Introduction to Emacs

Emacs is an extensible, customizable, self-documenting real-time display editor. It was first designed for UNIX, but for Win* and Mac as well (see the above front page for Emacs).
Since it is "programmable" (in a version of Lisp), it is being continuously extended to provide support for editing different types of files (HTML, TeX, C++, shell-scripting, Perl, etc.). It can also handle mail, news, spell-checking, etc. It provides interfaces for many UNIX commands as well (to mention only one: a convenient way to compare two files, based on diff). Most of these add-ons come as separate packages (which are plain-text files), that are loaded when needed.

GNU Emacs is "free software"; this means that everyone is free to use it and free to redistribute it on certain conditions (for details, check the help menu within Emacs).

To invoke it, type emacs & in a shell.
If you do not want Emacs to run in a separate window, type instead emacs -nw ("nw" stands for "no window"). In this case you will have no mouse support (but can still use the menus; see below), and might have a problem with CONTROL-s (see the "Note" in the part about "Searching").

Originally Emacs actions (e.g., save file) were accessible through various key combinations. By now, you can do quite a bit using only the mouse. However, using a key combination is quicker than "aiming and clicking" the mouse.
NOTE: if, e.g., you are invoking Emacs on a remote machine, the mouse might not be usable. You can reach the menus by the sequence M-` (note that ` is the less frequently used quotation mark, the opposite of '). See below what M- means.

Emacs comes with an incorporated help (see some of its items on the starting screen) and manual.
To reach the help, type CONTROL-h and follow the instructions (in the bottom line of the screen).
To read the manual (as well as the manual of other applications), type C-h i. Or, use the mouse to open the "Help" menu. Then follow the instructions at the top of the page.
The help includes a tutorial. You can reach it directly by typing C-h t.

NOTE: In Emacs parlance, e.g., C-x means CONTROL-x, while M-x means META-x; you have to press and hold the CONTROL or META key, and then press x.
The META key is sometimes labelled ALT. If you do not have it, press ESCAPE instead, followed by, say, x.

In any Emacs buffer (e.g., in the manual or tutorial), you can search forward with C-s and backward with C-r. Watch both the dialog box (at the bottom of the screen) and the buffer in which you started the search!
To reach the next occurrence or change direction, repeat C-s or C-r. To cancel the search press C-g. To stop at a hit, press RETURN. To search again for the same sequence, type C-s or C-r twice.

JUST IN CASE:

  • If you want to cancel an Emacs command (either because you typed the wrong thing, or it takes too long) type C-g.
  • Sometimes you will get into what is called a "recursive editing level". This is indicated by square brackets in the mode line, surrounding the parentheses around the major mode name. For example, you might see [(Fundamental)] instead of (Fundamental).
    To get out of the recursive editing level, type ESC ESC ESC. That is an all-purpose "get out" command. You can also use it for eliminating extra windows, and getting out of the minibuffer (i.e., the dialog box).
    You cannot use C-g to get out of a recursive editing level. This is because C-g is used for canceling commands and arguments WITHIN the recursive editing level.
  • Emacs lets you undo essentially everything! Check the command listed under the "Edit" menu. Often it is one (or both) of C-_ and C-/.
  • You can exit Emacs by typing C-x C-c, or looking into the "File" menu. If there are unsaved buffers, you will be asked to take care of them.

    This is the part of the tutorial that explains searching, and lets you practice as well (however, for that you should be reading it in Emacs - do C-h t and advance quite a few pages). 

    * SEARCHING
-----------

Emacs can do searches for strings (these are groups of contiguous
characters or words) either forward through the text or backward
through it.  Searching for a string is a cursor motion command;
it moves the cursor to the next place where that string appears.

The Emacs search command is different from the search commands
of most editors, in that it is "incremental".  This means that the
search happens while you type in the string 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 try 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.  <Return> 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.
   Now you have searched for "cursor", once.
>> Type C-s again, to search for the next occurrence of "cursor".
>> Now type <Delete> four times and see how the cursor moves.
>> Type <Return> 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 the search is currently
"failing".  C-g would also terminate the search.

NOTE: On some systems, typing C-s will freeze the
screen and you will see no further output from Emacs. This indicates that
an operating system "feature" called "flow control" is
intercepting the C-s and not letting it get through to Emacs. To unfreeze
the screen, type C-q. Then see the section "Spontaneous Entry to
Incremental Search" in the Emacs manual for advice on dealing with
this "feature".

If you are in the middle of an incremental search and type <Delete>,
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 have typed "c", to search for the first
occurrence of "c".  Now if you type "u", the cursor will move
to the first occurrence of "cu".  Now type <Delete>.  This erases
the "u" from the search string, and the cursor moves back to
the first occurrence of "c".

If you are in the middle of a search and type a control or meta
character (with a few exceptions--characters that are special in
a search, such as C-s and C-r), the search is terminated.

The C-s starts a search that looks for any occurrence of the search
string AFTER the current cursor position.  If you want to search for
something earlier in the text, type C-r instead.  Everything that we
have said about C-s also applies to C-r, except that the direction of
the search is reversed.