s expressions with C M k type C M 3 C M k The negative argument reverses direction just like the movement commands Make no mistake that is more useful than it seems I frequently finish writing some thing only to realize I want to move it elsewhere or perhaps delete it entirely Consider this example s m
106. ents or What characters make up a word and although obscured from view affects every part of Emacs The syntax table alone decides the makeup of a word or symbol punctuation comment etc as a syntactic unit So when you move the point around on the screen it moves The Theory of Movement according to the syntax table and the general rules governing forward word and backward word The syntax table Every editor has an equivalent of Emacs s syntax table but what sets Emacs apart from other edi tors is that you can inspect and change the syntax table which in turn will affect how your point moves across the screen when you invoke certain commands You can view your current buffer s syntax table by typing c h s it may take a while to load In it you will see a human readable version of the characters and their assigned syntax class Movement Asymmetry One more thing you should know about word movement is that it s not symmetric typing m f followed by m b in theory it should take you back to your old position is not guaranteed Emacs will cleverly skip symbols and punctuation it encounters in the direction forward or backward you re moving Consider what happens when you type m f to move forward one word Before Hello JWorld After Hello Worldff The Theory of Movement Because the characters succeeding the point J are all alpha betical characters the word command behaves as you would
107. eresting things you can do when you choreograph Emacs s movement and editing Chapter 2 The Way of Emacs The purpose of a windowing system is to put some amusing fluff around your one almighty emacs window Mark gnu emacs help If you imagine the span of the modern computing era be ginning in the 1960s then Emacs has been there longer than just about everything else It was first written by Richard Stallman as a set of macros on top of another editor called TECO back in 1976 TECO is now mostly remembered for be ing even more obtuse and hard to understand than Emacs and pos era WordPerfect combined Since then there have been many competing implementations of Emacs but today you re only likely to encounter XEmacs and cenu Emacs thttps www gnu org software emacs manual html_mono efaq html Origin of the term Emacs 13 The Way of Emacs This book will only concern itself with enu Emacs Once upon a time XEmacs was the more advanced and feature rich editor but this is no longer the case from Emacs 22 on wards cenu Emacs is the best Emacs out there The history of XEmacs and Gnu Emacs is an interesting one It was one of the first major forks in a free software project and both XEmacs and cenu Emacs are developed in parallel to this day Note To almost everyone the word Emacs refers specif ically to enu Emacs I will only spell out the full name when I am distinguishing between differ ent
108. es The Theory of Movement and its filter as you type is clearly superior to Emacs s own TAB based completion mechanism for many but not all tasks How to install Helm is a third party package and does not ship with Emacs To download it 1 Ensure you have followed the instructions in The Package Manager 2 Run M x package install then enter helm and press RET 3 Add this line to your init file require helm config All Helm commands share the prefix key c x c I can t say I am a big fan of that prefix key as a lot of the keys that follow it make it an exercise in finger contortion It is also remark ably close to c x c c the command that exits Emacs Prefix Key Binding Purpose C x c Prefix key for all Helm completion commands Helm s Deep Helm is a deep and complex tool that rewards you if you spend the time discovering what it can do The trick to discovering things in Emacs is to ask Emacs the The Theory of Movement right questions The right questions in this case are What commands does Helm make available to me and Does Helm have any key bindings Use apropos As I talked about in Apropos apropos will list all elisp symbols variables commands elisp functions and so on that match the pattern you give it In this case asking M x apropos command using C h a to show you all commands that match helm would be a good place to start Likewise M x apropos variable
109. etions found by DAbbrev there is no equivalent completion list for Hippie Expand Actively using m takes a bit of practice You ll have to de velop an affinity for the sort of expansion rules that apply when you call it Learning Hippie Expand is so worth it since it is a great time saver Customizing Hippie Expand You can alter how Hippie Expand expands text To do this customize the variable hippie expand try functions list but you have to know the name of the try function if you want to add a new one To find a list of try functions you should e Read the commentary in the source M x find library then enter hippie exp and read the documentation The Theory of Editing e Use Apropos Look at the names of the try functions and search for likely functions using M x apropos function As always both methods yield different answers so try both Indenting Text and Code When new programming languages appear a major mode for Emacs that does basic syntax highlighting and indenta tion appears almost immediately Part of what makes that possible is the ability to not only inherit or re use indenta tion engines from other major modes but also the generic indentation engines present in Emacs Older versions of Emacs for some inexplicable reason wouldn t indent by default when you pressed Ret That correctly infuriated a lot of beginners But in Emacs 24 4 a new minor mode called electric indent mode now hand
110. eveals a handful of interesting com mands Keys and Commands Description C x v Prefix key for vc M x vc dir C x v d Shows ve status for current dir M x vc diff C x v Displays diffs between file revs M x vc annotate C x v g Blames annotates current file M x vc next action C x v v Does next logical action M x vc print log C x v 1 Prints commit log The Practicals of Emacs With these it s easy to see a trend A lot of the commands are bound to the prefix key c x v The next step would be to see what commands are bound to the prefix key itself by appending C h c h Exploring Prefix keys In Discovering and Remembering Keys I showed you that appending c h when you enter a partial prefix key lists all the keys bound to that prefix key c x v is no exception typ ing C x v C h lists all the keys bound to this prefix key Typing c x v c h yields this Global Bindings Starting With C x v key binding vc update vc diff vc root diff ll vc ignore vc log incoming vc print root log vc log outgoing vc update change log Tuor Hw aga vc switch backend TmM7 ADNADADAANAAAAA DN 1 x xX KX KX KX KX KX K KM lt lt lt lt lt lt lt lt lt The great thing about this command is that it is so easy to type If you forget that c x v diffs the current file with the last file revision No problem c x v c h shows that bound to c x v isM x vc diff The other obvious benefit The Prac
111. ew buffer Emacs won t hassle you for a filename The buffer will exist in Emacs and only Emacs You have to explicitly save it to a file on disk to make it persist Emacs uses these buffers for more than just editing text It can also act like an 1 o device and talk to another process such as a shell like bash or even Python Almost all of Emacs s own commands act on buffers So when you tell Emacs to for example search amp replace it The Way of Emacs will actually search and replace on a buffer maybe the active buffer you re writing in or perhaps a temporary duplicate and not an internal data structure like you might think In Emacs the buffer is the data structure This is an extremely powerful concept because the very same commands you use to move around and edit in Emacs are almost always the same ones you use behind the scenes in elisp So once you memorize Emacs s own user commands you can use them in a simple function call to mimic what you d do by hand The Window and the Frame When you look at a buffer on the screen it is displayed in a window But in Emacs a window is just a tiled portion of the frame which is what most window managers call a win dow In Emacs it is the other way around and yes it s very confusing If you look at the screenshot above you will see two win dows and one frame Each frame can have one or more win dows and each window can have exactly one buffer So a buffer
112. f this book The first and most obvious audience are people new to Emacs If you ve never used Emacs before in your life you will hopefully find this book very useful However if you re new to Emacs and non technical then you re going to have a harder time Emacs despite being suitable for much more than just programming is squarely aimed at computer savvy people Although it s perfectly possible to use Emacs anyway this book will assume that you re technically inclined but not necessarily a programmer If you ve tried Emacs before but given up then I hope this book is what convinces you to stick with it But it s fine if you don t some languages or environments don t contrary to what a lot of Emacs users would claim work well with Emacs If you re primarily a Microsoft Windows developer working with Visual Studio using Emacs is going to be a case of two steps forward one step back you gain unprece dented text editing and tool integration but lose all the ben efits a unified mE would give you If you re a Vim refugee then welcome to the dark side If your primary objective is to use Emacs s Vim emulation lay Introduction ers then some of this book is redundant it concerns itself with the default Emacs bindings and it teaches the Emacs way of doing things But not to worry a lot of the tips and advice herein are still applicable and who knows maybe you ll switch away from Evil mode in
113. fer the windmove package that ships with Emacs as it lets you move in cardi nal directions instead of cycling through all win dows You can enable it by adding this to your init file windmove default keybindings You can now switch windows with your shift key by pressing s lt left gt S lt right gt S lt up gt S lt down gt Working with Other Windows Once you re comfortable splitting and deleting windows you can build on that by acting on other windows That is if you want to switch another window s buffer you The Theory of Movement have to C x o to the window then use c x b to change the buffer It s a bit tedious and it breaks your tempo The other window in this case is the one immediately after the current one when you run C x o Key Binding Purpose C x 4 C f Finds a file in the other window C x 4d Opens M x dired in the other window C x 4 C o Displays a buffer in the other window C x 4 b Switches the buffer in the other window and makes it the active window C x 4 Kills the buffer and window These commands are the most useful ones for operating on other windows There are a few more you can use C x 4 C h to list them but you won t use them as often If you look closely at the key bindings in the table above you will see a symmetry between c x 4 and c x indeed they are almost identical in binding and purpose This is no coincidence and the symmetry will help you remember the
114. finition or comment point is visible in the buffer In other words it will try and scroll things into view I use C 1 all the time I use it to recenter the line I m on so I can see more of the buffer above or below the line I am on I encourage you to try out M r and c 1 The goal column command c x c n is of limited interest to most people When you move up or down a line Emacs will try to maintain your horizontal position as you move from one line to the next If you have a goal column set Emacs will not do that and instead make your point s horizontal po sition match the goal column So if you set the goal column to 10 C 1 C C x C n Emacs will try if the line is long enough to ensure your point is always placed at the tenth character To disable goal column type C u C x C n Jumping to a line is frequent enough but because of things like Emacs s interactive compilation mode and built in support for things like grep you don t have to jump to explicit lines as often as you d have to if you used a simpler editor The command bound to m g m g works exactly as you would expect it asks you for a line to which to jump You can also give it a prefix argument for instance M 5 M 5 M g M g to jump to the 55th line and make sure you use the m digit argument to maintain your tempo The command m g TAB does the same only it jumps to a partic ular column position instead M g c jumps to the absolute po sition in th
115. for historical reasons Super and Hyper but don t have dedicated keys on today s keyboards but for consistency with Space Cadet keyboards still exist inter nally another key Alt does exist on modern keyboards but is bound and known by as Meta in Emacs Modifier Full Name s Super not shift H Hyper A Alt redundant and not used Super and Hyper can still be used and if you re the owner of a Microsoft Windows compatible pc keyboard with the Start and Application Context buttons you can rebind them to serve as Super and Hyper which is very useful Emacs supports the modifiers natively but you need to tell your operating system or window manager to bind them Important ghttp home comcast net mmem kbd SpaceCadet html First Steps Owing to the limitations of terminals there are some key bindings you simply cannot type if you re running Emacs in a terminal My advice is to run Emacs in a cut if at all possible Knowing the modifiers is only one half of the equation though In Emacs we formally define a key sequence or just key to mean a sequence of keyboard or mouse actions and a com plete key to mean one or more keyboard sequences that invoke acommand if the sequence of keys is not a complete key then you have a prefix key And if the key sequence is not recog nized by Emacs at all it is invalid and an error is displayed in the echo area That s a rather dry definition so let s l
116. for lines that match the regular expression and shows you the results in a separate buffer Occasionally you may want context lines lines before and after the matching line itself and you can enable them by customizing the variable list matching lines default context lines Occur mode uses hyperlinks that jump to the matching line when you left click it with the mouse or press RET on your keyboard The occur mode used in the occur buffer has a number of useful keys you can use Occur Key Binding Purpose M n M p Go to next and previous occurrence lt gt Go to beginning and end of buffer g Revert the buffer refreshing the search results The Theory of Movement Occur Key Binding Purpose q Quits occur mode e Switches to occur edit mode C c C c Exits occur edit mode and applies changes The keys are only available in the occur buffer itself In Emacs the key g will revert the buffer What happens when you do that depends on the mode but it s a common Emacs convention to refresh the contents from the original source In this case it will re run the search on the buffer with the same regular expression The g command is worth remembering as it s such a common convention in Emacs The e key will switch the occur buffer to an editable state This is an unbelievably powerful editing construct that lets you edit the text in line in the occur buffer and then commit the changes to the original source lines by typin
117. ft gt S lt right gt etc will region select one character at a time and c s f will do the same but with Emacs s own movement commands To disable or enable it use the customize interface M x customize option RET shift select mode M x cua mode Probably the most radical departure from Emacs s selection and clipboard system is cua mode Named after 13m s Common User Access cua mode lets you use C z C x C c and C v to undo cut copy and paste like you would in other programs Because cua mode and Emacs s own prefix key bind ings C x and c c conflict cua mode is disabled by de fault If you enable it the prefix keys c x and c c con tinue to work but with minor side effects and addi tional constraints The Theory of Movement 1 To type the prefixes c x or c c with an active re gion you must double tap the prefix key in rapid succession e g C x C x 2 To type the prefix key c x or c c followed by an other key you must type them in rapid succes sion or you will trigger a clipboard command 3 Alternatively to points 1 and 2 you can type the prefix key with the s modifier c s x replacing c x and c S c replacing c c cua mode is one of those quality of life features that will make or break Emacs adoption for some people If you re one of them by all means enable it You can always wean yourself off the cua keys over time or sim ply live with the side effects I mentioned To enable or disable
118. g Emacs Eventually you ll commit to muscle memory the commands and keys you use most frequently and the rest well you can always look them up Use Emacs long enough and those of you who have reached this point already will probably agree with me and one day it just clicks And when it does it s not because you have managed to memorize a thousand key bindings It s because Emacs is no longer an opaque box but a very open and transparent one that you can peer into modify and observe the results of those changes The reading order of this book is presented in the same way that I would teach someone Emacs if they sat next to me Un derstanding the terminology is important as it lays a founda Conclusion tion next is the most basic of keys and commands so you can use Emacs and then comes the movement and editing commands followed by some practical examples to help re inforce what you have learned and to give you some ideas on where to go from there Finally I want to touch on what you should do once you feel you have nothing more to learn from this book The natural next step is learn elisp it s a fun language even if the tsp di alect lacks a lot of the bells and whistles of more modern tisps Learn tsp and you ll appreciate why curmudgeonly old timers decry modern programming languages as infe rior versions of Lisp and they re half right too Once you see LIsp s data as code concept in action
119. g c c c c The main advantage of the occur mode is that you get a second buffer with the results usually in a second window next to your original buffer and an at a glance view of the matches and the ability to jump between the matching lines However that requires that you keep switching to the other window to select new matches that is not only tedious but it ruins your tempo To maintain your tempo I suggest you learn these two commands Key Binding Purpose M g M n Jump to next error M g M p Jump to previous error The Theory of Movement The purpose column says error but that s because the com mand names are M x next error and M x previous error In reality they are general purpose commands When you run M x occur or other specialized commands in Emacs like m x compile or M x grep Emacs remembers that and makes m g M n and M g M p go up and down that list of matches The great thing about these commands is you only have to re member those two and they will work with the last known occur compile or grep search you did Multi Occur You can use the occur mode on multiple buffers with multi occur The command m x multi occur in matching buffers takes a regular expression of buffers to match for instance py to search all Python buffers but other wise works the same as M x occur There is also M x multi occur where you explicitly select the buffers you want to search also useful but
120. gative argument Note The negative argument commands are bound to the minus key even though it s hard to make out from the table above They re written as C instead of c because the latter is an invalid Emacs key you cannot press a modifier key c release it and then press That would just print on your screen It s the minus itself that is bound to several modifiers White space matters So I mentioned the importance of tempo Once you re com fortable with Emacs you ll be flying across the screen and not having to take your fingers off the modifiers to apply a negative or digit argument will help you do that Ensuring the digits and negative arguments are bound to the modifiers c M and c m three very common modifier combinations all but guarantees you won t have to move your fingers from the modifiers before you follow them up with your intended command Here are a few examples of what I mean First Steps m M d kills the previous word before point Without M M d would kill the word immediately following point The command has synergy with the negative argument because you can keep your finger on the meta key and press d This combination maintains your tempo c M d does exactly the same but it will take you about thrice as long to type You have to press c release the control key and then press m followed by d This combination breaks your tempo A lot of people never bo
121. geRed 1 Customize Apropos All of 387 3 0 Cust The Customize interface is rather byzantine but once you understand how it works it s quite easy to use The figure above shows one face font lock string face That s the actual elisp variable name for the face the pretty printed name is Font Lock String Face and what you ll see in the figure above To the immediate left is an arrow it s tiny but it ll hide show each face On a Terminal it s replaced with the arguably more legible texts Hide or Show As a quick aside the Customize interface is made up of two things faces and options Options are a catch all term for things you can Customize that aren t faces The font lock string face governs the face for strings and what a string is depends on the mode in which it is used For most programming major modes it ll be for actual literal strings in the source code but mode authors are free First Steps to use the font faces for whatever they please Having said that most adhere to the naming standard for each face Customize Apropos home Operate on all settings in this buffer Apply Apply and Save vy Font Lock String Face state Font Lock mode face used to highlight strings Font Family Font Foundry Width Height Weight Slant Underline Overline Strike through Box around text Inverse video Foreground OrangeRed Distant Foreground
122. ged DAbbrev replacement that expands more than just words but whole lines lisp symbols Abbrev abbreviations file names and file paths and other useful things This feature is excep tionally powerful and it s a drop in replacement for Emacs s default DAbbrev that also ships with Emacs Skeletons A complex templating tool that combines sim ple elisp primitives prompts region wrapping inden tation and point positioning with Abbrev like expan sion Although it has been a core part of Emacs for more than 20 years few use it It s a shame really as it s very powerful but it requires patience or elisp knowledge to use almost so no one does Tempo Yet another templating tool that ships with Emacs It is similar to Skeletons YASnippet A third party package templating tool inspired by the text editor TextMate s template tool and TextMate itself borrowing heavily from other tools before it It uses a simple template language to create snippets that you can trigger with tab or space and expand into editable templates It s similar to Skeletons but arguably much easier to use The Theory of Editing Autoinsert Inserts templates much like skeletons when you create a new file that matches a certain file type It is useful when you want to auto generate boilerplate content in a file such as HTML tags like html head and so on Of all the choices above I would focus my attention on YAs nippet
123. h Isearch Key Binding Purpose C M Query regexp search and replace M Query search and replace The query commands are interactive and will prompt you for instruction at every match Like Isearch the interface is rather spartan but utilitarian It is also divided into two parts the prompts for search and replace which work the same way other prompts do and the interactive part where you select each match When presented with a match you can choose one of the following options Query Key Binding Purpose SPC y Replaces one match then continues Replaces one match then exits RET q Exits without replacing match Replaces all matches in buffer i Moves point back to previous match The Theory of Editing Case Folding In Isearch Incremental Search I talked about case folding a clever feature in Emacs that intelligently matches string case insensitively unless you search for a mixed case or uppercase string at which point it activates case sensitive search It s a great feature and Emacs s replace mechanism also uses it Consider a buffer with the following pseudo code HELLO WORLD Hello World function hello print HELLO_WORLD If we do a query replace with c m for hello gt goodbye the result of the buffer above is GOODBYE_WORLD Goodbye World function goodbye print GOODBYE_WORLD As you can see Emacs preserved the case of each replacement match because we searched for h
124. hen you type C x b The Theory of Movement Key Binding Purpose c sandc r Move to the next and previous match TAB Traditional non 1po TAB completion RET Switch active buffer to selected match Further reading I recommend you read my article Introduction to Ido Mode on my website for further in depth information on how to use po mode Grep Searching the file system Searching files already open in Emacs is useful but more often than not you want to search files that aren t open in Emacs and the command line utility grep is a great way to do just that grep in Microsoft Windows There is no like for like grep program in Win dows and the built in one findstr though powerful is not supported out of the box by Emacs so I recommend you install the cross compiled Windows versions of the cnu Coreutils They work splendidly in Windows and they give you a reasonable Linux command line facsimile in Windows tohttp www masteringemacs org article introduction to ido mode tihttp gnuwin32 sourceforge net packages coreutils htm The Theory of Movement How you interact with grep or more generally with any ex ternal tool depends on your editor Many Vim users would exit Vim or use a tool like tmux or screen and switch to a terminal and run the command s and then return to Vim Emacs users prefer tools they can assimilate into Emacs Us ing grep from inside Em
125. her commands and it detects when you try to access remote files using a spe cial syntax not unlike what command line tools such as scp use What makes Tramp great is its total transparency If you didn t know Emacs had remote editing capabilities you d never know It is quick and seamless to reach out and edit remote files All rramp connections follow this syntax protocol user hostname port TRAMP supports many protocols both old and new but nowadays the one you are most likely to use is ssh or maybe scp For a full list of TRAMP protocols and how they work consult the variable tramp methods or the info manual page tramp Internal methods Microsoft Windows On Windows your protocol choices differ If you dont use Cygwin or a cross compiled version of OpenSSH you will need to install PuTTY s plink exe tool and use plink as the protocol Although the server landscape is a lot more homogeneous today than it was 15 years ago TRAMP does a lot of behind the scenes work to ensure the remote shell delivers a consis tent and dependable experience The variable I mentioned The Practicals of Emacs above tramp methods controls how Tramp handles each pro tocol type If you work with obscure systems you may have to customize this variable Another nifty feature of Tramp is that it parses your ssh config file and suggests them when you have entered ssh as your protocol You can of course specify bo
126. hink that level of detail is unnecessary As a writer I have written and then rewritten some text and my undo ring now looks like the one below The ring is to be read top to bottom with each undo record separated by the arrow going from newest to oldest When the END marker is reached the undo ring is empty and no more undo actions are possible gt vr is the Roman numeral for 6 vr vi vr is the number of the beast END This undo ring has two undo records in it each one a line of text The head of the ring is the triangle gt indicating the The Theory of Movement latest undo record If I undo once with c my undo ring now looks like this v1 is the Roman numeral for 6 gt vr vI vI is the number of the beast END The original quote is still in the undo ring in fact it hasn t really gone anywhere at all though the text in the buffer has changed to what gt points at Instead we ve shifted the head the triangle to the other quote If I did another undo step I would end up at END and now my buffer is empty I m not going to do that though as I will instead write another quote vi is a text editor And now my undo ring looks like this gt v1 is a text editor gt vr is the Roman numeral for 6 vr vi VI is the number of the beast END The head of the undo ring has changed to point at the latest quote I just entered but the old qu
127. ific area or problem in some depth Unlike the last two chapters I won t cover the commands and features I introduce in this chapter in any great detail I leave that to you to discover on your own time If you are 236 The Practicals of Emacs still unsure how to do discover new features then read on the first part of this chapter is Exploring Emacs Exploring Emacs To truly master Emacs you have to learn how to find things It is alpha and omega in Emacs Manuals books and blog posts make assumptions about your editing environment about Emacs Once you change variables rebind keys or al ter Emacs to suit your own needs you create a unique combi nation of changes that few other people if any have There fore to diagnose issues or fix and change things you dislike you have to know how to find those things in the first place Let s explore vc Emacs s Version Control interface The vc system is a powerful and underutilized facility in Emacs that exposes a generic interface for things like version history blaming committing pushing and pulling that then talks to your chosen version control system vc is especially use ful if you work regularly with more than one versioning system If you weren t aware of vc before and your first introduction to it is reading about it now how would you learn about it Reading the Manual Unsurprisingly Emacs s manual is well written and exten sive Looking
128. ile called emacs but most keep their customizations in emacs d init el on Linux and HOME init el on Windows Since Emacs now writes several more files to your file system they are kept in a directory called emacs d to avoid cluttering your home directory So when people talk about their init file or their emacs file or if they tell you to put something in said file that s what they re referring to If you are new to Emacs you should use emacs d init el When you add something to the file you will need to tell Emacs to run it There are many ways of doing this and I will explain how in Evaluating Elisp Code but my preferred recommendation for beginners is to close Emacs and restart it Note Starter kits in Emacs are very common now Theyre community additions to Emacs that bundle many changes and even entire third party packages and if you use one you should read their documentation for best practices on where to store your own changes Emacs will not save changes for you If you want Emacs to keep changes you must do it through the Customize inter face That means it is your responsibility to save changes you The Way of Emacs want to keep to init el Likewise if you made a mistake and broke something in Emacs or if you made changes you do not care for simply quit and restart Emacs Major Modes and Minor Modes Major modes in Emacs control how buffers behave So if you want to edit Python code an
129. ill split the current line and insert the fill prefix on the new line Contrarily m removes fill prefixes from lines that you join The Theory of Editing Whitespace Commands Managing whitespace is an issue that recurs often when you yank text from elsewhere or if you work with languages where whitespace is significant Command Description M SPC Deletes all but 1 space or tab to the left and right of the point M x cycle spacing As above but cycles through all but one all and undo M Deletes all spaces and tabs around the point M sPC is useful as it trims all whitespace to the left or right of the point to a single whitespace character M does the same but removes all whitespace characters leaving none M x cycle spacing cycles between leaving one leaving none and restoring the original spacing You can tell Emacs to visibly show you whitespace charac ters and other typographic snafus like trailing spaces or overly long lines using Emacs s whitespace mode Whitespace Minor Mode Command Description M x whitespace mode Minor mode that highlights all whitespace characters M x whitespace newline mode Minor mode that displays newline characters with a The Theory of Editing Command Description M x whitespace toggle options Displays a toggle menu of all whitespace mode options Emacs s whitespace minor mode overlays otherwise invisi ble whitespace characters with glyphs and colors so you can t
130. implementations When I mention Emacs I always talk about enu Emacs Because of Emacs s age there are a number of oddities Weird choices of terminology and historical anachronisms persist because in most cases Emacs was ahead of the editor IDE curve for many decades and thus had to invent its own terminology for things There are talks of replacing Emacs s own vernacular with words familiar to everyone but that is still a long way off Despite the lack of marketing a small core of Emacs devel opers the anachronisms and terminology that predates the modern Personal Computing era there are many people out there who just love using Emacs When Sublime Text showed off its mini map feature a miniature display of the source code someone immediately coded up a minimap package doing the same thing in Emacs In fact it is this 2http www jwz org doc lemacs html The Way of Emacs extensibility that attracts some to and repels others from Emacs This chapter will talk about the Way of Emacs the terminol ogy and what Emacs means to a lot of people and why un derstanding where Emacs comes from will make it easier to adopt it Guiding Philosophy Emacs is a tinkerer s editor Plain and simple People who hack on Emacs do it because almost every facet of it is extensible It is the original extensible customizable self documenting editor If you come from other text editors the idea of being able to change
131. indings Because of the sheer number of Helm commands I will list the ones I think are the most important I encourage you to follow the suggestions in Helm s Deep and explore Emacs and Helm yourself Before I do that I should talk about Helm actions In Helm you can also carry out actions against the matches the ac tions available depend entirely on the completion you are doing Helm has its own set of keys that you need to learn Helm Key Binding Purpose RET Primary action C e Secondary action C j Tertiary action The Theory of Movement Helm Key Binding Purpose TAB Switch to action selector C n C p Next and previous candidate M lt M gt Beginning and end of completion list RET is the primary and most common action you d want to carry out on the selected candidate Usually it will jump to open or display the candidate The secondary action if there is one is bound to c e which you may remember is an ele mental movement command that jumps to end of the line the command will still do that in Helm but only if your point is not at the end of the line if it is it acts as the secondary action Exiting Helm To quickly exit Helm press c g the universal get out of anything key The taB key will switch to the action selector and list all available actions for the selected candidate Like the Helm completion interface the action interface is also filter as you type Here are some of the
132. ing it is usually a lot of fun to do this but I think in the long run it s worth doing I still use the Customize interface myself when I change font faces There are hundreds of font faces First Steps in Emacs everything from font lock faces syntax highlighting to the color of the modeline the fonts to use for the info manual and more The Customize Interface The Customize interface is divided into groups and sub groups Each group typically represents one package mode or piece of functionality The top level group is called Emacs and con tains as you would expect all other groups To access the customize interface type M x customize A buffer called customize Group Emacs should appear with a list of groups This is one part of Emacs where using a mouse can be beneficial the interface has buttons hyper links and edit boxes much like a browser would Click around explore the interface and marvel at just how much stuff there is to configure And that s just the things exposed to the Customize interface hint If you re using Emacs 24 1 or later you can use the Search bar at the top of the Customize interface to search for things by name First Steps Customize Apropos home For help using this buffer see E s the Operate on all settings in this buffer Apply Apply and Save vy Font Lock String Face State Font Lock mode face used to highlight strings u Foreground Oran
133. ing these concepts to other file types For instance Emacs ships with auto compression mode a passive mode enabled by de fault that automatically de compresses and re compresses files when you open and save them Combine it with m x dired and you can browse compressed archives as though they were directories A very nifty feature indeed and it s seamless You can also open images and even pprs in Emacs if image support is compiled into your build of Emacs and like auto compression mode this mode also works transparently in the background You can even combine image viewing with M x auto revert mode and automatically revert images if they change a huge time saver if you re generating images TRAMP Remote File Editing Remote file editing is usually awkward you have to interact with a remote environment usually using a terminal emula tor and almost always without the fidelity of a graphical interface and your usual settings Even though it s trivial to move your emacs d around with you it is still awkward For all the improvements in technology remote file editing usu ally involves trade offs Emacs s TRAMP system is a transparent proxy that aims to solve most of the remote file interaction woes you are likely 1 Transparent Remote file Access Multiple Protocol The Practicals of Emacs to encounter TRAMP is without a doubt the coolest feature in Emacs TRAMP works by monitoring c x c f and ot
134. ion M x count words Counts words lines and chars in the buffer M x count words region M Counts words lines and chars in the region Although there is more than one way of counting things the The Theory of Editing two worth memorizing are M x count words as it unlike its unfortunate name implies also counts lines and characters You may occasionally want to count things in a region in which case you can use M M x count matches is also useful as it counts matches against a regexp pattern you specify Text Manipulation Text manipulation is one aspect Emacs is especially good at and it has a variety of tools to help you Massaging text files for further processing or extracting pertinent information from log files are both common things to do in Emacs Al though Emacs will never fully replace dedicated tools like awk and sed or languages like Python it is a fine choice for small and medium sized tasks Editable Occur I introduced m x occur in Occur Print lines matching an expression as a way of collating all lines that match a certain pattern One feature in occur mode that I did not talk about is the ability to edit the matches and after you finish commit the changes to their original lines To do this you must first enter the editable occur mode by typing e You can then commit the changes you make by typing c c c c The possibilities are limitless The feature is especially great for keyboard macros
135. irec tories with dired as though they were local You can even copy files between remote and local dired sessions and Tramp will transparently copy the files across M x compile Compile You can enter a compile command such as make or python manage py runserver or indeed anything you like Emacs runs the command remotely and the output is shown in the compilation buffer You can even run interactive servers remotely with live feedback M x rgrep Grep Commands Both find and grep are called remotely and as with the other commands the results are displayed in Emacs Hyperlinked files in the grep output correctly open the remote file M x shell Emacs s Shell Wrapper Starts a remote login shell and hands you control of it It works just like m x The Practicals of Emacs shell on a local machine but the shell in this case is obviously on the remote machine TaB completion which in m x shell is done by Emacs and not the actual shell also works M x eshell EShell Emacs s elisp shell Eshell is a shell written in Emacs lisp It also transparently works with remote TRAMP connections In fact you can cd into remote directories straight from a local shell Multi Hops and User Switching Another useful ability of Tramp is account elevation with su or sudo This is extremely useful even for local files if you want to edit a file as another user or root The ability to do this also neatly ties in with the concept of
136. it calls the aforementioned function in indent line function The default function is indent relative a command that inserts an actual tab char acter Modes such as text mode and fundamental mode the default mode for a new empty buffer uses indent relative Most programming modes do not The Theory of Editing Changing the amount of indentation The variable tab width controls how many char acters of spacing each tab uses It also controls the amount of whitespace to use if you disabled indent tabs mode There is also the concept of tab stops in Emacs and you can edit the tab stops by typing M x edit tab stops and inserting characters where you want Emacs to set the tab point Subsequent calls to m i which calls the command M x tabs to tab stop then insert tab stops by way of whitespace and tab characters Indenting Regions Regions are even more difficult to indent How do you safely indent a region Python code when block indentation determines program flow The answer is you don t There are two types of region indentation commands intelligent ones that ask your major mode s indentation engine for advice something that works well with lan guages like TML or C and plain fixed width indentation for the rest Key and Command Description TAB Indents a line or region as per the major mode C M Indents using major mode s region indent command C x TAB Rigidly indents The Theory of Editing I
137. l commands sort lines except the lone paragraph com mand Command Description M x sort lines Sorts alphabetically M x sort fields Sorts field s lexicographically M x sort numeric fields Sorts field s numerically M x sort columns Sorts column s alphabetically M x sort paragraphs Sorts paragraphs alphabetically M x sort regexp fields Sorts by regexp defined fields lexicographically M x sort lines sorts in ascending order but if you call it with a universal argument it will reverse the sort order When you sort by line Emacs will call out to sort as it is much quicker unless you are on Windows in which case Emacs does it internally Lexicographic and numeric Lexicographic sorting is how most sorting algorithms typically work They look at the character code for each character and sort by those That works fine for most things except numbers Lexicographically the number 4 comes after the number 23 because the ordinal of 4 is greater than the ordinal 2 in 23 The Theory of Editing To sort your numbers correctly you must use M x sort numeric fields You can sort lexicographically or numerically using m x sort fields and M x sort numeric fields You must pick a column though To do this pass a numeric argument starting from 1 to sort by that column Columns are whitespace separated one or more whitespaces together signify a column delimiter So to sort the third column type M 3 M x sort fields You can
138. l quickly reach a point where you jump from buffer to buffer without so much as glancing at the minibuffer because your primed intuition tells you that if you type c x b wc IDO will flex match to widgets c Helm excels when you don t know exactly what you re looking for or if you require additional contextual awareness of similar matches I recommend you enable wo mode for file and directory find ing and buffer switching by adding the following lines to your init file ido mode 1 setq ido everywhere t setq ido enable flex matching t The Theory of Movement Now when you find files or directories c x c f and c x d or switch buffers with c x b you will use 1wo s far superior completion mechanism Of course you are free to use Helm as well if you prefer I recommend you learn just a couple of 10 s extensive key bindings File amp Directory Switching These keys are only available when you run a command that requires you to pick a file or directory That includes c x c f and c x d respectively but it also includes things like file saving with c x C s Key Binding Purpose C s and c r Move to the next and previous match TAB Traditional non 1Do TAB completion RET Open selected match C d Open m x dired buffer in current directory Go to root directory Go to home directory Backspace Delete a character or go up one directory Buffer Switching Buffer switching is usually only encountered w
139. lace interface Whether you find it useful depends entirely on how well you know elisp or how willing you are to experiment and how often you find yourself doing complex search and replace To call an elisp form you use this format form Where form is the name of a function you want to call There are some rules you must follow if you want to call out to elisp The Theory of Editing Capturing groups are string types by default passing a string to an elisp function that expects another type like an integer will result in an error You don t need capturing groups if your function does not require them It is perfectly possible to replace a match with the sole output from a function You can only call one form so if you want to call more than one you must wrap it in something like progn or progi or use functions such as concat to concatenate the results from multiple functions into one Do not quote the capturing groups as they are passed as literal strings if you use N or numbers if you use N to Emacs s interpreter Here are a few example replacement strings you can try out Replace String Description upcase N Uppercases capturing group N format 2f N Casts N to a number and formats it as a decimal with two decimal points Although it s a powerful feature it is situational Most of Emacs s internal functions just about anything that does something interesting operate
140. lemental movement commands available to you and indeed to every editor are the humble arrow keys They work as you would expect and if you re new to Emacs I recommend you use them until you learn the more advanced movement commands As with other editors you can combine the arrow keys written as lt left gt lt right gt lt up gt and lt down gt with the control key to move by word Simultaneously the other navigation keys like page up and page down also work in Emacs Key Binding Purpose lt left gt Arrow keys move by character in all four directions C lt left gt Arrow keys move by word in all four directions lt insert gt Insert key Activates overwrite mode lt delete gt Delete key Deletes the character after point lt prior gt Page up and Page down move up and down lt next gt nearly one full page lt home gt Moves to the beginning or end of line lt end gt Once you re comfortable with the basics of Emacs han dling buffers splitting and deleting windows saving and opening files you should move away from using the navi gation keys Though they serve their purpose well they are The Theory of Movement too far away from the home row and moving your right hand away from the home row just to move the point around on the screen is time consuming By the way The page up down buttons will scroll up or down a screenful of text retaining 2 lines of text for context You
141. les intelligent indentation when you press RET Before Emacs 24 4 you had to rebind a key not difficult but not a good first impression either Controlling indentation is a tricky subject as it is heavily mode dependent Some modes like python mode cycle be tween possible indentation stops as indentation is semanti cally important in Python Other languages like C come with a battery of styles to appease everyone Unfortunately there is no silver bullet here Indentation is a messy business even in prescriptive languages like Python Some languages such as yam files are so strict the YAML readers won t parse files if the indentation is slightly The Theory of Editing off That makes customization hard or just impractical to implement and that means compromises for you the writer If the general advice I give here doesn t work first read the manual and only if that fails inspect the variables and functions exposed by the major mode RET Indenting New lines When you press RET Emacs will as I alluded to earlier in sert a newline character and then invoke the major mode s indentation engine For this to work you have to enable the minor mode M x electric indent mode Thankfully it is auto matically enabled in Emacs 24 4 for earlier versions you have to rebind the ret key global set key kbd lt RET gt newline and indent With electric indent Emacs now also checks if you type cer tain
142. like most minibuffer prompts this one also has TaB completion Color Themes If you dislike the default color scheme in Emacs then good news you can use a color theme Type m x customize themes to see a list of your installed color themes There are more available for free from Emacs s package manager or sites like Github To install a theme with the package manager open the package manager M x package list packages and go look First Steps for themes most will have the suffix theme and they act and install like normal packages Once you ve installed the themes you need use the M x customize themes interface to try them out You can override specific colors you don t like by using the regular Customize interface described in The Customize Interface Changes made in the Customize interface take precedence over the themes I should mention that you can have multiple themes active at the same time so make sure you are aware of this Getting Help As I mentioned earlier when I talked about keys Emacs is a sophisticated self documenting editor Every facet of Emacs is searchable or describable Learning how to do this is abso lutely essential to mastering Emacs The utility of knowing how to find the answers to questions is something I cannot over state enough I use Emacs s self documenting functionality all the time to jog my memory or to seek answers to ques tions I don t know I still haven t talked
143. like uniq or other command line tools that modify their input Although m amp is asynchronous that is it wont block Emacs until it terminates it is a rather poor choice for long running tasks It s far better to use M x compile The Practicals of Emacs Compiling in Emacs Calling out to shell commands is meant for quick one off commands and usually not something you regularly do over and over For that purpose you should consider Emacs s M x compile command that despite its name excels at more than just compilation Commands Description M x compile Runs a command and tracks errors M x recompile Re runs last command M g M n M g M p Jumps to next previous error global g Re runs last command When you invoke m x compile you are asked for a command and Emacs kindly assumes you re using make However you are free to replace it with any command of which you want to track the output unit tests compiling running a script you name it The main advantage of M x compile is the M x recompile as it re runs your last command Compile also tracks errors thanks to its pattern matching engine Like M x grep and M x occur the M g M nand M g M p commands will jump through a call stack or compiler error log provided their formatting matches one Emacs knows Everything from Python to most compilers are known to Emacs so it will probably work for yours too The Practicals of Emacs Shells in Emacs Instead of u
144. line Some minor modes are also displayed in the modeline but usually only the ones that alter the buffer or how you interact with it in some way Chapter 3 First Steps I use Emacs which might be thought of as a ther monuclear word processor Neal Stephenson In the Beginning was the Command Line Installing and Starting Emacs Before I get into the nitty gritty of installing Emacs you should check and see if it s installed already In most normal Linux distributions it is not therefore you have to be extra vigilant if it is it might be an ancient version Checking Emacs s version You can check Emacs s version by typing emacs y typing version 32 First Steps As of 2015 the upcoming version is Gnu Emacs 25 If your version of Emacs is version 23 x or older upgrade If it s 24 x or newer then that s fine If you re still on 23 x you can get by with what you have but my view is to always use the latest release Not so much for the bug fixes because Emacs is actually extremely stable but for the features and the fact that most package authors assume you re using the latest version Having said that if you re on a very obscure platform it may not be possible for you to upgrade at all If you re using XEmacs or another non cnu Emacs you re ally should switch Ten or twelve years ago XEmacs was leading the pack but cnu Emacs caught up and exceeded the capabilities of XEmacs a long time
145. ll center the point in the middle of the buffer Recursive Editing Recursive editing is an advanced topic When you enter recursive editing c r Emacs will suspend any on going command such as Isearch search amp replace or a macro and hand control back to you the user You are then free to continue editing and otherwise use Emacs as you would normally but at any time you can type c M c and Emacs will snap back to the earlier recursive step that you entered and resume from then on You can nest recursive edits as many times as you reasonably like and if you are in recursive editing you can see it in your modeline because square brackets appear You can force Emacs to abandon all recursive editing levels by typing esc Esc Esc Note that unlike most other things c g will not exit out of recursive editing So how do you use this in practice One example is realizing during Isearch or macro playback that you need to edit text send an e mail or otherwise temporarily suspend what you are do ing C r lets you do that When you are finished type c m c to resume where you left off before An extremely powerful feature it is worth knowing once you have mastered every thing else in this book Saving and Recalling Macros in Emacs are stored in a macro ring aconcept that you should recognize from other parts of Emacs like the kill ring and undo ring Creating a new macro automatically stores old macros in the macro ring
146. ll switch directions If you reach the end of the matches or if there are no matches in your search direction you can continue the search from the beginning or end of the buffer de pending on the directionality of your search by tap ping the direction key again The minibuffer will tell you if it wrapped the search around to the other side Isearch will also tell you what part of your search string failed to match and what parts didn t by highlighting the failed match in red Pick a match Once you are happy with a match you can terminate the search in two ways C g exits Isearch Terminates Isearch and returns to your original position If you have a search string with only a partial match it will first return you to the last known match RET picks the selected match This also terminates Isearch but it leaves you at the match you are at and it drops a mark at your original location so you can return to your former location with c u C lt SPC gt 8Although this will depend entirely on your color theme The Theory of Movement Isearch is so useful that I strongly encourage you to use it for movement as it is one of the quickest ways of moving around text in Emacs It is also one of my most used commands I use it hundreds of times a day if not more It takes a bit of practice to commit the Isearch behavior to muscle mem ory but it is so worth it It has two accessible keys c s and c r and it is visual a
147. llo insert name here After c M t insert name here Hel lof So c m t still works as you would expect The usefulness is apparent in code as well The Theory of Editing ages Seinfeld f 34 As you would expect Emacs transposes things correctly ages 34 Seinfeld f The behavior is different compared with m t Consider the same scenario as before but with m t ages 34 Seinfeldff The result is different indeed Instead of transposing the en tire balanced expression we swapped the words instead but left the symbols behind Other Transpose Commands You can also transpose other syntactic units lines para graphs and sentences and aside from transposing lines the rest are harder I think to justify learning right away The paragraph and sentence commands are unbound making them harder to use the only way to use them is to invoke them through m x The Theory of Editing Transposing lines with c x c t is useful however I use it fre quently to re order newline based lists and it s also useful for swapping around variable assignments changing the order functions are called and so on Filling and Commenting Filling If you write a lot of text you occasionally have to manually break paragraphs so the lines won t exceed a certain length You can use Emacs s fill functionality to do this for you ei ther manually or automatically as you write The fill com mand is
148. ly when you finish with P We call sets of keys that belong to a particular prefix key key maps which is how Emacs internally tracks the mapping between a key and a command In this case the key map c x 8 has a variety of utility charac ters used in writing or mathematics but not bound on most keyboards For instance c x 8 P will insert the paragraph symbol 9 c M is a tricky one for beginners Using what you ve learned above hold down control and alt and as you ll remember from the table above Meta is Alt but also shift The character is typically shared with First Steps a number on the keyboard number range and the implication here is you must type shift also If you don t press shift you re actually typing c m 5 on a US keyboard anyway It bears mentioning that this particular key is bound to a popular command M x query replace regexp and is an example of a key that you cannot type in Terminal Emacs because of the terminal s technical limitations and not Emacs TAB F1 F12 and so on are occasionally written like this but also in angle brackets lt tab gt lt f1 gt It s important you don t confuse TAB with the characters T a B I will only use the former notation to avoid ambiguities Hint If you re stuck or in the unlikely event Emacs has seized up or if you have typed in a partial command that you want to cancel press C g That s the universal bail me out command in Emacs
149. macro A keyboard macro in Emacs is very different from a Lisp macro and you should not confuse the two Macro recording is not a new invention Most IDEs and text editors have it but few have one as advanced as the one in Emacs Emacs s keyboard macros are especially powerful as almost everything is recorded There are few blind spots none of which you are likely to encounter and that is what sets it apart from pes and their mostly anemic macro recording Emacs s macro recorder is itself written in lisp That alone speaks to the power of extensibility that Emacs offers but it also reinforces the extent you can inspect and record changes made at a microscopic and macroscopic level in Emacs Basic Commands Key Binding Description F3 Starts macro recording or inserts counter value F4 Stops macro recording or plays last macro The Theory of Editing Key Binding Description c x andc x Starts and stops macro recording C x e Plays last macro You can begin recording with F3 and stop it with F4 The other two keys are not as accessible and are there for back wards compatibility with wizened veteran users of Emacs When you start recording you can stop by typing F4 or C x Or M x kmacro end macro You can also terminate the macro with the universal quit command c g Occasionally you may trigger an error in Emacs and that will also stop recording Examples include using M g M n go to next error when there are
150. mmand M x tab to tab stop will insert spaces or tabs to get to the next tab stop a concept that dates back to and hasn t been used since the era of the typewriter Personally I have no use for such a thing and certainly not on such an accessible key To bind Imenu to m i add this to your init file global set key kbd M i imenu Like most of Emacs s completion prompts Imenu only sup ports TaB style completion out of the box I recommend you read the next chapter and use Helm s Imenu support instead The Theory of Movement Helm Incremental Completion and Selection Minibuf 1 home C z Describe Function keeping session Commands forward paragraph symbol word same syntax whitespace button line list sentence to indentation char sexp Helm is an amazing package It s a generic framework for filter as you type completion that is you begin typing and Helm will automatically filter and show you what matches not unlike Isearch s real time incremental search What makes Helm so fantastic is that it comes with a lot of completion commands out of the box My personal recom mendation is that you follow the installation instructions be low and start using Helm right away Helm is a radical depar ture from Emacs s usual low key completion mechanism particularly if you already have a workflow that works for you but Helm s extensive selection of completion sourc
151. more useful Helm completion engines Key Binding Purpose C x cb Resumes last Helm command cC xc Invokes the command line utility find on the active buffer s current directory The Theory of Movement Key Binding Purpose C x ca Completes M x apropos results C x cm Completion engine for the man page program C x ci Lists completions sourced from M x imenu or Semantic xcr Interactive regular expression builder xchr Search Emacs topics in M x info x c M x List completions sourced from m x x c M s o Use Helm to match m x occur patterns x c C c g Show matches from Google Suggest Some of the Helm commands have positively byzantine key bindings like c x c c c g to show Google Suggest matches Even by Emacs standards they re obtuse Learning Helm will greatly improve your Emacs experience It comes with a powerful fuzzy search and a large range of useful completion mechanisms It also has its own burgeon ing ecosystem of third party packages The interesting thing about Emacs is the unexpected productivity improvements you ll get from things like the Google Suggest completion mechanism Why switch to a web browser and search in the browser when you can do it in Emacs and get as you type suggestions from Google The Theory of Movement IDO Interactively DO Things Minibuf 1 home U scratch Bot of 191 5 0 Anau Find file usr share dict eng lish american englis 2 sh british english As I talked
152. must be viewed in a window in order to be dis played to the user and for the window to be visible to the user it must be in a frame Note Think of it as a physical window having a frame each frame made up of window panes In Emacs you are free to create as many frames as you like and in each frame you re free to split and tile that frame into The Way of Emacs multiple windows If you use a large screen monitor and who doesn t these days it is very beneficial to use Emacs s tiling system to show multiple buffers on the screen Modeline Echo Area and Minibuffer Terminal File Edit Options Buffers Tools Minibuf Help interactive insert UUU F3 scratch All L4 Lisp Interaction insert hello worldff The figure above is an example of a Terminal Emacs session Emacs uses the modeline to communicate facts about Emacs and the buffer you re in The modeline looks like this UUU F3 scratch All L4 Lisp Interaction There s a lot of information conveyed in a fairly small area What you should care about to begin with are the name and modes In this case the buffer is named scratch and the ma jor mode is Lisp Interaction Most editors have a similar con cept known as a status bar All sorts of optional information can be displayed in the mod eline laptop battery power the current function or class you re in what source control revision or branch you re us ing and much more
153. n an ideal world pressing taB with an active region is all you need to re indent it Unfortunately Emacs might not support that or in some programming languages it is not physically possible to determine the correct indenta tion Pressing TAB follows most of the same rules as line indentation Emacs attempts to indent according to the indent line function and it falls back on simply inserting TAB characters or whitespace if you disabled indent tabs mode Typing c m explicitly indents the region for some modes it works identically to TaB and in others it doesn t If you give the command a numeric argument it will indent the region to that column i e the number of characters and Emacs will also use your fill prefix if you have one and fill the text accordingly c M is occasionally useful as it respects your fill prefix However if you want to indent a fixed number of columns you should use c x TAB C x TAB explicitly indents the region a certain number of columns It also takes negative and numeric arguments However if you don t pass an argument Emacs will en ter an arrow key driven indentation mode that lets you interactively indent the region with s lt left gt and S lt right gt Sorting and Aligning Both sorting and aligning text are common enough actions that Emacs has its own set of commands that do both The Theory of Editing Sorting Sorting in Emacs works a lot like the command line utility sort Al
154. n interesting feature When you type c x Emacs will take every character on the current line up to point and make it the fill prefix A fill prefix is as the name implies inserted before the lines when you fill a paragraph with m q To remove the fill prefix place your point on an empty line and type C x The Theory of Editing You can tell Emacs to automatically fill text as you write by enabling M x auto fill mode I wouldn t use it in program ming modes it doesn t work well and limit its use to text modes Commenting If it was hard to write it should be hard to understand If you don t agree with this controversial yet remarkably com mon trope about code commenting you can use Emacs s comment commands to automate the tedium of comment ing and uncommenting Key Binding Purpose M Comment or uncomment pwim C x C Comment or uncomment line M x comment box Comments the region but as a box M j C M j Inserts new line and continues with comment on a new line The two you are most likely to use for in situ commenting are M and c x C If you type m Emacs will insert a comment at the end of the line the point is on and if you re on an empty line Emacs will indent the comment according to the major mode s indentation rules M given a region will toggle between commenting and uncommenting it The command c x C is new in Emacs IDWIM stands for Do What I Mean anothe
155. n type it That s slow and that slow ness adds up as we often spend as much time moving around as we do editing text You should only use character movement when it s the most efficient command available Moving by word is great but that won t help you if you want to move 2 characters into a word The four basic movement commands are Key Binding Purpose C f Move forward by character C b Move backward by character C p Move to previous line C n Move to next line As you can see mnemonically the assignments make sense p for previous b for backwards and all are bound under the c modifier You can apply universal arguments to the character keys and they will work as you expect Type c 8 c f and you will move the point forward eight characters You can even combine the negative argument to reverse the direction The Theory of Movement of the command that may not make much sense with movement keys but some commands come with a forward and backward command Most act in just in one direction forward that is and the negative argument is the only way to change this direction Learning Emacs s own movement commands as opposed to using the navigation keys to the right on your keyboard makes sense when you look at how Emacs s other move ment commands work I see experienced Emacs users execute choreographed sequences of commands to do interesting and complex actions only to stop dead in their
156. ncluding Window configurations and framesets You can store and recall the layout of your window configuration though I would argue there are much better tools such as M x winner mode I talked about in Window Management for the job Framesets are identical to window configurations but hold information about Emacs s frames instead Points The location of point is another thing you can store in a register If you are used to line based bookmarks from other wes or editors these are the closest equiv alents in Emacs Unfortunately the key bindings as you will see below diminish their usefulness Numbers and text Plain text is also storable that is partic ularly useful if you want to insert more than one piece of text making the kill ring a less ideal candidate You can also store numbers though the only distinction be tween text and number is the ability to use simple arith metic addition on a register containing a number The Theory of Movement Key Binding Purpose xr n Store number in register xr s Store region in register x r SPC Store point in register X r Increment number in register xr j Jump to register xri Insert content of register x rw Store window configuration in register xr f Store frameset in register A register is a single character only When you want to store or recall something you are asked for a single character to query Before Emacs 24 4 you had no real way of knowing wha
157. nd the behavior changes You can optionally specify either or works like a shell s file glob pattern and Emacs inserts all marked files as one long argument to a single command echo Prints american english british english Whereas echo Prints american english british english The output if there is any is printed in the echo area if it is only a few lines Otherwise it is redirected to a dedicated buffer called she11 Command Output The Practicals of Emacs Working Across Directories A common thing indeed how do you mark files in foo but also foo bar The answer is the i command Typing i on a directory in dired inserts it in the same dired buffer as a sub directory That means you can use the same mark and flag commands across dired directories provided they are in the same dired buffer You can collapse a sub directory mean ing commands won t apply to it while it is collapsed with By inserting multiple directories into a shared dired buffer you can not only glance at multiple directories at the same time but you can also work on them as though they were one large directory This is another powerful but underutilized feature in Emacs There is another approach However typing i is tedious and won t work well if you recursively want to apply a dired or shell command To get around that problem you can use Emacs s find wrap per commands I consider these commands combined with
158. nd instantaneous There are no distrac tions and no ceremony no modal dialog that pops up and obscures your buffer no fiddly radio buttons to change the search direction no mouse needed and no tabbing required to operate it either Case folding By default Isearches are not case sensitive low ercase searches will match uppercase and mixed case However when you use one or more upper case letters in your search Emacs will automati cally switch to a case sensitive search It s called case folding This is another one of those strange Emacs features that nobody would think to implement elsewhere It s also more useful than you would think You might be looking for an uppercase string but your search string doesn t have to be And if you really need case sensitivity all you have to do is spell out the uppercase or mixed case name and Emacs will only look for literal matches Of course if you are looking for only lowercase matches but no upper or mixed case matches then you have no choice but to The Theory of Movement disable case folding or use Isearch s toggles to temporarily enable case sensitivity If you prefer you can disable case folding entirely M x customize option case fold search RET Once you start using Isearch you ll want to use its history formally called search ring features more Isearch Key Binding Purpose M n Move to next item in search history M p Move to previous item in search
159. nd line utilities In this case it is The Practicals of Emacs usually 1s al but you can change the switches used by cus tomizing dired listing switches Microsoft Windows If you use Microsoft Windows then don t worry Emacs includes a 1s emulation layer written in elisp Instead of calling out to 1s Emacs will instead query the operating system directly The end result is a seamless interface that works across platforms As I talked about earlier the concept of The Buffer and Emacs s augmentation system is a powerful and pragmatic way of talking to external programs When Emacs calls out to 1s the output is inserted into the buffer the dired mode activated and the text augmented with highlighting and hyperlinks and other hidden properties to help Emacs navigate the text mechanically The major mode itself supplies the key bindings so that pressing RET on a file opens it Indeed as with any buffer you can copy the output of dired as it is basically plain text Most Emacs beginners and even intermediate users never really get to grips with dired Most never get beyond navi gating directories with it which is a shame because behind its simple exterior is a very complex and efficient system for file and directory operations Indeed there are more than 100 dired commands alone The Practicals of Emacs Navigation Navigating dired is fairly straightforward and since it s a buffer all your usual n
160. ndy if you want to track down and disable errant changes M x customize themes Shows a list of installed themes you can switch to I encourage you to use the Customize interface to configure Emacs It only has a subset of things you can or want to change but it s enough to get you started on the road to personalizing Emacs As you continue to use and personalize Emacs you may even tually reach a point where your init file is unmanageable When that happens it s common to split up your changes into groups of related changes However this is a low prior ity task until you re comfortable and your init file splitting at the seams with Emacs Evaluating Elisp Code Frequently you will find or write snippets of elisp code on the Internet and you ll want to evaluate it closing and restarting Emacs every time is a chore There are a number of different ways of doing this and I have only shown a few of the different methods available to you First Steps You can read Evaluating Elisp in Emacs for a thorough study of the subject Restarting Emacs is the simplest way which I recommend if you have broken something in Emacs or if you want to be sure things work in a fresh environment M x eval buffer will evaluate the entire buffer you re in This is what I use to evaluate something M x eval region evaluates just the region that you have marked important You must remember that not all things will be re evalu
161. next suggestion is to experiment Keep referring back to the book until it s muscle memory keep experimenting The Theory of Movement with different combinations and train your brain to recog nize patterns It s all about muscle memory and pattern matching knowing that if you do this command you ll get that outcome Nobody mastered Emacs overnight and Emacs mastery is a red herring anyway it means a hundred things to a hundred people Over the course of the chapter I showed you how to look things up using Emacs s internal documentation particu larly apropos c h and the describe system and that more than anything will help you master Emacs Forgetting the name of a command or the key it is bound to is immaterial if you know how to look up the answer in Emacs My final advice is about experimentation Every time you do something that you think you can do ina smarter or more efficient way have another read through the book or search the Internet for advice Most of my own techniques and workflow grew organically as I realized that particular problems I kept facing had solutions other than the naive manual way Chapter 5 The Theory of Editing An infinite number of monkeys typing into Gnu Emacs would never make a good program Linus Torvalds Linux Kernel Coding Style Docu mentation Editing in Emacs is perhaps even easier than learning how to move around effectively in Emacs Most day
162. ng alignment rule applies So if there is a rule that aligns string constants like in HELLO_WORLD_CONST Hello World then its section would be all consecutive lines that match that rule There are many built in alignment rules in Emacs and when you call M x align on a region of text Emacs scans the align ment rule list and finds the first one that matches all the cri teria in the rule list major mode alignment regexp to try and align and so on Unfortunately the alignment rules are hard to read and understand and in practical terms that means the feature is not as useful as it could be Each align ment rule in Emacs stored in align rules list requires a deep knowledge of regexp and a desire to peel apart the lay ers and figure out how the rule works The Emacs maintain ers missed an opportunity here by not requiring doc strings for every alignment rule that explain how they work The benefit of M x align current is that you don t have to mark a region first It figures out from the line the point is on what rule applies and applies it to neighboring lines too if they also match that rule The Theory of Editing Here are some of the built in rules in Emacs organized by major mode Python You can columnate assignments like so notice the alignment of UNIVERSE _ANSWER_CONST 42 UNIVERSE_QUESTION What is The Answer Lisp You can columnate alists in much the same way as the Python example
163. ng around with just the arrow keys like other editors Let s talk about each command in turn as their simple actions belie their complexity c x C f Find file Opening a file in Emacs is called finding a file or even visit ing a file Having said that it s perfectly fine to say open also The reason is that Emacs really doesn t distinguish between opening an existing file and creating a new file I use the terms interchangeably So if you type c x c f and enter tmp hello world txt Emacs will visit it whether it s there or not if it isn t an empty buffer is shown instead Major mode load order When you visit a file Emacs will pick a major mode Most editors make a lot of assumptions about file extensions that tRequired in Terminal Emacs The Theory of Movement you cannot easily change Emacs supports an array of detec tion mechanisms that can all be changed to suit your needs They are listed here in the order they are applied File local variables are variables that Emacs can enable per file if they present in the file They can appear as head ers mode mode name here my variable value or footers Local Variables mode mode name here my variable value End Emacs will also look at commented lines using that ma jor mode s comment syntax It is worth knowing that file variables read into Emacs are local to that file s buffer meaning other buffers are unaffected by it That m
164. ng typos as they occur Fixing mistyped characters with c t is a useful time saver as it saves you the effort of deleting both charac ters and retyping them M t Transpose Words Transposing two words with m t works as you would expect when the words are plain text like this Hello flworld After m t World Helloff Like transposing a character with c t the point moves for ward as though you had typed m f M x forward word and that means you can pull a word to the right The Theory of Editing Where m t really shines is when you use it with source code In What Constitutes a Word the m f and M b movement com mands ignore symbols in the direction you are moving in and m t behaves the same way Consider this example Python code where we have a dictio nary a key value hash map names Jerry ff Seinfeld Cosmo Kramer With the point between the key and value a call to m t is pure magic names Seinfeld Jerry Cosmo Kramer As you can see the key and value swapped places but the symbols remained in place Repeat it again and Emacs will continue and swap Jerry with Cosmo repeat it once more and you swap Jerry and Kramer How Transposing Actually Works The m t command is intrinsically linked to the M x forward word m f command Greatly simplified Emacs will call m f two times once The Theory of Editing with a negative argument to get the left side word to
165. ning the price to sort by The result looks like this Price Product 2 08 Americano 2 30 Macchiato 3 50 Cappuccino 4 0 Caramel Latte The Theory of Editing Sorting by regular expression is not something you will need to do often but when you do it is a powerful tool One important caveat is that it is possible to partially sort a line if your search term looks like this M x sort regexp fields Record Key 1 And if you sort the original text the output looks like this 2 00 Cappuccino 2 3 Caramel Latte 3 58 Americano 4 08 Macchiato Note that we have sorted the first column yes but the second column remains unchanged That is to say we have sorted the prices but not the associated products Be careful Aligning Text alignment in Emacs encompasses both justification and columnated text In fact the alignment engine in Emacs is so sophisticated that it is able to automatically align and justify code based on regexp patterns Command Description M x align Aligns region based on align rules The Theory of Editing Command Description M x align current Aligns section based on align rules M x align regexp Aligns region based on regexp The alignment commands work on regions which by now you are familiar with or sections a made up concept unique to some alignment commands like m x align current A sec tion is a group of consecutive lines for which the first matchi
166. niver sal arguments Understanding that Emacs s command states are merely numbers is a handy thing to know because you can also pass arbitrary numbers to commands A lot of Emacs hackers First Steps would write C u 10 a to print 10 characters but there s a much easier way By the way When you press a key say the a button on your keyboard how does Emacs write it on your screen The truth is there s a special command called self insert command that when invoked will insert the last typed key Having this com mand adds symmetry to keys and commands it makes your regular keyboard characters behave in exactly the same way as all other commands in Emacs And that also means keyboard characters and hence self insert command are subject to the ex act same rules as all other commands They can be unbound rebound and otherwise modified by you Bound to key binding c to c 9 are the digit arguments But they re bound to more than just that row of keys to maintain what I personally call the tempo of typing but more on tempo below Here are the various ways you can pass digit arguments to a command Key Binding Notes C u Digit argument 4 C u C u Digit argument 16 C u C u Digit argument 4 n First Steps Key Binding Notes M to M 9 Digit argument o to 9 C to C 9 Digit argument o to 9 C M toc M 9 Digit argument 0 to 9 C Negative argument M Negative argument C M Ne
167. nt to save a buffer to a different file akin to Save As in other editors you can use the command c x C w to write to a new file Saving all files You can type c x s and are asked in turn to save each unsaved file C x C c Exits Emacs You can exit Emacs or just terminate your connection to it if you are using Emacs in client server mode but Emacs will only exit after asking you if you want to save unsaved files You have several options when Emacs asks you to save a file Key Binding Purpose Y or yes Saves the file N or DEL Skips current buffer q Or RET Aborts the save continues with exit C g Aborts save and the exit Save all remaining buffers d Diff the file on the file system with the one in the buffer Most of the commands above are self explanatory Emacs will traverse the entire list of unsaved files but not all unsaved buffers As you may recall from earlier it is possible to have buffers that are not attached to any one file And if you try to exit without saving Emacs will always ask you one last time if you want to proceed The Theory of Movement c x b Switch Buffer If you edit more than one file at a time or switch between documentation buffers or mode specific buffers such as Python s shell knowing how to switch buffers quickly and efficiently is very important Like alt TAB in most window managers Emacs will remem ber the last buffer you visited so that when
168. o match all quote symbols That makes it possible to transform or merely find as these commands also work in regexp Isearch or Occur text bol stered by Emacs s understanding of the syntax of your major mode Determining a character s syntax class Emacs s Unicode support is fantastic and as part of its extensive Unicode support you have the option of inspecting any character of your lik ing using C u M x what cursor position To use it place your point on a character you want to inspect and either run the command or type C u c x You will see an array of information in cluding syntax class font lock Unicode name and much more There are several types of capturing groups available in Emacs Constructs Description 1 to 9 Inserts text from group N The Theory of Editing Constructs Description 1 to 9 Inserts text from group n but cast as an integer This is only useful in lisp forms Prompts for text input from user Inserts a number incremented from o amp Inserts whole match string The N capturing groups are of little use outside of an elisp form But is useful as it lets you replace matches with strings that you enter manually The group inserts a num ber starting from o that increments by 1 after every match Finally amp simply inserts the entire match string Invoking Elisp You can call out to elisp functions from within the replace portion of the search and rep
169. ocks of text as a paragraph You can alter the behavior of the paragraph commands so leading spaces mark the beginning of a new paragraph by running M x paragraph indent minor mode The paragraph commands are useful in programming modes also A lot of developers group lines of code together and sep arate them from each other with blank lines making them an ideal candidate for the paragraph commands The Theory of Movement Moving by Sentence The sentence commands share symmetry with the line com mands replacing the c modifier with m Key Binding Purpose M a Move to beginning of sentence M e Move to end of sentence Like a paragraph the definition of a sentence is a house style that varies but Emacs assumes you begin your sentences with two whitespaces after a period This is one sentence This is another You can alter this behavior by customizing with m x customize option the following variables Variable Name Purpose sentence end double space Non nil means a single space does not end a sentence sentence end without period Non nil means a sentence will end without a period sentence end without space A string of characters that end a sentence without requiring spaces after The one you are most likely to customize is sentence end double space The Theory of Movement Moving by Defun The word defun is another piece of Lisp arcana that stands for define function and in Emacs you will see it in pl
170. of explaining and the terminology Well it s jumbled Visual lines A visual line is defined as What You See If you open a file and a long line spans three wrapped lines in your buffer then you have three visual lines each of which is treated as a separate and distinct line by Emacs even if the underlying file has just one The Theory of Movement Logical lines A logical line is the opposite of a visual line Logical lines are governed by the content of the buffer and nothing else word wrapped or not one long line in a file is treated as one long line in Emacs Screen lines In some parts of Emacs s documentation you may see the term screen lines used in conjunction with logical lines A screen line is identical to a visual line and the terms are used interchangeably Historically when Emacs wrapped a long line the c p and c n commands for moving up or down a line didn t change A long line called a logical line wrapped into three lines called visual lines would still count as a single logical line for moving up or down by line the end result is that you couldn t use the line commands to move by visual lines Whether it was The Right Thing was a polarizing thing indeed You either loved it or you altered Emacs And most people altered Emacs The end result is today in the latest versions of Emacs the previous next line commands move by visual lines You can switch to the old be havior by typing M x customize
171. off Instead the items you just undid were added to the undo ring as redo records That means when you undo again you will actually undo redo the actions you just did until you get to the state you were at when you last stopped then Emacs will undo the rest of the changes in your buffer This means it s next to impossible to lose undo history as the act of undoing is itselfan undo able action That means you can undo a few things say rewriting a paragraph in a docu The Theory of Movement ment you re writing only to realize later on that actually you liked the old text better In other editors your undone changes would be gone forever as they have linear undo lists in Emacs you simply undo your newly written paragraphs until Emacs returns your buffer to the state it was in before you did your last undo Confused That s okay It took me a long time to under stand how this would work out in practice As it s impossible to really lose any data with the undo ring it s easier to just experiment but remember that Emacs will keep undoing things from the ring as long as you keep undoing commands one after another Only by breaking this undo cycle will you be able to redo the undone changes And the easiest way to break the cycle is by simplifying moving your point Here s a simple example It s not how Emacs s undo ring ac tually retains undo information it s rather more complex than that but I t
172. om ffarticles id 10 After zapping to http www example com ff id 10 And like the kill commands from earlier it also appends to the kill ring This is particularly useful as you can combine The Theory of Editing it with both kill commands and negative amp numeric argu ments to control the amount of sequential zaps to do and the direction to do it in Zap alternative There is a third party package called zop to char that kills to the character but does not include it Look for it in the package manager Many feel the zap command should kill up to the character you type and not include it I m fine with the default be havior but you may not be For me it is a quick way to kill text in conjunction with other commands so I don t mind that it is inclusive Spell Checking There are several ways of spell checking in Emacs and they all serve different use cases Spell checking in Emacs is surprisingly not performed by Emacs itself For Linux the choices are aspell and ispell and Emacs will choose aspe11 over ispell as it is faster and more modern Keys and Commands Description M Spell checks word at the point M x flyspell mode Minor mode that highlights spelling errors M x flyspell prog mode As above but only highlights strings and doc strings in code M x ispell buffer Runs spell check on buffer M x ispell region Runs spell check on region The Theory of Editing Regardless of which spell checker
173. on isn t actually active and work anyway so be careful As always I encourage you to learn Emacs s own commands in time but if you are overwhelmed you can use the mouse to click drag selections or use the arrow key selection with S lt arrow key gt Selection Compatibility Modes To ease the transition to Emacs there are several helper modes you can enable to mimic the behavior of other editors Emacs enables one or two of them by default now as part of their drive to modernize Emacs My personal recommendation is to start off with what you know and slowly wean yourself off the compatibility modes as you improve your Emacs skills M x delete selection mode When the region is active and you type text into the buffer Emacs will delete the selected text first This behavior mimics most other editors To enable or disable it use the customize interface M x customize option RET delete selection mode The Theory of Movement shift select mode variable enabled by default Shifted motion keys both traditional navigation keys like the arrow keys and Emacs s own commands activate the region and extend it in the direction you are moving The shift selection works differently from setting the mark with c lt spc gt When you shift select a region any non shifted movement command will deactivate the region Like delete selection mode this functionality mimics the behavior in other editors For instance S lt le
174. only sort by one column and as I mentioned earlier each column must be whitespace delimited To alter the col umn delimiter you must use M x sort regexp fields Sorting by columns with m x sort columns is the only way to sort by more than one column and then only successive columns To use it place the point and mark in the begin ning and end columns you want to sort and all lines from point to mark are then sorted If you find yourself in need of sorting things not delimited by whitespace you have to use M x sort regexp fields This command is rather complicated as it requires a good work ing knowledge of elisp it is also easy to only partially sort a region and that will mess up your text Consider this csv file of products Price Product 3 50 Cappuccino 4 0 Caramel Latte 2 08 Americano The Theory of Editing 2 3 Macchiato You cannot sort this data with the other sort commands as they won t work at all the data is not whitespace delimited To sort this we need M x sort regexp fields Emacs s internal sort routine needs a key that is what it uses to sort such as a field and a record which is typically the whole line Here is how to sort the example above M x sort regexp fields Record 1 4 Key 1 This first defines the record as two capturing groups one for each column separated by a comma The next step is to pick the key in this case the first column contai
175. ook at a few examples c d calls a command named delete char To invoke it hold down control and press d As the key is a complete key it will call the command delete char and immediately delete the character next to point c M d is similar to the example above but this time you must hold down both control and meta before you press d Let s try a few prefix keys Prefix keys are basically subdivi sions a way of grouping keys and increasing the number of possible key combinations For instance the prefix key c x has several dozen keys bound to it c x is a prefix key you will use all the time First Steps c x C f in Emacs runs a command called find file The way to interpret it is to first hold down control and then press and release x In your echo area Emacs will dis play after a small idle period of about a second c x with a dash at the end which is Emacs s way of telling you that it expects additional keys Finally type c f which should be easy for you to do now hold down control and press f To type c x c f you don t have to release the control key between each key keeping contro pressed helps you maintain something I call tempo which I will talk about later c x 8 P has two prefix keys first c x and then 8 which is a subcategory to C x So 8 on its own wouldn t do any thing it would just print the number 8 nor would c x or even C x 8 both are still prefix keys The key is complete on
176. option RET line move visual Adding to the complexity is the addition of Visual Line Mode a minor mode that builds on the concept of visual lines with additional functionality Visual Line Mode wraps by word boundary resulting in cleaner word wrapping like what you d see in a traditional word processor The minor mode will also disable the fringe indicators The Theory of Movement Additionally Visual Line Mode replaces a number of move ment and editing commands with visual equivalents c p and c n will behave as they do in default Emacs installations with the line move visual option enabled Furthermore commands like moving to the beginning and end of a line with c a and c e now work on visual lines instead of logical lines The kill command bound to c k but we haven t covered that command yet will also work on visual lines If you want this behavior and I encourage you to try it out and see if it fits your workflow you can enable it globally with M x customize option RET global visual line mode or in a buffer at a time by typing M x visual line mode What if you don t want word wrapping You can toggle word wrapping called truncation in Emacs with M x toggle truncate lines Moving by Word Like character movement moving by words is almost identi cal the mnemonics are the same for backward and forward character replacing only the c modifier with m Key Binding Purpose M f Move forward
177. or s behavior that you don t like that you can simply change it indeed a whole book could be written on the subject of changing Emacs First Steps Throughout this book I will make suggestions of things to change Where possible I will use the Customize interface in stead of the typical approach of suggesting elisp snippets If you want to change Emacs you have two choices Use the Customize interface as it s built in and designed to be user friendly I say that but a lot of people find it cumbersome and hard to use I think that s a bit unfair it s utilitarian and has to support a lot of arbitrary ways of configuring fairly complicated features Not everything is supported by Customize Since you need to write elisp to change variables and because of the data as code paradigm usr uses you will find that Customize can write elisp that it s been shown how to write and then only for specific options That makes it a virtual impossibility to generalize an interface across all of Emacs s many many settings But most of Emacs s built in packages support the Customize interface and a lot of third party packages do too I would strongly recommend you use the Customize in terface where possible until you re comfortable writ ing elisp Write elisp to alter what you want to customize This is the most powerful option but also the most complicated You ll have to learn elisp it s not too hard and writ
178. ore it has encoun tered a word character Moving forward again does not take us back to the end of the line as we are already at a word print add_two num_table 10f So you might be wondering why this is a good thing For starters you can follow up the original m b with m d to kill the number 19 and because of the asymmetry you don t kill the symbols but much more on the kill commands later Another reason is that it just does not make sense to think of a word as separated by just white spaces it raises too many questions What if there are many whitespaces in a row and what about punctuation and symbols When you have to navigate a mix of symbols and text like most source code is Emacs s behavior is perfectly sensible keep tapping M b and you move back consecutive words of text but you conveniently skip any symbols you encounter in the direction of travel The one thing people find confusing is the asymmetry the rules seem insensible but now that you know how Emacs moves its behavior should make a lot more sense The Theory of Movement Sub and Superword Movement If you edit a lot of code with camelcase you may want your movement and edit commands to treat each sub word delineated by a capitalized letter as its own word Simultaneously you may want the opposite that text written_like this which Emacs ss word movement commands usually but again this is all down to the syntax table and vagaries
179. ote I undid is still there If I type c I will undo my latest quote and the one I undid before would reappear The Theory of Movement Still confused That s normal It s a difficult concept to get and much harder to explain but most Emacs beginners will pick it up over time The main point to take away is that it s almost impossible to break the undo ring and lose information so go ahead and experiment Chances are to begin with you only care about undoing the most recent changes anyway By the way You can download alternative undo implementa tions for Emacs A popular one is Undo Tree Window Management Managing windows is another core skill you have to mas ter Honestly despite the chapter introduction saying it was rather complex the truth of the matter is it isn t there are only a few key bindings you need to learn What makes it complex or to some people downright infuriating is the reliance on windows in the first place and how to get used to the windowing concept Let s take a look at the key bindings you need to know about Key Binding Purpose Deletes the active window Deletes other windows Split window below Split window right C x WwW N FP 3http www emacswiki org UndoTree The Theory of Movement Key Binding Purpose C x o Switch active window These five keys are all you need to use split and delete win dows There are more commands as you ll se
180. oth email and source control systems is Emacs s client server mode Yes Emacs has a client server architecture Note The client server functionality is fantastic but I wouldn t spend too much time playing around with it until you re comfortable with Emacs ba sics The myriad advantages of Emacs s server mode are First Steps A persistent session means Emacs will re use the same ses sion instead of spawning a new distinct copy of Emacs every time It works well with ep1tor by opening the files in your shared Emacs session and automatically signalling the calling program when the session finishes Fast fileopening from the command line using the emacsclient binary The Emacs client will connect to the local Emacs server instance and instruct it to open the file To use the client server functionality you must explicitly start the server M x server start launches a server inside an already running Emacs instance The instance turns into a server when you type this there s no visual feedback per se that it s running When you exit this Emacs instance it will shut down the server also so if you want a server daemon you need the option below emacs daemon will run Emacs as a daemon It will call server start as above but will return control to your terminal immediately and run in the background waiting for client requests If you go the server route you cannot use the default emacs bi nary an
181. ound c Undo Undoing is acommon activity and it is bound to several keys C C _ C x u Edit gt Undo or even a physical undo button if your keyboard has it Which command you prefer is up to you I think c is the easiest to type but if your character set is not US or UK 2http www masteringemacs org article introduction to ido mode The Theory of Movement then you may prefer another Most beginner s guides will recommend you use C x u or even C _ but I find them harder to type than c Unlike other editors Emacs does not have a dedicated redo command and that has to do with Emacs s unique undo sys tem known as the undo ring Most editors feature a linear undo list you can undo and redo but if you undo and then change the text you will lose the undone steps they will be unrecoverable and lost forever In Emacs this is not the case Every action you take is recorded in the undo ring and this includes the act of undoing something Emacs will group certain commands together into one cohesive undo unit like typing charac ters or repeating the same command many times in a row Some events will always seal the undo record and start a new one Pressing RET backspace or moving the point around are three such examples Repeated undo commands will undo more and more things but if you break the cycle for instance by moving around or editing text Emacs will not resume from where you left
182. over your copyrights to the FsF to sub mit to it and most people can t or won t do that Therefore almost all packages appear on Melpa and Marmalade Thank fully the package manager will merge all the different list ings into one As the repositories are privately owned by volunteers they may go down temporarily or permanently so I would check the Emacs Wiki for a current list of repositories For now though you can add this to your init file It in cludes the official repository and two unofficial community maintained repositories setq package archives 14The Emacs Lisp Package Archive tshttp www emacswiki org emacs en ELPA First Steps gnu http elpa gnu org packages marmalade http marmalade repo org packages melpa http melpa milkbox net packages Now is a good time to make Emacs evaluate it Execute the command M x eval buffer with your init file as the current buffer Next type M x package list packages and Emacs should re trieve the package listings from all three repositories above When it s done a new buffer will appear listing all the pack ages Like a lot of ancillary buffers in Emacs this one is also hyperlinked Have a browse you can one click install the packages you care about from the detail page of a package Hint If you know the name of the package you can use the shortcut m x package install and enter the name in the minibuffer And
183. planation it s a Lisp term that today covers a wide range of commands that operate on balanced expressions Balanced expressions typically include Strings Programming languages being the primary exam ple of strings which are balanced expressions because they begin and end with or Brackets In most major modes brackets are considered bal anced as they have defined open and close characters and and and lt and gt The Theory of Movement Balanced expressions can span multiple lines multi line strings for instance and Emacs knows this Whether a particular set of characters defines a balanced ex pression will depend on your major mode and the major mode in turn will define these characteristics in the syntax table I talked about earlier Like the word and character commands these follow the same mnemonic as before but with a different modifier This time it s C M Key Binding Purpose C M f Move forward by s expression C M b Move backward by s expression The usefulness of these commands cannot be overstated Consider this Python example look where the point moves when you press C M f a k Hello World Foo Bar After d Hello World Foo Bar M The Theory of Movement Emacs knows that and in python mode is a balanced expres sion because of the syntax table and thus treats and as a balanced expression and immediately moves to
184. r and it attempts to complete the word at the point to one of those That does not make it useless it is still useful it s just that Hippie Expand is so much better To use Hippie Expand effectively you should replace DAb brev as the two though it s possible to use both really don t complement one another at all Add this to your init file to switch to Hippie Expand global set key remap dabbrev expand hippie expand Hippie Expand expands more than just words The variable hippie expand try functions list is an ordered list of expan sion functions Hippie Expand will call with the text at the point when you call m What I like most about Hippie Expand is the file name com pletion It works exactly like your shell s Tas completion The Theory of Editing you type M and Hippie Expand will try to complete the filename or directory at the point If you ever find yourself inserting absolute paths or relative file names in code config uration files or documentation Hippie Expand will make your life much easier Another great feature is its ability to complete whole lines It will fall back to word completion if it runs out of ideas and if you regularly write elisp then Hippie Expand will guess if the text at the point is a potential elisp symbol and automatically complete it for you also As with DAbbrev repeated calls to m cycles through all the potential matches but c m only shows compl
185. r modes and are not global Therefore you may get a different answer depending on the buffer in which you type the command Emacs does have a lot more describe commands but they re nowhere near as practical or useful for day to day use Knowing what you know now about the naming of de scribe commands and how to find commands by patterns it should be a trivial exercise to list all of them 17Hint apropos command is a good place to start Chapter 4 The Theory of Movement Escape Meta Alt Control Shift info gnu emacs Getting around and getting around efficiently is as impor tant as knowing how to edit text quickly and efficiently But movement in Emacs is more than characters in a buffer there s a host of supplementary skills that make up navigation like understanding Emacs s rather complicated windowing system I wouldn t expect you to remember and apply everything you learn here right away I ve laid things out so you can start at the beginning and work your way through picking up bits and pieces as you read The most important part as I ve stressed many times is to give it time and practice take a moment in your day to day life to ask yourself if there s a better way of solving a problem with which you are faced 74 The Theory of Movement Movement in Emacs is local regional or global Local move ment is what you do when you edit and move around text near to the point A syntactic uni
186. r way of saying Emacs will try to guess what you want to do The Theory of Editing 24 4 and toggles comments on the whole line the point is on c x C also works with a negative and digit argument Typing M j or C M j with your point in a comment makes Emacs break the line and insert a new comment In that sense it is identical to fill prefix This command is particularly use ful if you write a lot of doc strings as Emacs is generally smart enough to recognize comment prefixes that some doc string formats require It bears mentioning that the Emacs fill commands I talked about earlier understand and respect comment syntax so feel free to use M q in a comment If you are using the comment commands in a major mode that does not have the requisite comment variables set up see table below Emacs will ask you for a comment character to use when you first run the command Variable Name Purpose comment style Style of comment to use comment styles Association list of available comment styles comment start Character s to mark start of comment comment end Character s to mark end of comment comment padding Padding used usually a space between comment character s and the text All the variables above are customizable with m x The Theory of Editing customize option It is unlikely that you will ever have to change comment start or comment end as they are almost always set by the major mode authors comment style is
187. rching for words near where you want to go Tra ditional text editors and wes attach too much edifice and complexity to the ur but in Emacs Isearch nearly eliminates the visual clutter and context switching and hence you keep your tempo The Theory of Movement Occur Print lines matching an expression Occur home Acevedo s Achaean Achaean s Achebe Achebe s Achernar Acheson Acheson s Achilles Achilles s Aconcagua Aconcagua s U american english 1 of 939k 79 8 Fun 126 matches for foo in buffer american english 1799 Big 1800 Big 1855 Black 1856 Black 5327 sball 5328 sball s 17823 21789 21790 25397 25398 Occur mode is a grep like utility built into Emacs Unlike grep it has far fewer functions and will by default only op erate on the current buffer What makes m x occur great is its speed and that it comes with Emacs so you don t have to call out to an external process Occur will also preserve the The Theory of Movement syntax highlighting in its match results Whereas Isearch incrementally walks you through every match in a buffer occur will instead create a new buffer called occur with all the match results in it You can activate occur globally and from within Isearch it self Key Binding Purpose M s o Occur mode M s o Activate occur on current search string inside Isearch Unlike Isearch you re asked for a regular expression for which to search Occur mode searches
188. ry sophisticated directory and file manager seamless support for almost every major ver sion control system and thousands of other features large or small Important Conventions There are some important Emacs conventions that I need to talk about before we continue It s quite important that you memorize them or at least refer back to this page if you re in doubt They will crop up again and again in the book and elsewhere and knowing them is paramount if you want to make use of Emacs s extensive internal documentation This is not an exhaustive list of conventions used in Emacs or even in this book I will introduce specific terms and con cepts throughout the book though some terms transcend specific topics and are therefore important to know before hand The Way of Emacs scratch home Next Distrib Up emacs Top The Emacs Editor Emacs is the extensible customizable self documenting real time display editor This manual describes how to edit with Emacs and some U info emacs Top Top of 52k 2 0 info yas Narrow TEES LE All of 192 5 0 A n a The Buffer Most text editors and wes are file based they display text from a file and they save the text to a file That s it In Emacs all files are buffers but not all buffers are files If you want a throw away area to temporarily store snippets from a log file or manipulate text or whatever your reason you just create and name a n
189. s A lot of people use tools like ack for the ease of which you can include or exclude file patterns but Emacs thankfully automates that tedium I encourage you to browse the grep category with Customize and configure it to your liking M x customize group RET grep RET The Theory of Movement Using the Grep Interface Like I mentioned in M x occur you can re use the jump com mands The Theory of Movement Key Binding Purpose M g M n Jump to next match M g M p Jump to previous match As before they are global and work across buffer boundaries They are worth knowing as you can quickly and easily jump between matches in a grep buffer Emacs will open the files and jump to the right line if they are not already open and if they are Emacs will simply switch to the already open file Grepping in Emacs Like everything in Emacs it comes down to modes and the major mode for grep is named you guessed it grep mode What Emacs actually does boils down to is piping the output from grep to a buffer named grep followed by a call to grep mode When activated grep mode will highlight the matches and hyperlink them to the line number and filename so you can jump around If you look closely the output in a grep buffer looks identical to that of grep itself You can test this by opening a blank buffer c x b and then pick a name not in use and enter something like this my_file txt 10 This does not exist
190. s and the world through a speech interface that understands the con tent of what appears on your screen Emacspeak will change the voice characteristics of the speech engine to reflect different syntactic elements in source code or to emphasize layout fonts or graphical icons For blind Emacs users Emacspeak is a lifeline that has enabled them to continue working by using Emacs s many tools such as e mail or web browsing The fact that this functionality has been around for 20 years is in itself impressive but Emacs s ability to sup port this sort of transformational software is beyond inspiring Remote file editing Emacs s Tramp seamlessly lets you edit remote files using a variety of network protocols including ssm FTP rsync and more as though the files were local Shell access Emacs has a built in anst capable Terminal em ulator an Emacs wrapper around shells such as bash and a full blown shell called Eshell written entirely in elisp ORG mode A to do agenda project planner literate programming note taking and more application It is widely considered the best text based organizer ever 4http emacspeak sourceforge net s Transparent Remote file Access Multiple Protocol The Way of Emacs a feat only surpassed by the fact that people switch to Emacs just to use it And much more Official or unofficial support for almost every programming environment built in man page and info reader a ve
191. s the menu bar by pressing F10 If you don t see a user interface similar to the figure above it s most likely due to customizations made to your init file The quickest way to test this is to close Emacs and restart it with emacs q If that fixes things then it s definitely cus tomizations made to your Emacs Most starter kits assume gt ee you re reasonably familiar with Emacs and they often disable things like the menu bar and tool bar You are actually free to play around with Emacs now the arrows keys will work fine and combined with the menu bar you can open and save files Emacs will auto detect most file types and apply the correct major mode to it if it doesn t you may have to install third party packages which I will talk about later Keys The most important subject in Emacs Emacs is famous for two things its obscure keyboard incantations and that it s the kitchen sink editor that can do everything The comic strip xkcd humorously referenced that part of Emacs lore A much older joke is that Emacs stands for Escape Meta Alt Control Shift Nevertheless key modifiers are a big part of day to day Emacs use so being able to decode a string of keys is important 8http xkcd com 378 First Steps In Emacs there are several modifier keys you can use each with its own character Modifier Full Name C Control M Meta Alt on most keyboards S Shift Two more exist
192. s both a blessing and a curse You can re define live functions change variables left and right and you can query the system for its state at any time state that changes with every key stroke as Emacs responds to events from your keyboard to your network stack Emacs is self documenting because it is the document There are no other editors that can do that No editor comes close And yet Emacs never crashes not really anyway Emacs has an uptime counter to prove that it doesn t M x emacs uptime multi month uptimes are not uncommon So when you ask Emacs a question as I will show you how to do later you are asking your Emacs what its state is Be cause of this Emacs has an excellent elisp debugger and un limited access to every facet of Emacs s own interpreter and state so it has excellent code completion too Any time you encounter a LISP expression you can tell Emacs to evalu ate it and it will from adding numbers to setting variables to downloading packages Extensibility Extensibility is important but emphasizing that importance is difficult if you don t know the scope of possibilities in Emacs I ve included just a few examples of what Emacs can do or more importantly still what Emacs can enable people to do here The Way of Emacs A speech interface for the blind For 20 years Emacs peak has offered blind or visually impaired Emacs users a way of interacting with Emac
193. s runs Combined with native TRAMP support and the ability to redirect the output of commands straight into an Emacs buffer you have a tool that is versatile powerful and very much in the spirit of Emacs Eshell is more akin to shell mode than ansr term It does not support interactive programs like top preferring instead to open a dedicated M x ansi term instance to run those pro grams when you call them from Eshell a clever and prag matic solution to the problem Another important difference is that although Eshell is inspired by shells like bash it is in fact its own shell implementation with all the quirks features and limitations that go with it It must be said that Eshell is an elisp shell first and foremost as every command you type into Eshell is first filtered through Eshell s own emulation layer then through Emacs s own interactive commands and then finally through programs in your PATH or in the current directory For instance you can type dired to open a M x dired session in the current directory or find file todo org to open todo org in your currently running Emacs Chapter 7 Conclusion Emacs is the ground We run around and act silly on top of it and when we die may our rem nants grace its ongoing incrementation Thien Thi Nguyen comp emacs How do you master a text editor as diverse as Emacs The answer surprisingly is simple by knowing how to ask it the right questions As I
194. should be your first port of call when you re using a new major mode You will discover a lot of Emacs s functionality this way and it is absolutely imperative that you use this command What it doesn t do is list mode specific commands that are not bound to any key they are simply not shown M x describe function or C h f Describes a function An other command on the critical path to mastering Emacs Knowing what something does in Emacs and how to look it up is useful but so is being able to jump to the part of the code where it s declared Describing a function will give you the elisp function signature the keys if any bound to it a hyperlink to where it s declared and a doc string If the function is a command it will say it is interactive M x describe variable or C h v Describes a variable Like describe function this command is also important but perhaps less so as changing variables is not always easy to do for a beginner Nevertheless being able to read up on what a variable does is First Steps M x describe key or C h k Describes what a key binding does Of all the commands this is one of the most use ful ones to memorize and like M x describe function its a command you will use frequently If you re unsure what a key binding does simply enter the describe key interface and re type the key and Emacs will tell you what it does It s worth remembering that some keys come from major and mino
195. sing an external terminal emulator or running Emacs in a terminal just so you can use it with tmux or screen why not use Emacs as the multiplexer and use Emacs to run your shell instead Combined with tramp and Emacs s tiling window management and buffer support you can re place almost all common use cases of dedicated terminal em ulators There are three ways of interacting with shells like bash in Emacs One is a simple wrapper around an external existing shell like bash called m x shell another is a complete shell implementation written in elisp called M x eshell and the third is a terminal emulator called m x ansi term All three are very powerful and each attempts to solve the problem in their own special way Whichever one you use and you may well end up using more than one comes with a number of trade offs All three however use elisp to either communicate with an external program or to implement a shell in Emacs or to in terpret the terminal control codes needed to render complex interactive programs like top All three also use Emacs s pow erful buffer paradigm that by now you are quite familiar with to provide a unified interface for all three implemen tations The buffer paradigm is especially powerful here as the abil ity to communicate with external programs or directly with the operating system is part of what makes Emacs such a pow erful editor You gain all the editing and
196. t a semi formal term for commands that operate on a group of characters is a char acter word line sentence paragraph balanced expression and so forth Regional and local movement are similar but regional movement involves whole functions or class defi nitions if you are writing code or chapters and such con structs if you are writing prose Global movement is any thing that takes you from one buffer to another or from one window to the next The first thing a beginner sees is Emacs s penchant for creat ing windows when you view a help file when you compile a file or when you open a shell If you have never used a tiling window manager for that is exactly what Emacs is the idea of splitting and deleting windows may seem strange in other editors you may use split panes but you almost never change it to suit the task at hand In Emacs windows are transient they come and go as you need them You can save your window configuration and there are several ways of doing this but they were never meant to be immutable like so many editors set once and then never changed again You have to get used to this Now there are many variables you can use to fine tune Emacs s windowing behavior but you can t really tweak your way out of using Emacs s windows Some packages try to replace windows with frames with some success but they are essen tially hacks and I would recommend you avoid using them at
197. t occupies are listed followed by the function signature if you were to call the command directly from lisp And then finally is the documentation string describing the command All this information is dynamically generated when you call C h k The slight downside of c h k is that its intended audience are elisp hackers and not end users the doc string describes how the command works from a technical perspective and that usually means explaining how each argument and other technical minutia of little relevance to end users works But that s usually not a problem for a technically minded person even if you are not a lisp developer Describing commands If you have the name of a com mand such as vc dir you can use C h f and Emacs will describe what the command does C h m Finding mode commands If you run the command c x v d a new buffer appears show ing you the version status of your current buffer s repository things like untracked and modified files are shown here But The Practicals of Emacs how do you interact with it How do you discover how to use vc s status buffer The answer is c h m a help command that describes a mode It displays the documentation strings for all major and minor modes active in the buffer you called it alongside any keys unique to those major and minor modes In other words use this command to figure out what each major and minor mode does and what keys if any they expose So
198. t the registers contained unless you had a good mem ory that is but now Emacs pops up a preview window after register preview delay seconds default I second c x r sis the one I use most frequently It stores the region in a register simple and useful and c x r i which inserts the content of a register at point One important note about c x r iis that prior to Emacs 24 4 it would put your point at the beginning of the inserted text and not after like c y yank would That is now changed in Emacs 24 4 but for earlier versions of Emacs you must give it a prefix argument C u c x r i to place the point after You can store the point location with c x r spc but to jump to it you must use C x r j arguably c x r i should Do The Right Thing here and jump to the point if the register stores a point Instead Emacs inserts the internal point location which is not useful at all to anyone The Theory of Movement Both framesets and window configurations are storable but I never use them myself There are better packages out there like m x winner mode as I talked about earlier To store a number place the point before it and type c x r n To increment it by prefix numeric value default 1 type c x r and to increment it by an arbitrary amount give it a numeric argument and a negative one to decrement You can recall a number register with c x r i Both registers and bookmarks are useful and they serve two different purposes
199. th a hostname username and port the latter two are optional ssH config If you use ssh I strongly suggest you use the configuration file as you can store all the connec tion and credential details in an easy to remem ber name For more information type M x man RET ssh_config to read the relevant manual page in Emacs Finally to actually invoke Tramp you must call it from the root typing in mo mode will jump to the root and follow the format as above If you use ido mode as I recom mend you do see Buffer Switching Alternatives wo will auto suggest both protocols and configured hosts automati cally Note that Emacs will not initiate a remote connection until you enter the second like so ssh homer powerplant var log reactor 1log The command above connects to the server powerplant using ssh as the protocol and homer as the user It then opens The Practicals of Emacs the file var log reactor log You can omit the protocol and tramp will use the method protocol described in tramp default method I suggest you customize it and change it from scp to ssh or plink if you re on Windows The default directory Every buffer has a default directory variable The variable in elisp terms is buffer local Each buffer has its own default directory variable as it is local to just that buffer and not global like variables are by default in Emacs When you type c x c f in a buffer Emacs looks to d
200. the moon what they re saying is hold down meta and press x and the M x prompt will appear in your minibuffer that s the line at the very bottom of Emacs At this point you can type in the name of the command Try it enter lunar phases and press RET The lunar phases com mand will open a new window on your screen displaying tohttp home comcast net mmcm kbd SpaceCadet html tthttp sharpkeys codeplex com First Steps the lunar phases from today onward You can type C x 1 to hide the buffer Hint If you enter M x by mistake remember you can type C g to exit out again Emacs has built in auto completion support so pressing TAB will open a new window and list all the potential candidates As you type and press TAB Emacs will automatically narrow the list of candidates If your partially typed match only has one candidate left when you press TaB Emacs will complete the whole name for you You can also just press RET it completes like taB but with the added benefit of running the command if it s the only candidate left You may think m x is a special Emacs command but it s actu ally not It too is written in elisp and bound to a key just like everything else Commands and functions When I talk about commands I m talking about a type of function that is accessible to the user For a function to be accessible to a user notwith standing the ability to evaluate any expression in elisp it must
201. the power of dired to almost completely replace all direct use of find and xargs With dired s shell command support and extensive file operations I can do in Emacs what most people struggle to do well with find Its unique query lan guage makes it hard to find exactly what you want In Emacs you can find with broader strokes and mark what you need All commands take the output of find and build a dired buffer relative to a starting directory Emacs is clever enough to notice the relative paths in what was the filename portion of the buffer All commands in dired work as usual The Practicals of Emacs Commands Description find dired Calls find with a pattern find name dired Calls find with name find grep dired Calls find and grep find lisp find dired Uses Emacs and regexp to find files The first three commands call out to find the command line utility find dired like with the grep commands is the most basic one you have to give it a find pattern and a starting di rectory find name dired finds by shell glob patterns against the filename only starting in a particular directory of your choosing find grep dired matches all files but only displays the ones that match a pattern passed to grep Microsoft Windows Microsoft Windows has a choice of installing cross compiled binaries like GNUWin32 or Cygwin or using find lisp find dired The command find lisp find dired is Emacs s elisp imple mentation of find dired It
202. ther working the digit and neg ative arguments into their workflow but I find them immensely useful Things like changing the casing on a word I just typed are easily done by reversing the direction of a command by giving it a negative argument Maintain your tempo and avoid moving your fingers away from the home row Negative arguments add direc tionality to commands digits add repetition or change how a command works Discovering and Remembering Keys If you can t remember the exact command for something then Emacs can help Let s say you can t remember how to print the paragraph character but you do remember it s somewhere in the c x 8 key map then all you have to do is 12If you touch type a skill worth learning above all else First Steps append C h to any prefix key to get a list of all bindings that belong to that key map Typing c x 8 c h will display a computer generated list of keys and their commands This interface is hyperlinked and part of Emacs s self documenting help system Key Binding Prefix Command o o OW lt WnNnwWwDUVDVT AO yYvVA K Mm Hh a Above is a subset of the commands you see when you request the help page for c x 8 If you see just a character in the Bind ing column that means it ll print the character when you type that key However Emacs will also tell you if there are more prefix keys with further sub levels in this case c x 8
203. they don t work well I personally use shell mode for almost all my command line 2Thankfully you can use M x proced and M x man as replacements for both The Practicals of Emacs needs I use very few interactive terminal programs and when I need to I can use Emacs s M x ansi term for proper terminal emulation The upsides free form text editing and movement be cause shell mode is just a simple buffer outweighing the downsides GNU readline and defaults Most Linux distributions use GNU readline a li brary to provide basic command prompt func tionality like command history search and re place commands and other useful features They are by default Emacs key bindings If you know one you can mostly apply the same ones here and vice versa And that goes for general editing and movement commands too Here are some of the most useful commands Unfortunately they are all over the place in terms of bindings Keys Description M p M n Cycles through command history C lt up gt C lt down gt Cycles through command history M r ISearches history backward C c C p C c C n Jumps to previous next prompt C c C s Saves command output to file C c Co Kills command output to kill ring ese C 1 Lists command history C d Deletes forward char or sends D C c C z Sends stop sub job The Practicals of Emacs Keys Description TAB Completes at the point Both M p M n C lt up gt and C lt do
204. ticals of Emacs is it exposes you to commands you wouldn t otherwise con template using or even knew existed Perhaps you have a new need to say create a tag C x v s and if you re unsure of what it s called or what it is bound to or indeed if such a feature even exists in Emacs then c h may shed some light on it c h k Describe what a key does On the other end of the spectrum is having a key and not knowing what it does The command c h k takes a key bind ing and shows you what is bound to that command in the active buffer For instance c h k followed by c x v v shows you not only the name of the command but the doc string for that command Usually the text is descriptive and explains what the command does C x v v runs the command vc next action found in global map which is an interactive autoloaded compiled Lisp function in vc el It is bound to C x v v lt menu bar gt lt tools gt lt vc gt lt vc next action gt vc next action VERBOSE Do the next logical version control operation on the current fileset This requires that all files in the current VC fileset be in the same state If not signal an error The Practicals of Emacs Shown above is the key binding and the command it runs It also shows you where the command was found in this case in the global map because it is a global key and the library file containing the command Next all the keys it may have multiple bindings i
205. time And finally if you re an existing Emacs user but struggling to take it to the next level or maybe you just need a refresher course from the ground up then this book is also for you What You ll Learn Covering all of Emacs in just one book would be a Sisyphean task Instead I aim to teach you what you need to be produc tive in Emacs which is just a small subset of Emacs s capabil ity Hopefully by the end of this book and with practice you will know enough about Emacs to seek out and answer questions you have about the editor To be more specific I will teach you in broad terms six things What Emacs is about A thorough explanation of impor tant terminology and conventions that Emacs uses which in many cases differs greatly from other editors You will also learn what the philosophy of Emacs is and why a text editor even has a philosophy I will also talk about Vim briefly and the Editor Wars and what the deal is with all those different keys Getting started with Emacs How to install Emacs how to run it and how to ensure you re using a reasonably Introduction new version of Emacs I explain how to modify Emacs and what you need to do to make your changes perma nent I will introduce the Customize interface and how to load a color theme And finally I ll talk about the user interface of Emacs and some handy tips in case you get stuck Discovering Emacs Emacs is self documenting but what does
206. to Emacs s macro functionality There are many commands and you are unlikely to ever use most of them Learn more As always you can append c h toa prefix key and Emacs will list all the keys bound to that prefix Another way is to list all the commands with apro pos c h a the commands are all named kmacro The Theory of Editing Interactive Macro Playback Let s start out with the counters When you start recording Emacs will automatically initialize an internal counter to zero and every time you press F3 during the recording Emacs will insert the counter and then increment the internal counter by 1 There are of course many creative uses for the counter creating numbered lists is the most obvious Key Binding Description C x C k C a Adds to counter C x C k TAB F3 Inserts counter C x C k C c Sets counter C x C k C f Sets format counter C x C k q Queries for user input while recording The counter commands above do more than this c x C k c a adds a number to the counter and conversely giving it a negative number subtracts from the counter Both F3 and c x C k TAB insert the counter value and increments it by 1 but if you give it the universal argument C u it will insert the last number and not increment the counter very useful if you need the same number used several times in one recording Counter reset Counters are only reset when you explicitly set them or when you record a new macro The co
207. to character mode By default ansi term acts like a regular terminal emulator and not like shell mode or a typical Emacs buffer However you can switch between two different modes line mode which is like a typical Emacs buffer and character mode which is like a normal terminal emulator The default mode is character mode and that means most keys including keyboard characters and not just Emacs key bind ings are sent directly to the underlying shell program by passing Emacs entirely There is an escape character c c that Emacs intercepts so commands like c c c j and c c C k are not sent to the sub program So if you want to send c c to the sub program you must type C c C c If you want the most faithful terminal experience in Emacs ANSI term is your best bet I find the hassle of switching be tween line and character mode rather cumbersome so I pre fer to use shell mode instead M x eshell Emacs s Shell It shouldn t come as much of a surprise that someone has written an entire shell in elisp When you run m x eshell you are using a shell that is written in elisp that communicates The Practicals of Emacs through Emacs with the underlying host operating system and provides an excellent facsimile to a typical Linux style bash shell complete with elisp emulated cnu coreutils com mands like 1s cp cd and many more In practice that means you get a consistent shell across all platforms on which Emac
208. to day edit ing is writing or deleting text punctuated by specialist com mands Nevertheless in Emacs even mundane things like deleting text or using the kill ring the clipboard are highly optimized I think it s more important that you master movement first as that means you learn how to switch buffers and use Emacs s windowing system effectively That is why I have not talked about editing text at all until now two thirds of the way through the book Once you re comfortable open ing and saving files and getting around in Emacs without 166 The Theory of Editing losing track of what you were doing then you re ready to tackle more advanced editing concepts If you are reading this chapter and are still using the naviga tion keys the arrow keys page up and down and so on then that is fine too You will find the experience a bit dis jointed as a lot of what makes Emacs s movement keys so ef fective is the near harmonious relationship they have with their text editing counterparts This chapter will cover how to edit text that includes tradi tional staples like search and replace how to use the kill ring or clipboard how to use text macros and how to use text transformation tools Killing and Yanking Text Where other text editors merely cut text in Emacs you kill it The terminology as I talked about in Killing Yanking and CUA is bizarre and predates most graphical user interfaces entir
209. tracks to move their right hand away from the home row and move the point around by character At some point you will realize how jarring and how much it affects your speed it is and switch to Emacs s own commands Moving by Line The lt home gt and lt end gt keys move your point to the beginning and end of a line respectively and the Emacs equivalents are c a and c e Key Binding Purpose C a Moves point to the beginning of the line C e Moves point to the end of the line M m Moves point to the first non whitespace character on this line Both c a and c e behave exactly the same as lt home gt and lt end gt indeed both sets of keys are bound to the same command The Theory of Movement but I cover the definition of a line in the next chapter The last command m m is pure gold dust When you type M m the point will move to the beginning of the line and move forward until it encounters a non whitespace charac ter ergo if you re on an indented line of code and you want to change the identifier bar def foo self bar 42 After you type M m def foo self bar 42 If you re on a line without indentation the command will simply go to the beginning of the line Screen Logical and Visual Lines Emacs will by default wrap long lines to the right edge of the window but that raises an important question where does a line begin and end when it wraps The answer unfortunately requires a bit
210. uld be isp is fun and this is a great way to learn and use a powerful language in a practical environment Don t let the parentheses scare you they are actually its greatest strength Emacs as an Operating System When you run Emacs you are in fact launching a tiny C core responsible for the low level interactions with your op erating system s ABI That includes mundane things like file system and network access drawing things to the screen or printing control codes to the terminal The cornerstone of Emacs though is the elisp interpreter without it there is no Emacs The interpreter is creaky and old it s struggling Modern Emacs users expect a lot from their humble interpreter speed and asynchrony are the two main issues The interpreter runs ina single thread and inten sive tasks will lock the u1 thread But there are workarounds the issues manifold though they are do not deter people from writing ever more sophisticated packages When you write elisp you are not just writing snippets of code run in a sandbox isolated from everything you are altering a living system an operating system running on an operating system Every variable you alter and every func 3https www gnu org software emacs manual eintr html The Way of Emacs tion you call is carried out by the very same interpreter you use when you edit text Emacs is a hacker s dream because it is one giant mutable state Its simplicity i
211. unter persists between macro playbacks The Theory of Editing The command c x C k C c explicitly sets the counter as op posed to merely adding to it like with c x c k c a Finally C x C k C f is perhaps the most advanced of the counter com mands It takes a format string and formats the counter accord ing to this string type c h f format for more information on format strings So for instance you can decimalize the num ber or print it with leading or trailing zeros or anything similar like inserting a plain number and text Make sure you do not wrap the text you pass to C x C k C c in quotes as they are automatically escaped The standout command is c x C k q When you call it Emacs will tag that step in the macro recording and ask the user for advice in effect stopping the macro temporarily to prompt the user before continuing Query Key Binding Description Y Continues as normal N Skips the rest of the macro RET Stops the macro entirely Cr Recenters the screen C r Enters recursive edit C M c Exits recursive edit Y and N continue or stop the current iteration of the macro So if you are executing more than one macro in a row N would skip the rest and restart at the beginning of the macro Y merely continues on as normal RET stops the macro entirely and halts further macro playback You can recenter the screen which is not the same as the The Theory of Editing usual c 1 command and Emacs wi
212. use it a lot particularly if you have specific dictio nary requirements other than the default one used by customizing the group ispell Quoted Insert If you ever find yourself in need of inserting a literal TAB RET or Ascii control code character then you need quoted insert bound to c q Line feed vs carriage return If you want to insert a literal newline symbol type C q C j as that is the newline LINE FEED symbol and not your return key which is a CARRIAGE RETURN Quoted insert is clever enough to highlight ascu control codes using the face escape glyph so you can spot them visu ally Quoted insert does a literal insert of any character you feed it for example c q ESC inserts the asc control code also known as ESCAPE 4Which as you may recall you can customize with M x customize face Chapter 6 The Practicals of Emacs Emacs outshines all other editing soft ware in approximately the same way that the noonday sun does the stars It is not just bigger and brighter it simply makes everything else vanish Neal Stephenson In the Beginning was the Command Line In earlier chapters I have almost exclusively talked about the theoretical aspects of Emacs Galvanizing your brain and finding practical or novel applications is something else though for most theory is not enough In this final chapter I will show you what I call workflow walkthroughs that cover a spec
213. useful for more than just text For instance you can fill comments or doc strings too so they fit in under 80 char acters Key Binding Purpose M q Refills the paragraph point is in C x f Sets the fill column width C x Sets the fill prefix M x auto fill mode Toggles auto filling I use paragraph filling using M q often as I write comments in code and it is common for major modes to set a fill width c x f with the best practices used for that programming language or file type Consider this quote by Sherlock Holmes in A Scandal in Bo hemia that overruns the page The Theory of Editing It is an old maxim of mine that when you have excluded the After placing the point in the paragraph and typing m q It is an old maxim of mine that when you have excluded the impossible whatever remains however improbable must be the truth If you type m q with the prefix c u Emacs will attempt to justify the text also It is an old maxim of mine that when you have excluded the impossible whatever remains however improbable must be the truth Typing c x f will prompt you for a fill width As an example for the quotes above I put the point on the column I wanted the paragraph broken and pressed c x f approximately 42 characters The fill width is the number of characters per line but Emacs will not hyphenate words so don t make the fill width too small or it won t fill properly The fill prefix is a
214. useful if your team or personal preference dictates one comment style over another To see a list of comment styles available you must interrogate the variable comment styles by reading its description in Customize or by using m x describe variable also bound to c h v Search and Replace When you search for text you can do so either with regu lar expressions see the next section Regular Expressions or without Replacing text in Emacs is no different but with the added benefit of letting you leverage the power of elisp in the replace portion of search and replace In that sense Emacs is different from other editors you can use elisp and regexp capturing groups together powerful if you know elisp Emacs s regular expression implementa tion is also different from pcre as I will explain later It follows the cnu standard for regular expressions with many additions and quite a few omissions to make it suitable for both package developers and Emacs users Emacs s search and replace commands are Key Binding Purpose C M Query regexp search and replace 2PcRE stands for Perl Compatible Regular Expressions a style of regexp invented by the Perl programming language The Theory of Editing Key Binding Purpose M Query search and replace M x replace string Search and replace M x replace regexp Regexp search and replace You can also access Emacs s search and replace from inside Isearc
215. ver almost all of the blogs above and many more are found on the excellent Planet Emacs aggre gator http planet emacsen org Emacs And then there s Emacs It is and always will be the authoritative source of information for your Emacs
216. ving out of strings In newer versions of Emacs you can use C M u inside a string to jump to the opening quote On their own the commands do little more than jump in and out of list expressions but realize that combining this behavior with another command kill sexp will kill the sI will talk about killing text later on in the editing chapter The Theory of Movement balanced expression in front of the point so typing C M u and c M k for kill sexp will move up and kill the balanced expression you were just in Before B 2 10 10 3 After going up one level with C M u ic 5 2 10 10 3 After killing the s expression with C M k J lt 10 10 I use this functionality all the time it s one of Emacs s hid den gems that will make you very productive even if you don t program in usp For instance languages like Python use parentheses all over the place for dictionaries for tuples and for lists Combine the list commands with c m k and you can refactor large swathes of code easily and maintain your tempo because most commands that work on balanced ex pressions are bound to the c m modifier Because c mM d jumps into the next list expression follow ing point regardless of where it is in the buffer it s a powerful tool for moving around as well Like everything in Emacs realizing the potential of a command and commit ting it to working memory so you use
217. will do the same but for variables Elisp does not have namespaces so package authors pre fix their commands with the name of the package As the package name is Helm it makes sense to use apro pos to find commands beginning with helm or more precisely as the regular expression helm Coincidentally Helm has its own apropos completion engine M x helm apropos It will complete commands and variables amp functions make sure you only look in the Commands header as Functions are internal elisp functions not meant for general use Describe the prefix key I mentioned earlier that Helm has its own prefix key c x c In The Describe System you can tell Emacs to list all key bindings in a prefix key by finishing a prefix key with c h C x c C h The two methods yield slightly different answers because you are in fact asking two different questions so you should do both And finally The Theory of Movement e M x apropos command C h a is not limited to commands bound to a prefix key and it will happily show you commands that are unbound or even completely unrelated if your search pattern is too generic but this is still a great way of discovering hid den commands bound or not e Describing a prefix key with c h will only show you the commands bound to that prefix key Occasionally you will discover commands that although bound to that prefix key have nothing to do with the other commands Helm B
218. without you having to do any The Theory of Editing thing The commands below let you save and recall from the macro ring edit and bind macros to keys and more Key Binding Description C x C k C n Cycles macro ring to next x C k C p Cycles macro ring to previous C x C k n Names the last macro x C k b Binds the last macro to a key x C k e Edits last macro C x C k 1 Edits the last 300 keystrokes M x insert kbd macro Inserts macro as elisp Both c x C k C n and C x C k C p cycle the macro ring Emacs will helpfully display a portion of the macro when you do so you know which one is active You can name the macro with c x C k n which is useful if you want to save the macro to a file as you can then open your init file and call m x insert kbd macro to save it You can also temporarily for the current session only bind it to a key with c x C k b Lossage Emacs remembers the last 300 characters and commands called lossage you typed You can see this list of characters by typing c h 1 You can even save every keystroke you make in Emacs including sensitive things like passwords so beware by typing M x open dribble file I have absolutely no idea why it is named dribble file The Theory of Editing Macro editing is useful if you made mistakes The c x C k e command prints a list of macro commands that you edit as though it were text and when you finish type c c C c to commit the changes A similar comm
219. wledge Emacs s help system is roughly divided into three parts and knowing which one you need and when will save you time First Steps The Info Manual Emacs s own manuals and indeed all manuals in the enu ecosystem are written in TeXinfo If you have ever used the command line tool info you will have interacted with the TeXinfo hypertext viewer Emacs obviously has its own info viewer Emacs s info manual contains more than just topics relating to Emacs By default the info browser will index all the other info manuals installed on your system things like the cenu coreutils manuals will also be present A lot of people dislike info and I m not sure why It works in much the same way as a web browser though the key bind ings do differ To access Emacs s info reader type M x info or press C h i info the documentation browser will appear and you are free to use your mouse to click on the hyperlinks or use this table of keyboard shortcuts to navigate Key Purpose and Previous next node landr Go back forward in history nandp Previous next sibling node u Goes up one level to a parent node SPC Scroll one screen at a time TAB Cycles through cross references and links RET Opens the active link m Prompts for a menu item name and opens it q Closes the info browser Because info manuals have hierarchies in much the same First Steps way this and most other books do you ll want to use and
220. wn gt cycle through the com mand history in much the same way that using the up and down arrow keys would in normal terminal emulators In Emacs they literally move the point around in the buffer though this always confuses people not used to shell mode M r is triggers the history reverse Isearch It s a very power ful command that is worth learning c d deletes a character ahead of the point as it would anywhere else However if there is no input meaning you haven t typed anything at a prompt Emacs will send the control code EoF to terminate the running program Similarly c c C z does the same as C z in bash does for job control One nifty feature of shell mode is the ability to save the out put of the last command to a file with c c C s and to send it straight to your kill ring with c c c o TAB deserves its own special mention Shells like bash feature their own complex completion mechanisms and not just for files and paths Emacs does too You can complete things like hostnames for commands like ssh or groups and owners for chown M x ansi term Terminal Emulator Emacs has its own anst capable terminal emulator Invoking M x ansi term and selecting a shell you can run interactive programs like top or even vim and emacs The Practicals of Emacs Its main downside is its slowness and some obscure terminal emulation features are not supported Keys Description c c C j Switches to line mode C c C k Switches
221. works on any platform and re quire no external tools In return it is not as powerful Also it uses Emacs s regular expression engine and not shell glob bing Shell Commands As the chapter on dired demonstrated there are powerful commands in Emacs that interact with the shell For all other The Practicals of Emacs buffers there are the far more general but equally powerful shell commands that work on generic buffers Keys Description M Calls shell command and prints output C u M As above but inserts into buffer M amp Like m but asynchronous C u M amp Like c u m but asynchronous M Pipes region to shell command C u M Likes m but replaces region You can invoke any shell command with m and Emacs will print its output in the echo area if the text is only a few lines long or a dedicated buffer called she11 Command output if you used M and Async Shell Command if you used M amp Call ing either command with a universal argument will instead insert the output into your current buffer at the point The m command is far more practical It takes the region as input and sends it to the standard input of a shell command of your choosing and returns the output in much the same way asM either in the echo area or a dedicated buffer Call ing the command with a universal argument the active re gion is replaced instead that makes c u m extremely useful for offhand calls to commands
222. y justify if negative 1 There is only one capturing group though for complex alignment operations you may well have more than one group Finally the spacing Emacs will use align default spacing which defaults to the tab stops Emacs uses internally It is usually safe to leave this to its default but you can enter a number of absolute spacing and Emacs will try to follow it Amount of spacing or column if negative 1 Next and this is the one you are likely to actually care about is whether Emacs should repeat the command throughout the line Answer yes if you want Emacs to columnate all the symbols Repeat throughout the line yes The output now looks like this The Theory of Editing Price Product Qty Sold 2 00 Cappuccino 289 2 30 Caramel Latte 109 3 50 Americano 530 4 00 Macchiato 20 Emacs s align commands are powerful and useful if you often deal with unformatted text or code The only downside is that you have to wade through the complex mode to repeat the alignment process more than once on a single line Other Editing Commands Zapping Characters Kill commands work well on structured text they act on syntactic units But sometimes you want to kill to an arbi trary character The zap command m z does just that When you invoke it you are asked for a single character ahead of the point Zap then kills up to and including the character you typed http www example c
223. y identical log entries Emacs s highlighters are especially useful here as they high light patterns in your buffer in different colors so you can tell them apart The Practicals of Emacs Keys Description M s h p Highlights a phrase m s hr Highlights a regular expression M s h Highlights symbol at the point M s hu Removes highlighting under the point Highlighters are incredibly useful and even if you don t commit the keys to memory just know that they are all named highlight and are thus easy to execute when you need them with m x Log files are rarely static files they are constantly changing or appended to You can enable a minor mode so Emacs re freshes a file if it changes on your file system On newer ver sions of Emacs it ll use file change events on Windows and Linux and polling on older systems that don t support noti fications Keys Description M x auto revert mode Reverts buffer when file changes M x auto revert tail mode Appends changes when file changes Both modes are similar M x auto revert mode is useful if the file content changes frequently Emacs detects changes and simply reloads the entire file m x auto revert tail mode on the other hand works the same way as tail f when the file changes the changes are appended to the end of the buffer and Emacs will scroll accordingly The Practicals of Emacs Browsing Other Files There is of course nothing stopping you from apply
224. y more That binary will spawn standalone instances only You must use the similarly named emacsclient instead Set your EDITOR environment variable to emacsclient and things should just work from then on First Steps The emacsclient binary has its own set of switches you should know about Switch Purpose help Displays the help c Creates a graphical frame if X is available or a terminal frame if X is unavailable nw Creates a terminal frame n The client will return immediately instead of waiting for you to save your changes Useful if you just want to open a bunch of files When you launch an emacsclient instance the client will wait for the file s to finish editing Pressing c x will switch to the next buffer you re editing through a client when you ve done this for the file s you opened Emacs will sig nal to the client to exit and return control to the terminal If you re using a tool like git that lets you use your EDITOR to edit commit messages when using other editors git will wait until it receives the go ahead from your editor that it has saved the commit messages to a temporary file before resuming with the commit operation You can add the n switch if you want the client to just open the files and not wait I find this useful if Pm doing exploratory work or if I want the files permanently open in Emacs First Steps The Emacs Interface emacs mickey vb A Ghd Welcome
225. you type C x b the name of the former buffer is the default action meaning pressing RET will take you to it Switching buffers is second nature to Emacs hackers Once you re comfortable with it you won t even think about you ll switch through buffers quickly and instantaneously without so much as a second thought Buffer naming conventions Some buffers in Emacs interact with external programs perhaps a shell like bash or they hold transient information generated by Emacs itself To distinguish them from user created buffers they have characters in their names like so buffername The fact that files and buffers are two distinct but related concepts makes sense when you consider the nature of scratch buffers buffers that you create and use but don t intend to permanently save For instance if you want to run a key board macro or do extensive text editing on a region of code an Emacs hacker would copy it to a made up scratch buffer created simply by switching to a buffer name that does not The Theory of Movement exist do the requisite editing and switch back to the origi nal buffer Writing buffers to files If you later decide you want to save the buffer to the file system you can press C x C s to save it Listing buffers One more useful command is c x c b It dis plays a list of all buffers running on your system Buffer Switching Alternatives The built in interface for buffer switching is
226. you use both are referred to as ispell in Emacs Spell checking on Windows You need to install the aspe11 or ispell on Win dows yourself for this functionality to work I use M frequently for offhand corrections When you use it Emacs will tell you if it thinks it is correct or not If Emacs thinks it is wrong it will list suggestions to choose from and Emacs will replace the original word Flyspell mode is useful and works identically to word pro cessors misspelled words are highlighted with squiggly lines and all However that mode is designed for text and not code for code use M x flyspell prog mode as it limits spell checking to just your comments strings and doc strings Again a very nifty feature Spell checking TeX If you write LaTeX or TeX often you should add this to your init file as it tells Emacs how to parse TeX add hook tex mode hook lambda setq ispell parser tex Unfortunately there is no Customize equivalent 3ASpell can be found here http aspell net win32 The Theory of Editing If you enable either Flyspell minor mode it also enables a secondary command bound to c m i and c that auto cor rects the word at point It picks the first likely match and cor rects the word at the point subsequent calls cycle through the words much quicker than m as it insists on asking you which correction you want Customize I recommend you customize this feature if you
227. you yank from the kill ring if you want to paste It s fine to refer to it as paste in daily conversation but you should probably learn the real Emacs terminology to make it easier to find things in Emacs itself The two yank commands you want to know about are Key Binding Purpose Clipboard C y Yank last kill paste M y Cycle through kill ring replacing yanked text Yanking works as you would expect it inserts the current entry in the kill ring to the point in your active buffer Re peat calls to yank will insert the same text As I mentioned before the kill ring is a ring like the undo The Theory of Editing ring and it remembers former kills so you can cycle through them Cycling through the kill ring is easy 1 Press c y where you want the yanked text to appear 2 Without executing another command this includes moving around and editing text type M y to step back through Emacs s kill ring Transposing Text Transposing text is the act of swapping two syntactic units of text with one another At first glance you may think they are of limited utility but actually they are useful and if you spend the effort and master them you will not regret it When you edit text you often mistakenly swap words in prose or for instance arguments to a function in code Dedicated commands that swap things around are therefore very useful When you transpose text you do so using syntactic units in much the s
228. your changes until you save After that you have to manually go through and undo or use the Revert button s Erase Customizations op tion All Customizations are stored in your init file by default or possibly a separate custom file and like the rest of Emacs the changes are stored as elisp code making it possible for you to go back and manually change the elisp Instead of navigating through the tree of groups you can use one of several shortcut commands M x customize displays the Customize interface and all the groups customize browse Opens a tree group browser Much like the regular Customize interface but without the group descriptions customize customized customizes options and faces that you have changed but not saved Useful if you want to tweak things customize changed displays all options changed since a particular Emacs version Good way to discover new features and options customize face prompts for the name of a face to Customize I recommend you put your point on the face you want to change It ll fill in the name automatically customize group prompts for a group name e g python to Customize First Steps M x customize mode customizes the major mode of your cur rent buffer You should do this for every major mode you use It s a quick way to change things and gain an overview of what your major mode can do M x customize saved Displays all your saved options and faces Extremely ha

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