path: root/runtime/doc/autocmd.txt

*autocmd.txt*   For Vim version 7.0aa.  Last change: 2004 Jun 30


		  VIM REFERENCE MANUAL    by Bram Moolenaar


Automatic commands					*autocommand*

For a basic explanation, see section |40.3| in the user manual.

1.  Introduction		|autocmd-intro|
2.  Defining autocommands	|autocmd-define|
3.  Removing autocommands	|autocmd-remove|
4.  Listing autocommands	|autocmd-list|
5.  Events			|autocmd-events|
6.  Patterns			|autocmd-patterns|
7.  Groups			|autocmd-groups|
8.  Executing autocommands	|autocmd-execute|
9.  Using autocommands		|autocmd-use|

{Vi does not have any of these commands}
{only when the |+autocmd| feature has not been disabled at compile time}

==============================================================================
1. Introduction						*autocmd-intro*

You can specify commands to be executed automatically for when reading or
writing a file, when entering or leaving a buffer or window, and when exiting
Vim.  For example, you can create an autocommand to set the 'cindent' option
for files matching *.c.  You can also use autocommands to implement advanced
features, such as editing compressed files (see |gzip-example|).  The usual
place to put autocommands is in your .vimrc or .exrc file.

							*E203* *E204* *E143*
WARNING: Using autocommands is very powerful, and may lead to unexpected side
effects.  Be careful not to destroy your text.
- It's a good idea to do some testing on an expendable copy of a file first.
  For example: If you use autocommands to decompress a file when starting to
  edit it, make sure that the autocommands for compressing when writing work
  correctly.
- Be prepared for an error halfway through (e.g., disk full).  Vim will mostly
  be able to undo the changes to the buffer, but you may have to clean up the
  changes to other files by hand (e.g., compress a file that has been
  decompressed).
- If the BufRead* events allow you to edit a compressed file, the FileRead*
  events should do the same (this makes recovery possible in some rare cases).
  It's a good idea to use the same autocommands for the File* and Buf* events
  when possible.

==============================================================================
2. Defining autocommands				*autocmd-define*

Note: The ":autocmd" command cannot be followed by another command, since any
'|' is considered part of the command.

							*:au* *:autocmd*
:au[tocmd] [group] {event} {pat} [nested] {cmd}
			Add {cmd} to the list of commands that Vim will
			execute automatically on {event} for a file matching
			{pat}.  Vim always adds the {cmd} after existing
			autocommands, so that the autocommands execute in the
			order in which they were given.  See |autocmd-nested|
			for [nested].

Note that special characters (e.g., "%", "<cword>") in the ":autocmd"
arguments are not expanded when the autocommand is defined.  These will be
expanded when the Event is recognized, and the {cmd} is executed.  The only
exception is that "<sfile>" is expanded when the autocmd is defined.  Example:
>
	:au BufNewFile,BufRead *.html so <sfile>:h/html.vim

Here Vim expands <sfile> to the name of the file containing this line.

When your .vimrc file is sourced twice, the autocommands will appear twice.
To avoid this, put this command in your .vimrc file, before defining
autocommands: >

	:autocmd!	" Remove ALL autocommands for the current group.

If you don't want to remove all autocommands, you can instead use a variable
to ensure that Vim includes the autocommands only once: >

	:if !exists("autocommands_loaded")
	:  let autocommands_loaded = 1
	:  au ...
	:endif

When the [group] argument is not given, Vim uses the current group (as defined
with ":augroup"); otherwise, Vim uses the group defined with [group].  Note
that [group] must have been defined before.  You cannot define a new group
with ":au group ..."; use ":augroup" for that.

While testing autocommands, you might find the 'verbose' option to be useful: >
	:set verbose=9
This setting makes Vim echo the autocommands as it executes them.

When defining an autocommand in a script, it will be able to call functions
local to the script and use mappings local to the script.  When the event is
triggered and the command executed, it will run in the context of the script
it was defined in.  This matters if |<SID>| is used in a command.

When executing the commands, the messages from one command overwrites a
previous message.  This is different from when executing the commands
manually.  Mostly the screen will not scroll up, thus there is no hit-enter
prompt.  When one command outputs two messages this can happen anyway.

==============================================================================
3. Removing autocommands				*autocmd-remove*

:au[tocmd]! [group] {event} {pat} [nested] {cmd}
			Remove all autocommands associated with {event} and
			{pat}, and add the command {cmd}.  See
			|autocmd-nested| for [nested].

:au[tocmd]! [group] {event} {pat}
			Remove all autocommands associated with {event} and
			{pat}.

:au[tocmd]! [group] * {pat}
			Remove all autocommands associated with {pat} for all
			events.

:au[tocmd]! [group] {event}
			Remove ALL autocommands for {event}.

:au[tocmd]! [group]	Remove ALL autocommands.

When the [group] argument is not given, Vim uses the current group (as defined
with ":augroup"); otherwise, Vim uses the group defined with [group].

==============================================================================
4. Listing autocommands					*autocmd-list*

:au[tocmd] [group] {event} {pat}
			Show the autocommands associated with {event} and
			{pat}.

:au[tocmd] [group] * {pat}
			Show the autocommands associated with {pat} for all
			events.

:au[tocmd] [group] {event}
			Show all autocommands for {event}.

:au[tocmd] [group]	Show all autocommands.

If you provide the [group] argument, Vim lists only the autocommands for
[group]; otherwise, Vim lists the autocommands for ALL groups.  Note that this
argument behavior differs from that for defining and removing autocommands.

==============================================================================
5. Events					*autocmd-events* *E215* *E216*

					*autocommand-events* *{event}*
Vim recognizes the following events.  Vim ignores the case of event names
(e.g., you can use "BUFread" or "bufread" instead of "BufRead").

							*BufNewFile*
BufNewFile			When starting to edit a file that doesn't
				exist.  Can be used to read in a skeleton
				file.
						*BufReadPre* *E200* *E201*
BufReadPre			When starting to edit a new buffer, before
				reading the file into the buffer.  Not used
				if the file doesn't exist.
						*BufRead* *BufReadPost*
BufRead or BufReadPost		When starting to edit a new buffer, after
				reading the file into the buffer, before
				executing the modelines.  See |BufWinEnter|
				for when you need to do something after
				processing the modelines.
				This does NOT work for ":r file".  Not used
				when the file doesn't exist.  Also used after
				successfully recovering a file.
							*BufReadCmd*
BufReadCmd			Before starting to edit a new buffer.  Should
				read the file into the buffer. |Cmd-event|
							*BufFilePre*
BufFilePre			Before changing the name of the current buffer
				with the ":file" or ":saveas" command.
							*BufFilePost*
BufFilePost			After changing the name of the current buffer
				with the ":file" or ":saveas" command.
							*FileReadPre*
FileReadPre			Before reading a file with a ":read" command.
							*FileReadPost*
FileReadPost			After reading a file with a ":read" command.
				Note that Vim sets the '[ and '] marks to the
				first and last line of the read.  This can be
				used to operate on the lines just read.
							*FileReadCmd*
FileReadCmd			Before reading a file with a ":read" command.
				Should do the reading of the file. |Cmd-event|
							*FilterReadPre* *E135*
FilterReadPre			Before reading a file from a filter command.
				Vim checks the pattern against the name of
				the current buffer, not the name of the
				temporary file that is the output of the
				filter command.
							*FilterReadPost*
FilterReadPost			After reading a file from a filter command.
				Vim checks the pattern against the name of
				the current buffer as with FilterReadPre.
							*FileType*
FileType			When the 'filetype' option has been set.
				<afile> can be used for the name of the file
				where this option was set, and <amatch> for
				the new value of 'filetype'.
				See |filetypes|.
							*Syntax*
Syntax				When the 'syntax' option has been set.
				<afile> can be used for the name of the file
				where this option was set, and <amatch> for
				the new value of 'syntax'.
				See |:syn-on|.
							*StdinReadPre*
StdinReadPre			Before reading from stdin into the buffer.
				Only used when the "-" argument was used when
				Vim was started |--|.
							*StdinReadPost*
StdinReadPost			After reading from the stdin into the buffer,
				before executing the modelines.  Only used
				when the "-" argument was used when Vim was
				started |--|.
						*BufWrite* *BufWritePre*
BufWrite or BufWritePre		Before writing the whole buffer to a file.
							*BufWritePost*
BufWritePost			After writing the whole buffer to a file
				(should undo the commands for BufWritePre).
							*BufWriteCmd*
BufWriteCmd			Before writing the whole buffer to a file.
				Should do the writing of the file and reset
				'modified' if successful.  The buffer contents
				should not be changed.  |Cmd-event|
							*FileWritePre*
FileWritePre			Before writing to a file, when not writing the
				whole buffer.
							*FileWritePost*
FileWritePost			After writing to a file, when not writing the
				whole buffer.
							*FileWriteCmd*
FileWriteCmd			Before writing to a file, when not writing the
				whole buffer.  Should do the writing to the
				file.  Should not change the buffer.
				|Cmd-event|
							*FileAppendPre*
FileAppendPre			Before appending to a file.
							*FileAppendPost*
FileAppendPost			After appending to a file.
							*FileAppendCmd*
FileAppendCmd			Before appending to a file.  Should do the
				appending to the file. |Cmd-event|
							*FilterWritePre*
FilterWritePre			Before writing a file for a filter command or
				making a diff.
				Vim checks the pattern against the name of
				the current buffer, not the name of the
				temporary file that is the output of the
				filter command.
							*FilterWritePost*
FilterWritePost			After writing a file for a filter command or
				making a diff.
				Vim checks the pattern against the name of
				the current buffer as with FilterWritePre.
							*FileChangedShell*
FileChangedShell		When Vim notices that the modification time of
				a file has changed since editing started.
				Also when the file attributes of the file
				change. |timestamp|
				Mostly triggered after executing a shell
				command, but also with a |:checktime| command
				or when Vim regains input focus.
				This autocommand is triggered for each changed
				file.  It is not used when 'autoread' is set
				and the buffer was not changed.  If a
				FileChangedShell autocommand is present the
				warning message and prompt is not given.
				This is useful for reloading related buffers
				which are affected by a single command.
				NOTE: When this autocommand is executed, the
				current buffer "%" may be different from the
				buffer that was changed "<afile>".
				NOTE: The commands must not change the current
				buffer, jump to another buffer or delete a
				buffer.  *E246*
				NOTE: This event never nests, to avoid an
				endless loop.  This means that while executing
				commands for the FileChangedShell event no
				other FileChangedShell event will be
				triggered.
							*FileChangedRO*
FileChangedRO			Before making the first change to a read-only
				file.  Can be used to check-out the file from
				a source control system.  Not triggered when
				the change was caused by an autocommand.
				WARNING: This event is triggered when making a
				change, just before the change is applied to
				the text.  If the autocommand moves the cursor
				the effect of the change is undefined.
							*FocusGained*
FocusGained			When Vim got input focus.  Only for the GUI
				version and a few console versions where this
				can be detected.
							*FocusLost*
FocusLost			When Vim lost input focus.  Only for the GUI
				version and a few console versions where this
				can be detected.  May also happen when a
				dialog pops up.
							*FuncUndefined*
FuncUndefined			When a user function is used but it isn't
				defined.  Useful for defining a function only
				when it's used.  Both <amatch> and <afile> are
				set to the name of the function.
							*CursorHold*
CursorHold			When the user doesn't press a key for the time
				specified with 'updatetime'.  Not re-triggered
				until the user has pressed a key (i.e. doesn't
				fire every 'updatetime' ms if you leave Vim to
				make some coffee. :)  See |CursorHold-example|
				for previewing tags.
				This event is only triggered in Normal mode.
				Note: Interactive commands cannot be used for
				this event.  There is no hit-enter prompt,
				the screen is updated directly (when needed).
				Note: In the future there will probably be
				another option to set the time.
				Hint: to force an update of the status lines
				use: >
					:let &ro = &ro
<				{only on Amiga, Unix, Win32, MSDOS and all GUI
				versions}
							*BufEnter*
BufEnter			After entering a buffer.  Useful for setting
				options for a file type.  Also executed when
				starting to edit a buffer, after the
				BufReadPost autocommands.
							*BufLeave*
BufLeave			Before leaving to another buffer.  Also when
				leaving or closing the current window and the
				new current window is not for the same buffer.
				Not used for ":qa" or ":q" when exiting Vim.
							*BufWinEnter*
BufWinEnter			After a buffer is displayed in a window.  This
				can be when the buffer is loaded (after
				processing the modelines), when a hidden
				buffer is displayed in a window (and is no
				longer hidden) or a buffer already visible in
				a window is also displayed in another window.
							*BufWinLeave*
BufWinLeave			Before a buffer is removed from a window.
				Not when it's still visible in another window.
				Also triggered when exiting.  It's triggered
				before BufUnload or BufHidden.
				NOTE: When this autocommand is executed, the
				current buffer "%" may be different from the
				buffer being unloaded "<afile>".
							*BufUnload*
BufUnload			Before unloading a buffer.  This is when the
				text in the buffer is going to be freed.  This
				may be after a BufWritePost and before a
				BufDelete.  Also used for all buffers that are
				loaded when Vim is going to exit.
				NOTE: When this autocommand is executed, the
				current buffer "%" may be different from the
				buffer being unloaded "<afile>".
							*BufHidden*
BufHidden			Just after a buffer has become hidden.  That
				is, when there are no longer windows that show
				the buffer, but the buffer is not unloaded or
				deleted.  Not used for ":qa" or ":q" when
				exiting Vim.
				NOTE: When this autocommand is executed, the
				current buffer "%" may be different from the
				buffer being unloaded "<afile>".
							*BufNew*
BufNew				Just after creating a new buffer.  Also used
				just after a buffer has been renamed.  When
				the buffer is added to the buffer list BufAdd
				will be triggered too.
				NOTE: When this autocommand is executed, the
				current buffer "%" may be different from the
				buffer being created "<afile>".
							*BufCreate* *BufAdd*
BufAdd or BufCreate		Just after creating a new buffer which is
				added to the buffer list, or adding a buffer
				to the buffer list.
				Also used just after a buffer in the buffer
				list has been renamed.
				The BufCreate event is for historic reasons.
				NOTE: When this autocommand is executed, the
				current buffer "%" may be different from the
				buffer being created "<afile>".
							*BufDelete*
BufDelete			Before deleting a buffer from the buffer list.
				The BufUnload may be called first (if the
				buffer was loaded).
				Also used just before a buffer in the buffer
				list is renamed.
				NOTE: When this autocommand is executed, the
				current buffer "%" may be different from the
				buffer being deleted "<afile>".
							*BufWipeout*
BufWipeout			Before completely deleting a buffer.  The
				BufUnload and BufDelete events may be called
				first (if the buffer was loaded and was in the
				buffer list).  Also used just before a buffer
				is renamed (also when it's not in the buffer
				list).
				NOTE: When this autocommand is executed, the
				current buffer "%" may be different from the
				buffer being deleted "<afile>".
							*WinEnter*
WinEnter			After entering another window.  Not done for
				the first window, when Vim has just started.
				Useful for setting the window height.
				If the window is for another buffer, Vim
				executes the BufEnter autocommands after the
				WinEnter autocommands.
				Note: When using ":split fname" the WinEnter
				event is triggered after the split but before
				the file "fname" is loaded.
							*WinLeave*
WinLeave			Before leaving a window.  If the window to be
				entered next is for a different buffer, Vim
				executes the BufLeave autocommands before the
				WinLeave autocommands (but not for ":new").
				Not used for ":qa" or ":q" when exiting Vim.
							*CmdwinEnter*
CmdwinEnter			After entering the command-line window.
				Useful for setting options specifically for
				this special type of window.  This is
				triggered _instead_ of BufEnter and WinEnter.
				<afile> is set to a single character,
				indicating the type of command-line.
				|cmdwin-char|
							*CmdwinLeave*
CmdwinLeave			Before leaving the command-line window.
				Useful to clean up any global setting done
				with CmdwinEnter.  This is triggered _instead_
				of BufLeave and WinLeave.
				<afile> is set to a single character,
				indicating the type of command-line.
				|cmdwin-char|
							*GUIEnter*
GUIEnter			After starting the GUI successfully, and after
				opening the window.  It is triggered before
				VimEnter when using gvim.  Can be used to
				position the window from a .gvimrc file: >
	:autocmd GUIEnter * winpos 100 50
<							*VimEnter*
VimEnter			After doing all the startup stuff, including
				loading .vimrc files, executing the "-c cmd"
				arguments, creating all windows and loading
				the buffers in them.
							*VimLeavePre*
VimLeavePre			Before exiting Vim, just before writing the
				.viminfo file.  This is executed only once,
				if there is a match with the name of what
				happens to be the current buffer when exiting.
				Mostly useful with a "*" pattern. >
	:autocmd VimLeavePre * call CleanupStuff()
<				To detect an abnormal exit use |v:dying|.
							*VimLeave*
VimLeave			Before exiting Vim, just after writing the
				.viminfo file.  Executed only once, like
				VimLeavePre.
				To detect an abnormal exit use |v:dying|.
							*EncodingChanged*
EncodingChanged			Fires off when the 'encoding' option is
				changed.  Useful to set up fonts, for example.
							*InsertEnter*
InsertEnter			When starting Insert mode.  Also for Replace
				mode and Virtual Replace mode.  The
				|v:insertmode| variable indicates the mode.
				Be careful not to move the cursor or do
				anything else that the user does not expect.
							*InsertChange*
InsertChange			When typing <Insert> while in Insert or
				Replace mode.  The |v:insertmode| variable
				indicates the new mode.
				Be careful not to move the cursor or do
				anything else that the user does not expect.
							*InsertLeave*
InsertLeave			When leaving Insert mode.  Also when using
				CTRL-O |i_CTRL-O|.
							*FileEncoding*
FileEncoding			Obsolete.  It still works and is equivalent
				to |EncodingChanged|.
							*RemoteReply*
RemoteReply			When a reply from a Vim that functions as
				server was received |server2client()|.
				<amatch> is equal to the {serverid} from which
				the reply was sent, and <afile> is the actual
				reply string.
				Note that even if an autocommand is defined,
				the reply should be read with |remote_read()|
				to consume it.
							*TermChanged*
TermChanged			After the value of 'term' has changed.  Useful
				for re-loading the syntax file to update the
				colors, fonts and other terminal-dependent
				settings.  Executed for all loaded buffers.
							*TermResponse*
TermResponse			After the response to |t_RV| is received from
				the terminal.  The value of |v:termresponse|
				can be used to do things depending on the
				terminal version.
							*UserGettingBored*
UserGettingBored		When the user hits CTRL-C.  Just kidding! :-)
							*User*
User				Never executed automatically.  To be used for
				autocommands that are only executed with
				":doautocmd".

You can specify a comma-separated list of event names.  No white space can be
used in this list.  The command applies to all the events in the list.

For READING FILES there are four kinds of events possible:
	BufNewFile			starting to edit a non-existent file
	BufReadPre	BufReadPost	starting to edit an existing file
	FilterReadPre	FilterReadPost	read the temp file with filter output
	FileReadPre	FileReadPost	any other file read
Vim uses only one of these four kinds when reading a file.  The "Pre" and
"Post" events are both triggered, before and after reading the file.

Note that the autocommands for the *ReadPre events and all the Filter events
are not allowed to change the current buffer (you will get an error message if
this happens).  This is to prevent the file to be read into the wrong buffer.

Note that the 'modified' flag is reset AFTER executing the BufReadPost
and BufNewFile autocommands.  But when the 'modified' option was set by the
autocommands, this doesn't happen.

You can use the 'eventignore' option to ignore a number of events or all
events.

==============================================================================
6. Patterns					*autocmd-patterns* *{pat}*

The file pattern {pat} is tested for a match against the file name in one of
two ways:
1. When there is no '/' in the pattern, Vim checks for a match against only
   the tail part of the file name (without its leading directory path).
2. When there is a '/' in the pattern,  Vim checks for a match against the
   both short file name (as you typed it) and the full file name (after
   expanding it to a full path and resolving symbolic links).

Examples: >
	:autocmd BufRead *.txt		set et
Set the 'et' option for all text files. >

	:autocmd BufRead /vim/src/*.c	set cindent
Set the 'cindent' option for C files in the /vim/src directory. >

	:autocmd BufRead /tmp/*.c	set ts=5
If you have a link from "/tmp/test.c" to "/home/nobody/vim/src/test.c", and
you start editing "/tmp/test.c", this autocommand will match.

Note:  To match part of a path, but not from the root directory, use a '*' as
the first character.  Example: >
	:autocmd BufRead */doc/*.txt	set tw=78
This autocommand will for example be executed for "/tmp/doc/xx.txt" and
"/usr/home/piet/doc/yy.txt".  The number of directories does not matter here.


The file name that the pattern is matched against is after expanding
wildcards.  Thus is you issue this command: >
	:e $ROOTDIR/main.$EXT
The argument is first expanded to: >
	/usr/root/main.py
Before it's matched with the pattern of the autocommand.  Careful with this
when using events like FileReadCmd, the value of <amatch> may not be what you
expect.


Environment variables can be used in a pattern: >
	:autocmd BufRead $VIMRUNTIME/doc/*.txt  set expandtab
And ~ can be used for the home directory (if $HOME is defined): >
	:autocmd BufWritePost ~/.vimrc   so ~/.vimrc
	:autocmd BufRead ~archive/*      set readonly
The environment variable is expanded when the autocommand is defined, not when
the autocommand is executed.  This is different from the command!

							*file-pattern*
The pattern is interpreted like mostly used in file names:
	*	matches any sequence of characters
	?	matches any single character
	\?	matches a '?'
	.	matches a '.'
	~	matches a '~'
	,	separates patterns
	\,	matches a ','
	{ }	like \( \) in a |pattern|
	,	inside { }: like \| in a |pattern|
	\	special meaning like in a |pattern|
	[ch]	matches 'c' or 'h'
	[^ch]   match any character but 'c' and 'h'

Note that for all systems the '/' character is used for path separator (even
MS-DOS and OS/2).  This was done because the backslash is difficult to use
in a pattern and to make the autocommands portable across different systems.


Matching with the pattern is done when an e