Typically, ex commands are used to do perform complex actions such as global search & replace, or actions which require an argument such as writing the edit buffer out to a different file.
Ex is also used as the configuration language for elvis; configuration scripts such as elvis.ini, .exrc (or elvis.rc), and elvis.arf contain a series of ex commands.
You can switch freely between vi and ex. If you're in vi mode, you can enter a single ex command line via the visual : command, or more permanently switch via the visual Q command. If you're in ex mode, you can switch to vi mode via ex's :vi command.
Normally elvis will start in vi mode, but you can force it to start in ex mode by supplying a -e command line flag. On UNIX systems, you can link elvis to a name which ends with "x" to achieve the same effect.
The remainder of this section discusses how to enter lines, the general syntax of an ex command line, and the specific commands which elvis supports.
Any previously entered lines will still be in the "Elvis ex history" buffer, and you can use the arrow keys to move back and edit earlier commands. You can even use the Control-O input-mode command with the ?regexp visual command, to search for an earlier command line.
The Tab key has a special function when you're inputting text into the "Elvis ex history" buffer. It is used for file name expansion. The preceding word is assumed to be a partial file name, and elvis searches for all matching files. If there are multiple matches, then elvis fills in as many characters of the name as possible, and then beeps; or, if no additional characters are implied by the matching file names, then elvis lists all matching names and redisplays the command line. If there is a single match, then elvis completes the name and appends a tab character. If there are no matches, then elvis simply inserts a tab character.
You can bypass the file name expansion by typing a Control-V before the Tab key. You can also disable file name completion all together by setting the "Elvis ex history" buffer's inputtab option to "tab", via the following command:
:(Elvis ex history)set inputtab=tab
When you hit the Enter key on a line in the "Elvis ex history" buffer, elvis sends that line to the ex command parser, which is described in the next section.
A window ID is typed in as a decimal number followed by a colon character. If you don't supply a window ID (and you almost never will) then it defaults to the window where you typed in the command line. The :buffer command lists the buffers, and shows which one is being edited in which window. Also, the windowid option indicates the ID of the current window.
A buffer ID is given by typing an opening parenthesis, the name of the
buffer, and a closing parenthesis.
For user buffers, the name of the buffer is usually identical to the name of
the file that it corresponds to.
For example, a file named ~/.Xdefaults would be loaded into a buffer which
could be addressed as (~/.Xdefaults).
Elvis also assigns numbers to user buffers, which may be more convenient
to type since numbers are generally shorter than names.
If ~/.Xdefaults is the first file you've edited since starting elvis, then
its buffer could be addressed as (1).
The :buffer command shows the number for each user
buffer.
Elvis also has several internal buffers, all of which have names that start
with "Elvis ", such as (Elvis cut buffer x) and
(Elvis error list).
The :buffer! command (with a ! suffix) will list them all.
For the sake of brevity, elvis allows you to refer to cut buffers as
("x).
Similarly, the other internal buffers can be referred to via a " character
and the initial letter in each word of the full name, such as
("Eel) for (Elvis error list).
Commands which don't access the text, such as ":quit", don't allow any line addresses. Other commands, such as ":mark", only allow a single line address. Most commands, though, allow two line addresses; the command is applied to all lines between the two specified lines, inclusively. The tables below indicate how many line addresses each command allows.
Line addresses are always optional. The first line address of most commands usually defaults to the current line. The second line address usually defaults to be the same as the first line address. Exceptions are :write, :lpr, :global, and :vglobal, which act on all lines of the file by default, and :!, which acts on no lines by default.
If you use the visual V command to mark a range of lines, and then use the visual : command to execute a single ex command, then the default range affected by the ex command will be the visibly marked text.
Line addresses consist of an absolute part and a relative part. The absolute part of a line specifier may be either an explicit line number, a mark, a dot to denote the current line, a dollar sign to denote the last line of the file, or a forward or backward search. An explicit line number is simply a decimal number, expressed as a string of digits. A mark is typed in as an apostrophe followed by a letter. Marks must be set before they can be used. You can set a mark in visual command mode by typing "m" and a letter, or you can set it in ex command mode via the "mark" command. A forward search is typed in as a regular expression surrounded by slash characters; searching begins at the default line. A backward search is typed in as a regular expression surrounded by question marks; searching begins at the line before the default line.
If you omit the absolute part, then the default line is used.
The relative part of a line specifier is typed as a +
or - character followed by a decimal number.
The number is added to or subtracted from the absolute part of the line
specifier to produce the final line number.
As a special case, the % character may be used to specify
all lines of the file.
It is roughly equivalent to saying 1,$.
This can be a handy shortcut.
Here are some addressing examples, using the :p command:
COMMAND | ACTION -------------|------------------------------------------- :p | print the current line :37p | print line 37 :'gp | print the line which contains mark g :/foo/p | print the next line that contains "foo" :$p | print the last line of the buffer :20,30p | print lines 20 through 30 :1,$p | print all lines of the buffer :%p | print all lines of the buffer :(zot)%p | print all lines of the "zot" buffer :/foo/-2,+4p | print 5 lines around the next "foo"
The optional addresses are followed by the command name. Command names may be abbreviated. In the sections that follow, the command's full name is given with the optional part enclosed in square brackets.
Some commands allow a '!' character to appear immediately after the command name. The significance of the '!' varies from one command to another, but typically it forces the command to do something dangerous that it would ordinarily refuse to do. For example, :w file refuses to overwrite an existing file, but :w! file will do it.
Many commands allow (or even require) additional arguments. The descriptions below list which arguments each command accepts with optional commands denoted by square brackets. The most common argument types are:
Note: When entering a tab character into
a regular expression, you should type (Ctrl-V)(Tab). Otherwise
elvis will think the tab is intended to be used for
file name expansion.
Note: When entering a tab character into
the replacement text, you should type (Ctrl-V)(Tab). Otherwise
elvis will think the tab is intended to be used for
file name expansion.
This differs from TeX in two major ways:
\mathrel is more subtle than that.
\cr or \\ marks the end of each row, and
\hfil, \hfill, or & mark the end of a
column's data within a row.
TeX actually offers other commands to control the shape of the table, but
elvis doesn't support those commands.
$$ pair toggles between the "normal" font with standard text
filling, and the "fixed" font with lines displayed verbatim.
This is typically used for presenting longer command-line examples on lines
by themselves between paragraphs.
\item.
\item to mark it with an
asterisk, or by \item[bullet] to mark it with
something other than an asterisk.
{ ... }, like this:
Normal text {\tt Fixed-font text} Normal again.
$ character toggles between the "normal" font and the
"fixed" font.
This is often used for marking computer commands in the body of a paragraph.