TeachEmacs

You are looking at the EMACS tutorial. Comments on this document should be mailed to BUG-EMACS.

EMACS commands generally involve the CONTROL key (sometimes labelled CTRL or CTL) or the META key (sometimes labelled EDIT). Rather than write out META or CONTROL each time we want you to prefix a character, we'll use the following abbreviations:

C-<chr> means hold the CONTROL key while typing the character <chr> Thus, C-F would be: hold the CONTROL key and type F. M-<chr> means hold the META or EDIT key down while typing <chr>. If there is no META or EDIT key, type <ALT>, release it, then type the character <chr>. "<ALT>" stands for the key labelled "ALT" or "ESC".

Important note: if you must exit at some point, type C-X C-Z. The characters ">>" at the left margin indicate directions for you to try using a command. For instance:

>> Now type C-V (View next screen) to move to the next screen. (go ahead, do it by depressing the control key and V together). From now on, you'll be expected to do this whenever you finish reading the screen.

Note that there is an overlap when going from screen to screen; this provides some continuity when moving through the file.

The first thing that you need to know is how to move around from place to place in the file. You already know how to move forward a screen, with C-V. To move backwards a screen, type M-V (depress the META key and type V, or type <ALT>V if you don't have a META or EDIT key).

>> Try typing M-V and then C-V to move back and forth a few times.

SUMMARY -------

The following commands are useful for viewing screenfuls:

C-V Move forward one screenful M-V Move backward one screenful C-L Clear screen and redisplay everything putting the text near the cursor at the center.

>> Find the cursor and remember what text is near it. Then type a C-L. Find the cursor again and see what text is near it now.

BASIC CURSOR CONTROL --------------------

Getting from screenful to screenful is useful, but how do you reposition yourself within a given screen to a specific place? There are several ways you can do this. One way (not the best, but the most basic) is to use the commands previous, backward, forward and next. As you can imagine these commands (which are given to EMACS as C-P, C-B, C-F, and C-N respectively) move the cursor from where it currently is to a new place in the given direction. Here, in a more graphical form are the commands:

Previous line, C-P : : Backward, C-B .... Current cursor position .... Forward, C-F : : Next line, C-N

You'll probably find it easy to think of these by letter. P for previous, N for next, B for backward and F for forward. These are the basic cursor positioning commands and you'll be using them ALL the time so it would be of great benefit if you learn them now.

>> Do a few C-N's to bring the cursor down to this line.

>> Move into the line with C-F's and then up with C-P's. See what C-P does when the cursor is in the middle of the line.

Lines are separated by a pair of characters, a Return and a Linefeed, but EMACS almost always makes them look like one character. You can think of it as a Newline.

>> Try to C-B at the beginning of a line. Do a few more C-B's. Then do C-F's back to the end of the line and beyond.

When you go off the top or bottom of the screen, the text beyond the edge is shifted onto the screen so that your instructions can be carried out while keeping the cursor on the screen.

>> Try to move the cursor off the bottom of the screen with C-N and see what happens.

If moving by characters is too slow, you can move by words. M-F (Meta-F) moves forward a word and M-B moves back a word.

>> Type a few M-F's and M-B's. Intersperse them with C-F's and C-B's.

Notice the parallel between C-F and C-B on the one hand, and M-F and M-B on the other hand. Very often Meta characters are used for operations related to English text whereas Control characters operate on the basic textual units that are independent of what you are editing (characters, lines, etc). There is a similar parallel between lines and sentences: C-A and C-E move to the beginning or end of a line, and M-A and M-E move to the beginning or end of a sentence.

>> Try a couple of C-A's, and then a couple of C-E's. Try a couple of M-A's, and then a couple of M-E's.

See how repeated C-A's do nothing, but repeated M-A's keep moving farther. Do you think that this is right?

Two other simple cursor motion commands are M-< (Meta Less-than), which moves to the beginning of the file, and M-> (Meta Greater-than), which moves to the end of the file. You probably don't need to try them, since finding this spot again will be boring. If you need the shift key to type a "<", then you must also use the shift key to type M-<. Otherwise, you would be typing M-, .

The location of the cursor in the text is also called "point". To paraphrase, the cursor shows on the screen where point is located in the text.

Here is a summary of simple moving operations including the word and sentence moving commands:

C-F Move forward a character C-B Move backward a character

M-F Move forward a word M-B Move backward a word

C-N Move to next line C-P Move to previous line

C-A Move to beginning of line C-E Move to end of line

M-A Move back to beginning of sentence M-E Move forward to end of sentence

M-< Go to beginning of file M-> Go to end of file

>> Try all of these commands now a few times for practice. Since the last two will take you away from this screen, you can come back here with M-V's and C-V's. These are the most often used commands.

Like all other commands in EMACS, these commands can be given arguments which cause them to be executed repeatedly. The way you give a command a repeat count is by typing C-U and then the digits before you type the command. If you have a META or EDIT key, you can omit the C-U if you hold down the META or EDIT key while you type the digits. This is easier, but we recommend the C-U method because it works on any terminal.

For instance, C-U 8 C-F moves forward eight characters.

>> Try giving a suitable argument to C-N or C-P to come as close as you can to this line in one jump.

The only apparent exception to this is the screen moving commands, C-V and M-V. When given an argument, they scroll the screen up or down by that many lines, rather than screenfuls. This proves to be much more useful.

>> Try typing C-U 8 C-V now.

Did it scroll the screen up by 8 lines? If you would like to scroll it down you can give an argument to M-V.

WHEN EMACS IS HUNG -----------------

If EMACS gets into an infinite (or simply very long) computation which you don't want to finish, you can stop it safely by typing C-G. You can also use C-G to discard a numeric argument or the beginning of a command that you don't want to finish.

>> Type C-U 100 to make a numeric arg of 100, then type C-G. Now type C-F. How many characters does it move? If you have typed an <ALT> by mistake, you can get rid of it with a C-G.

If you type <ALT> <ALT>, you get into something known as a "minibuffer". That is an advanced feature of EMACS. We mention it now only to say that you can get out of it with one or two C-G's if you get into it by accident.

INSERTING AND DELETING ----------------------

If you want to type text, just do it. Characters which you can see, such as A, 7, *, etc. are taken by EMACS as text and inserted immediately. Type <Return> (the carriage-return key) to insert a line separator.

You can delete the last character you typed by typing <Rubout>. <Rubout> is a key on the keyboard, which might be labelled "Delete" instead of "Rubout" on some terminals. More generally, <Rubout> deletes the character immediately before the current cursor position.

>> Do this now, type a few characters and then delete them by typing <Rubout> a few times. Don't worry about this file being changed; you won't affect the master tutorial. This is just a copy of it.

>> Now start typing text until you reach the right margin, and keep typing. When a line of text gets too big for one line on the screen, the line of text is "continued" onto a second screen line. The exclamation mark at the right margin indicates a line which has been continued. >> Use <Rubout>s to delete the text until the line fits on one screen line again. The continuation line goes away.

>> Move the cursor to the beginning of a line and type <Rubout>. This deletes the line separator before the line and merges the line onto the previous line. The resulting line may be too long to fit, in which case it has a continuation line. >> Type <Return> to insert the separator again.

Remember that most EMACS commands can be given a repeat count; Note that this includes characters which insert themselves.

>> Try that now -- type C-U 8 * and see what happens.

You've now learned the most basic way of typing something in EMACS and correcting errors. You can delete by words or lines as well. Here is a summary of the delete operations:

<Rubout> delete the character just before the cursor C-D delete the next character after the cursor

M-<Rubout> kill the word immediately before the cursor M-D kill the next word after the cursor

C-K kill from the cursor position to end of line M-K kill to the end of the current sentence

Notice that <Rubout> and C-D vs M-<Rubout> and M-D extend the parallel started by C-F and M-F (well, <Rubout> isn't really a control character, but let's not worry about that). C-K and M-K are like C-E and M-E, sort of, in that lines are opposite sentences.

Now suppose you kill something, and then you decide that you want to get it back? Well, whenever you kill something bigger than a character, EMACS saves it for you. To yank it back, use C-Y. Note that you don't have to be in the same place to do C-Y; This is a good way to move text around. Also note that the difference between "Killing" and "Deleting" something is that "Killed" things can be yanked back, and "Deleted" things cannot. Generally, the commands that can destroy a lot of text save it, while the ones that attack only one character, or nothing but blank lines and spaces, do not save.

For instance, type C-N a couple times to position the cursor at some line on this screen.

>> Do this now, move the cursor and kill that line with C-K.

Note that a single C-K kills the contents of the line, and a second C-K kills the line itself, and make all the other lines move up. If you give C-K a repeat count, it kills that many lines AND their contents.

The text that has just disappeared is saved so that you can retrieve it. To retrieve the last killed text and put it where the cursor currently is, type C-Y.

>> Try it; type C-Y to yank the text back.

Think of C-Y as if you were yanking something back that someone took away from you. Notice that if you do several C-K's in a row the text that is killed is all saved together so that one C-Y will yank all of the lines.

>> Do this now, type C-K several times.

Now to retrieve that killed text:

>> Type C-Y. Then move the cursor down a few lines and type C-Y again. You now see how to copy some text.

What do you do if you have some text you want to yank back, and then you kill something else? C-Y would yank the more recent kill. But the previous text is not lost. You can get back to it using the M-Y command. After you have done C-Y to get the most recent kill, typing M-Y replaces that yanked text with the previous kill. Typing M-Y again and again brings in earlier and earlier kills. When you have reached the text you are looking for, you can just go away and leave it there. If you M-Y enough times, you come back to the starting point (the most recent kill).

>> Kill a line, move around, kill another line. Then do C-Y to get back the second killed line. Then do M-Y and it will be replaced by the first killed line. Do more M-Y's and see what you get. Keep doing them until the second kill line comes back, and then a few more. If you like, you can try giving M-Y positive and negative arguments.

FILES -----

In order to make the text you edit permanent, you must put it in a file. Otherwise, it will go away when your invocation of EMACS goes away. You put your editing in a file by "visiting" the file. What visiting means is that you see the contents of the file in your EMACS; and, loosely speaking, what you are editing is the file itself. However, the changes still don't become permanent until you "save" the file. This is so you can have control to avoid leaving a half-changed file around when you don't want to. Even then, EMACS really makes a new version of the file and doesn't change the old version at all (so that you can verify or throw away your changes later if you like).

If you look near the bottom of the screen you will see a line that starts with "EMACS (Fundamental) Main:" and continues with the filename DSK:<your directory>TEACH-EMACS.TUTORIAL. This is the name of your own temporary copy of the text of the EMACS tutorial; the file you are now visiting. Whatever file you visit, that file's name will appear in that precise spot.

The commands for visiting and saving files are unlike the other commands you have learned in that they consist of two characters. They both start with the character Control-X. There is a whole series of commands that start with Control-X; many of them have to do with files, buffers, and related things, and all of them consist of Control-X followed by some other character.

Another thing about the command for visiting a file is that you have to say what file name you want. We say the command "reads an argument from the terminal" (in this case, the argument is the name of the file). After you type the command

C-X C-V Visit a file

EMACS will ask you for the file name. You should end the name with the Return key. After this command, you will see the contents of the file in your EMACS. You can edit the contents. When you wish to make the changes permanent, issue the command

C-X C-S Save the file

A new version of the file will be created. When the operation is finished, EMACS prints the name and version saved. You should save fairly often, so that you will not lose very much work if the system should crash.

If you forget to save before visiting a different file, EMACS will remind you that you made changes and ask you whether to save them. (If you don't save them, they will be thrown away. That might be what you want!) You should answer with a "Y" to save them or a "N" to throw the changes away.

To make a new file, just visit it "as if" it already existed. Then start typing in the text. When you ask to "save" the file, EMACS will really create the file with the text that you have inserted. From then on, you can consider yourself to be editing an already existing file.

It is not easy for you to try out visiting a file and continue with the tutorial. But you can always come back into the tutorial by starting it over and skipping forward. So, when you feel ready, you should try visiting a file named "FOO", putting some text in it, and saving it; then exit from EMACS and look at the file to be sure that it worked.

EXTENDING THE COMMAND SET -------------------------

There are many, many more EMACS commands than could possibly be put on all the control and meta characters. EMACS gets around this with the X (eXtend) command. This comes in two flavors:

C-X Character eXtend. Followed by one character. M-X Named command eXtend. Followed by a long name.

These are commands that are generally useful but used less than the commands you have already learned about. You have already seen two of them: the file commands C-X C-V to Visit and C-X C-S to Save. Another example is the command to tell EMACS that you'd like to stop editing. The command to do this is C-X C-Z. Think of it as Z for zapping yourself.

There are many C-X commands. The ones you need immediately are:

C-X C-V Visit file. C-X C-S Save file. C-X C-Z Quit EMACS. This does NOT save your file. The standard way to save and exit is C-X C-S C-X C-Z.

Named eXtended commands are commands which are used even less frequently, or commands which are used only in certain modes. These commands are usually called "functions". An example is the function Replace String, which globally replaces one string with another. When you type M-X, EMACS prompts you at the bottom of the screen with M-X and you should type the name of the function you wish to call; in this case, "Replace String". Just type "REP<Alt>" and EMACS will complete the name. Then you type the string that you want to replace, an <Alt>, the string you want to replace it with, and a return. When the <Alt> is echoed, it looks like this: $

>> Move the cursor to the blank line two lines below this one. Then type M-X rep<Alt>changed<Alt>altered<Return>.

Notice how this line has changed: you've replaced the word c-h-a-n-g-e-d with "altered" wherever it occurs after the cursor.

MODE LINE ---------

If EMACS sees that you are typing commands slowly it shows them to you at the bottom of the screen in an area called the echo area. The echo area contains the bottom three lines of the screen. The line immediately above them is called the MODE LINE. The mode line says something like

EMACS (Fundamental) Main: filename --nn%-- *

This is a very useful "information" line.

You already know what the filename means -- it is the file you have visited. What the --nn%-- means is that nn percent of the file is above the top of the screen. If the top of the file is on the screen, it will say --TOP-- instead of --00%--. If the bottom of the file is on the screen, it will say --BOT--. If you are looking at a file so small it all fits on the screen, the --nn%-- will simply not be there.

The star means that you have made changes to the text. Right after you visit or save a file, there is no star.

The part of the mode line inside the parentheses is to tell you what modes you are in. The default mode is Fundamental which is what you are in now. It is an example of a "major mode". There are several major modes in EMACS for editing different languages and text, such as LISP mode, Text mode, etc. At any time one and only one major mode is active, and its name can always be found in the mode line just where "Fundamental" is now. Each major mode makes a few commands behave differently. For example, there are commands for creating comments in a program, and since each programming language has a different idea of what a comment should look like, each major mode has to insert comments differently. Each major mode is the name of an extended command, which is how you get into the mode. For example, M-X Fundamental Mode is how to get into Fundamental mode.

If you are going to be editing English text, such as this file, you should probably use Text Mode. >> Type M-X Text Mode<Return>.

Don't worry, none of the commands you have learned changes EMACS in any great way. But you can now observe that periods are no longer part of words when you do M-F or M-B! Major modes are usually like that: commands don't change into completely unrelated things, but they work a little bit differently.

Major modes are called major because there are also minor modes. They are called minor because they aren't alternatives to the major modes, just minor modifications of them. Each minor mode can be turned on or off by itself, regardless of what major mode you are in, and regardless of the other minor modes. So you can use no minor modes, or one minor mode, or any combination of several minor modes.

One minor mode which is very useful, especially for editing English text, is Auto Fill mode. When this mode is on, EMACS breaks the line in between words automatically whenever the line gets too long. You can turn this mode on by doing M-X Auto Fill Mode<Return>. When the mode is on, you can turn it off by doing M-X Auto Fill Mode<Return>. If the mode is off, this function turns it on, and if the mode is on, this function turns it off. This is called "toggling".

>> Type M-X Auto Fill Mode<Return> now. Then insert a line of "asdf " over again until you see it divide into two lines. You must put in spaces between them because Auto Fill breaks lines only at spaces. Notice that "Fill" appears in the mode line in addition to the name of the major mode, not instead of it.

The margin is usually set at 70 characters, but you can change it with the C-X F command. You should give the margin setting you want as a numeric argument.

>> Type C-X F with an argument of 20. (C-U 2 0 C-X F). Then type in some text and see EMACS fill lines of 20 characters with it. Then set the margin back to 70 using C-X F again.

RECURSIVE EDITING LEVELS ------------------------

Sometimes you will get into what is called a "recursive editing level". This is a command which, as part of its job, wants you to edit some text. A good example is M-X Edit Options<Return>, which shows you a list of many variables called options, and their values. You can edit this list to change the values and thus turn the optional features they control on or off. When you are done, you can say "ok" with the command C-M-Z. If you do not have a META or EDIT key on your terminal, type C-Z C-Z or <Alt>C-Z. This is called "exiting" the recursive editing level. The text (the list of options) will disappear and the changes you have made will be digested.

>> Type M-X Edit Options<Return> and see the list of options. Find the option "Auto Fill Mode" and edit the value to be 1. Now exit with C-Z C-Z and see that "Fill" is now present in the mode line, and auto-filling is in effect. Do M-X Edit Options<Return> again and set the value of the option to 0, and exit. "Fill" will disappear from the mode line and auto-filling will no longer be in effect.

If you change your mind about the changes you have made inside the recursive editing level, you can "abort" instead of "exit" by typing the C-] command. When you abort, the changes you have made will NOT take effect.

>> Type M-X Edit Options<Return>. Set the value of Auto Fill Mode to 1 again, but instead of exiting, abort with C-]. Say "Y" when it asks you whether you mean it. You will see that "Fill" is not there in the mode line, because by aborting you said that your change to the value of the option should be ignored. Do M-X Edit options<Return> again. You will see that the value of Auto Fill Mode is still 0.

You can't use C-G to get out of a recursive editing level because C-G is used for discarding numeric arguments and partially typed commands WITHIN the recursive editing level.

SEARCHING ---------

EMACS can do searches for strings (these are groups of contiguous characters or words) either forward through the file or backward through it. To search for the string means that you are trying to locate it somewhere in the file and have EMACS show you where the occurrences of the string exist. This type of search is somewhat different from what you may be familiar with. It is a search that is performed as you type in the thing to search for. The command to initiate a search is C-S for forward search, and C-R for reverse search. BUT WAIT! Don't do them now. When you type C-S you'll notice that the string "I-search" appears as a prompt in the echo area. This tells you that EMACS is in what is called an incremental search waiting for you to type the thing that you want to search for. <ALT> terminates a search.

>> Now type C-S to start a search. SLOWLY, one letter at a time, type the word 'cursor', pausing after you type each character to notice what happens to the cursor. >> Type C-S to find the next occurrence of "cursor". >> Now type <Rubout> four times and see how the cursor moves. >> Type <Alt> to terminate the search.

Did you see what happened? EMACS, in an incremental search, tries to go to the occurrence of the string that you've typed out so far. To go to the next occurrence of 'cursor' just type C-S again. If no such occurrence exists EMACS beeps and tells you that it is a failing search. C-G would also terminate the search.

If you are in the middle of an incremental search and type <Rubout>, you'll notice that the last character in the search string is erased and the search backs up to the last place of the search. For instance, suppose you currently have typed 'cu' and you see that your cursor is at the first occurrence of 'cu'. If you now type <Rubout>, the 'u' on the search line is erased and you'll be repositioned in the text to the occurrence of 'c' where the search took you before you typed the 'u'. This provides a useful means for backing up while you are searching.

If you are in the middle of a search and happen to type a control character (other than a C-S or C-R, which tell EMACS to search for the next occurrence of the string), the search is terminated.

The C-S starts a search that looks for any occurrence of the search string AFTER the current cursor position. But what if you want to search for something earlier in the text? To do this, type C-R for Reverse search. Everything that applies to C-S applies to C-R except that the direction of the search is reversed.

GETTING MORE HELP -----------------

In this tutorial we have tried to supply just enough information to get you started using EMACS. There is so much available in EMACS that it would be impossible to explain it all here. However, you may want to learn more about EMACS since it has numerous desirable features that you don't know about yet. EMACS has a great deal of internal documentation. All of these commands can be accessed through the HELP character. If there is no key labelled "HELP" on your keyboard, you can type the <HELP> character as C-M-? (Control-Meta-Question Mark = C-Z ?), or with the <HOLD> key, on Datamedia terminals. Be warned: many terminals are faulty and do not allow you to type the character C-_ in the logical way (hold down Control and type an underscore). For example, on a VT-100 it works to hold down Control and type "/" or "?"; on a hazeltine you have to type Control-Shift-O !

To use the HELP features, type the <HELP> character, and then a character saying what kind of help you want. If you are REALLY lost, type <HELP> ? and EMACS will tell you what kinds of help it can give. If you have typed the <HELP> character and decide you don't want any help, just type C-G to abort.

The most basic HELP feature is <HELP> C. Type <HELP>, a C, and a command character, and EMACS prints a description of the command. When you are finished reading it, type a Space or a C-G (quit) to bring your text back on the screen.

>> Type <HELP> C Control-P. When you are finished reading the output, type a Space. The message should be something like

The command Control-P runs the function ^R Up Real Line: Move up vertically to the next real line. Continuation lines are skipped.

The "name of the function" is important for people who are customizing EMACS. It is what appears in the EMACS CHART as the documentation for the command character. It often starts with the characters "^R". For now you can ignore it.

Multi-character commands such as C-X C-Z and (if you have no META or EDIT key) <ALT>V are also allowed after <HELP> C.

Here are some other useful <HELP> options:

<HELP> D Describe a function. You type in the name of the function. To see your text again when it is done, type a Space or C-G.

>> Try typing <HELP> D Replace String<Return>. Then type a Space when you are finished reading it.

<HELP> A Apropos. Type in a keyword and EMACS will list all the functions containing that keyword. For some functions it will also list a one or two character command which has the same effect.

>> Type <HELP> A File<Return>. You will see a list of all functions (M-X commands) with "file" in their names. You will also see commands like C-X C-V and C-X C-S, listed under the corresponding function names. When it says "--More--" at the bottom of the screen, type a Space to see the rest of the list.

<HELP> I Run the INFO program. INFO contains the same information as in the EMACS manual, as well as documentation of some other system programs, organized by topic. Here is where you can find out about, for instance, special commands for editing LISP code, handling buffers, replacing text, filling and justifying text, etc.

INFO is a fairly sophisticated documentation finder which is what you will have to use to learn more about EMACS. After you are familiar with the material in this tutorial, you should try invoking INFO with <HELP> I and then, as soon as you are in INFO, type H. The H will get you INFO's tutorial, which will teach you how to use INFO just as this has taught you how to use EMACS.

CONCLUSION ----------

Remember, to exit use C-M-Z (C-Z C-Z). You will not be screwed if you exit with C-C but various features will not be provided, so it is probably wise to develop the habit of using C-M-Z.

This tutorial is meant to be understandable to all new users, so if you found something unclear, don't sit and blame yourself - complain!