# Vim documentation: autocmd

main help file

    *autocmd.txt*   For Vim version 8.1.  Last change: 2018 May 03

    		  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.  Buffer-local autocommands	|autocmd-buflocal|
    8.  Groups			|autocmd-groups|
    9.  Executing autocommands	|autocmd-execute|
    10. Using autocommands		|autocmd-use|
    11. Disabling autocommands	|autocmd-disable|

    {Vi does not have any of these commands}

    ==============================================================================

    1. Introduction						*autocmd-intro*

    You can specify commands to be executed automatically 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* *E855* *E937* *E952*
    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*

    							*: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} |autocmd-patterns|.
    			Note: A quote character is seen as argument to the
    			:autocmd and won't start a comment.
    			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].

    The special pattern <buffer> or <buffer=N> defines a buffer-local autocommand.
    See |autocmd-buflocal|.

    Note: The ":autocmd" command can only be followed by another command when the
    '|' appears before {cmd}.  This works:
    	:augroup mine | au! BufRead | augroup END
    But this sees "augroup" as part of the defined command:
    	:augroup mine | au! BufRead * | augroup END
    	:augroup mine | au BufRead * set tw=70 | augroup END
    Instead you can put the group name into the command:
    	:au! mine BufRead *
    	:au mine BufRead * set tw=70
    Or use `:execute`:
    	:augroup mine | exe "au! BufRead *" | augroup END
    	:augroup mine | exe "au BufRead * set tw=70" | augroup END

    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.

    `:autocmd` adds to the list of autocommands regardless of whether they are
    already present.  When your .vimrc file is sourced twice, the autocommands
    will appear twice.  To avoid this, define your autocommands in a group, so
    that you can easily clear them:

    	augroup vimrc
    	  " Remove all vimrc autocommands
    	  autocmd!
    	  au BufNewFile,BufRead *.html so <sfile>:h/html.vim
    	augroup END

    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 message 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}.
    			Warning: You should not do this without a group for
    			|BufRead| and other common events, it can break
    			plugins, syntax highlighting, etc.

    :au[tocmd]! [group]	Remove ALL autocommands.
    			Note: a quote will be seen as argument to the :autocmd
    			and won't start a comment.
    			Warning: You should normally not do this without a
    			group, it breaks plugins, syntax highlighting, etc.

    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.

    In order to list buffer-local autocommands, use a pattern in the form <buffer>
    or <buffer=N>.  See |autocmd-buflocal|.

    							*:autocmd-verbose*
    When 'verbose' is non-zero, listing an autocommand will also display where it
    was last defined. Example:

        :verbose autocmd BufEnter
        FileExplorer  BufEnter
    	*	  call s:LocalBrowse(expand("<amatch>"))
    	    Last set from /usr/share/vim/vim-7.0/plugin/NetrwPlugin.vim

    See |:verbose-cmd| for more information.

    ==============================================================================

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

    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.

    					*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").

    First an overview by function with a short explanation.  Then the list
    alphabetically with full explanations |autocmd-events-abc|.

    Name			triggered by

    	Reading
    |BufNewFile|		starting to edit a file that doesn't exist
    |BufReadPre|		starting to edit a new buffer, before reading the file
    |BufRead|		starting to edit a new buffer, after reading the file
    |BufReadPost|		starting to edit a new buffer, after reading the file
    |BufReadCmd|		before starting to edit a new buffer |Cmd-event|

    |FileReadPre|		before reading a file with a ":read" command
    |FileReadPost|		after reading a file with a ":read" command
    |FileReadCmd|		before reading a file with a ":read" command |Cmd-event|

    |FilterReadPre|		before reading a file from a filter command
    |FilterReadPost|	after reading a file from a filter command

    |StdinReadPre|		before reading from stdin into the buffer
    |StdinReadPost|		After reading from the stdin into the buffer

    	Writing
    |BufWrite|		starting to write the whole buffer to a file
    |BufWritePre|		starting to write the whole buffer to a file
    |BufWritePost|		after writing the whole buffer to a file
    |BufWriteCmd|		before writing the whole buffer to a file |Cmd-event|

    |FileWritePre|		starting to write part of a buffer to a file
    |FileWritePost|		after writing part of a buffer to a file
    |FileWriteCmd|		before writing part of a buffer to a file |Cmd-event|

    |FileAppendPre|		starting to append to a file
    |FileAppendPost|	after appending to a file
    |FileAppendCmd|		before appending to a file |Cmd-event|

    |FilterWritePre|	starting to write a file for a filter command or diff
    |FilterWritePost|	after writing a file for a filter command or diff

    	Buffers
    |BufAdd|		just after adding a buffer to the buffer list
    |BufCreate|		just after adding a buffer to the buffer list
    |BufDelete|		before deleting a buffer from the buffer list
    |BufWipeout|		before completely deleting a buffer
    |TerminalOpen|		after a terminal buffer was created

    |BufFilePre|		before changing the name of the current buffer
    |BufFilePost|		after changing the name of the current buffer

    |BufEnter|		after entering a buffer
    |BufLeave|		before leaving to another buffer
    |BufWinEnter|		after a buffer is displayed in a window
    |BufWinLeave|		before a buffer is removed from a window

    |BufUnload|		before unloading a buffer
    |BufHidden|		just after a buffer has become hidden
    |BufNew|		just after creating a new buffer

    |SwapExists|		detected an existing swap file

    	Options
    |FileType|		when the 'filetype' option has been set
    |Syntax|		when the 'syntax' option has been set
    |EncodingChanged|	after the 'encoding' option has been changed
    |TermChanged|		after the value of 'term' has changed
    |OptionSet|		after setting any option

    	Startup and exit
    |VimEnter|		after doing all the startup stuff
    |GUIEnter|		after starting the GUI successfully
    |GUIFailed|		after starting the GUI failed
    |TermResponse|		after the terminal response to |t_RV| is received

    |QuitPre|		when using `:quit`, before deciding whether to exit
    |ExitPre|		when using a command that may make Vim exit
    |VimLeavePre|		before exiting Vim, before writing the viminfo file
    |VimLeave|		before exiting Vim, after writing the viminfo file

    	Various
    |FileChangedShell|	Vim notices that a file changed since editing started
    |FileChangedShellPost|	After handling a file changed since editing started
    |FileChangedRO|		before making the first change to a read-only file

    |DirChanged|		after the working directory has changed

    |ShellCmdPost|		after executing a shell command
    |ShellFilterPost|	after filtering with a shell command

    |CmdUndefined|		a user command is used but it isn't defined
    |FuncUndefined|		a user function is used but it isn't defined
    |SpellFileMissing|	a spell file is used but it can't be found
    |SourcePre|		before sourcing a Vim script
    |SourceCmd|		before sourcing a Vim script |Cmd-event|

    |VimResized|		after the Vim window size changed
    |FocusGained|		Vim got input focus
    |FocusLost|		Vim lost input focus
    |CursorHold|		the user doesn't press a key for a while
    |CursorHoldI|		the user doesn't press a key for a while in Insert mode
    |CursorMoved|		the cursor was moved in Normal mode
    |CursorMovedI|		the cursor was moved in Insert mode

    |WinNew|		after creating a new window
    |TabNew|		after creating a new tab page
    |TabClosed|		after closing a tab page
    |WinEnter|		after entering another window
    |WinLeave|		before leaving a window
    |TabEnter|		after entering another tab page
    |TabLeave|		before leaving a tab page
    |CmdwinEnter|		after entering the command-line window
    |CmdwinLeave|		before leaving the command-line window

    |CmdlineChanged|	after a change was made to the command-line text
    |CmdlineEnter|		after the cursor moves to the command line
    |CmdlineLeave|		before the cursor leaves the command line

    |InsertEnter|		starting Insert mode
    |InsertChange|		when typing <Insert> while in Insert or Replace mode
    |InsertLeave|		when leaving Insert mode
    |InsertCharPre|		when a character was typed in Insert mode, before
    			inserting it

    |TextChanged|		after a change was made to the text in Normal mode
    |TextChangedI|		after a change was made to the text in Insert mode
    			when popup menu is not visible
    |TextChangedP|		after a change was made to the text in Insert mode
    			when popup menu visible
    |TextYankPost|		after text is yanked or deleted

    |ColorSchemePre|	before loading a color scheme
    |ColorScheme|		after loading a color scheme

    |RemoteReply|		a reply from a server Vim was received

    |QuickFixCmdPre|	before a quickfix command is run
    |QuickFixCmdPost|	after a quickfix command is run

    |SessionLoadPost|	after loading a session file

    |MenuPopup|		just before showing the popup menu
    |CompleteDone|		after Insert mode completion is done

    |User|			to be used in combination with ":doautocmd"

    The alphabetical list of autocommand events:		*autocmd-events-abc*

    							*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>" and "<abuf>".
    				Don't change to another buffer, it will cause
    				problems.

    							*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.

    							*BufFilePost*
    BufFilePost			After changing the name of the current buffer
    				with the ":file" or ":saveas" command.

    							*BufFilePre*
    BufFilePre			Before changing the name of the current buffer
    				with the ":file" or ":saveas" command.

    							*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>".

    							*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.

    							*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>".

    							*BufNewFile*
    BufNewFile			When starting to edit a file that doesn't
    				exist.  Can be used to read in a skeleton
    				file.

    						*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.
    				Also triggered for the filetypedetect group
    				when executing ":filetype detect" and when
    				writing an unnamed buffer in a way that the
    				buffer gets a name.

    							*BufReadCmd*
    BufReadCmd			Before starting to edit a new buffer.  Should
    				read the file into the buffer. |Cmd-event|

    						*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.

    							*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>".
    				Don't change to another buffer or window, it
    				will cause problems!
    				When exiting and v:dying is 2 or more this
    				event is not triggered.

    							*BufWinEnter*
    BufWinEnter			After a buffer is displayed in a window.  This
    				can be when the buffer is loaded (after
    				processing the modelines) or when a hidden
    				buffer is displayed in a window (and is no
    				longer hidden).
    				Does not happen for |:split| without
    				arguments, since you keep editing the same
    				buffer, or ":split" with a file that's already
    				open in a window, because it re-uses an
    				existing buffer.  But it does happen for a
    				":split" with the name of the current buffer,
    				since it reloads that buffer.
    				Does not happen for a terminal window, because
    				it starts in Terminal-Job mode and Normal mode
    				commands won't work. Use |TerminalOpen| instead.

    							*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>".
    				When exiting and v:dying is 2 or more this
    				event is not triggered.

    							*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>".
    				Don't change to another buffer, it will cause
    				problems.

    						*BufWrite* *BufWritePre*
    BufWrite or BufWritePre		Before writing the whole buffer to a file.

    							*BufWriteCmd*
    BufWriteCmd			Before writing the whole buffer to a file.
    				Should do the writing of the file and reset
    				'modified' if successful, unless '+' is in
    				'cpo' and writing to another file |cpo-+|.
    				The buffer contents should not be changed.
    				When the command resets 'modified' the undo
    				information is adjusted to mark older undo
    				states as 'modified', like |:write| does.
    				|Cmd-event|

    							*BufWritePost*
    BufWritePost			After writing the whole buffer to a file
    				(should undo the commands for BufWritePre).

    							*CmdUndefined*
    CmdUndefined			When a user command is used but it isn't
    				defined.  Useful for defining a command only
    				when it's used.  The pattern is matched
    				against the command name.  Both <amatch> and
    				<afile> are set to the name of the command.
    				NOTE: Autocompletion won't work until the
    				command is defined.  An alternative is to
    				always define the user command and have it
    				invoke an autoloaded function.  See |autoload|.

    							*CmdlineChanged*
    CmdlineChanged			After a change was made to the text in the
    				command line.  Be careful not to mess up
    				the command line, it may cause Vim to lock up.
    				<afile> is set to a single character,
    				indicating the type of command-line.
    				|cmdwin-char|

    							*CmdlineEnter*
    CmdlineEnter			After moving the cursor to the command line,
    				where the user can type a command or search
    				string.
    				<afile> is set to a single character,
    				indicating the type of command-line.
    				|cmdwin-char|

    							*CmdlineLeave*
    CmdlineLeave			Before leaving the command line.
    				Also when abandoning the command line, after
    				typing CTRL-C or <Esc>.
    				When the commands result in an error the
    				command line is still executed.
    				<afile> is set to a single character,
    				indicating the type of command-line.
    				|cmdwin-char|

    							*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|

    							*ColorScheme*
    ColorScheme			After loading a color scheme. |:colorscheme|
    				The pattern is matched against the
    				colorscheme name. <afile> can be used for the
    				name of the actual file where this option was
    				set, and <amatch> for the new colorscheme
    				name.

    							*ColorSchemePre*
    ColorSchemePre			Before loading a color scheme. |:colorscheme|
    				Useful to setup removing things added by a
    				color scheme, before another one is loaded.

    							*CompleteDone*
    CompleteDone			After Insert mode completion is done.  Either
    				when something was completed or abandoning
    				completion. |ins-completion|
    				The |v:completed_item| variable contains
    				information about the completed item.

    							*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.
    				It is not triggered when waiting for a command
    				argument to be typed, or a movement after an
    				operator.
    				While recording the CursorHold event is not
    				triggered. |q|

    							*<CursorHold>*
    				Internally the autocommand is triggered by the
    				<CursorHold> key. In an expression mapping
    				|getchar()| may see this character.

    				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}

    							*CursorHoldI*
    CursorHoldI			Just like CursorHold, but in Insert mode.
    				Not triggered when waiting for another key,
    				e.g. after CTRL-V, and not when in CTRL-X mode
    				|insert_expand|.

    							*CursorMoved*
    CursorMoved			After the cursor was moved in Normal or Visual
    				mode.  Also when the text of the cursor line
    				has been changed, e.g., with "x", "rx" or "p".
    				Not triggered when there is typeahead or when
    				an operator is pending.
    				For an example see |match-parens|.
    				Careful: This is triggered very often, don't
    				do anything that the user does not expect or
    				that is slow.

    							*CursorMovedI*
    CursorMovedI			After the cursor was moved in Insert mode.
    				Not triggered when the popup menu is visible.
    				Otherwise the same as CursorMoved.

    							*EncodingChanged*
    EncodingChanged			Fires off after the 'encoding' option has been
    				changed.  Useful to set up fonts, for example.

    							*FileAppendCmd*
    FileAppendCmd			Before appending to a file.  Should do the
    				appending to the file.  Use the '[ and ']
    				marks for the range of lines.|Cmd-eventYXXY

    							*FileAppendPost*
    FileAppendPost			After appending to a file.

    							*FileAppendPre*
    FileAppendPre			Before appending to a file.  Use the '[ and ']
    				marks for the range of lines.

    							*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.
    				This event is triggered when making the first
    				change in a buffer or the first change after
    				'readonly' was set, just before the change is
    				applied to the text.
    				WARNING: If the autocommand moves the cursor
    				the effect of the change is undefined.

    							*E788*
    				It is not allowed to change to another buffer
    				here.  You can reload the buffer but not edit
    				another one.

    							*E881*
    				If the number of lines changes saving for undo
    				may fail and the change will be aborted.

    							*DirChanged*
    DirChanged			The working directory has changed in response
    				to the |:cd| or |:lcd| commands, or as a
    				result of the 'autochdir' option.
    				The pattern can be:
    					"window" to trigger on `:lcd
    					"global" to trigger on `:cd`
    					"auto"   to trigger on 'autochdir'.
    					"drop"	 to trigger on editing a file
    				<afile> is set to the new directory name.

    							*ExitPre*
    ExitPre				When using `:quit`, `:wq` in a way it makes
    				Vim exit, or using `:qall`, just after
    				|QuitPre|.  Can be used to close any
    				non-essential window.

    							*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 or when the size of the file changes.
    				|timestamp|
    				Mostly triggered after executing a shell
    				command, but also with a |:checktime| command
    				or when gvim 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.
    				The |v:fcs_reason| variable is set to indicate
    				what happened and |v:fcs_choice| can be used
    				to tell Vim what to do next.
    				NOTE: When this autocommand is executed, the
    				current buffer "%" may be different from the
    				buffer that was changed, which is in "<afile>".
    				NOTE: The commands must not change the current
    				buffer, jump to another buffer or delete a

    				buffer.  *E246* *E811*
    				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.

    							*FileChangedShellPost*
    FileChangedShellPost		After handling a file that was changed outside
    				of Vim.  Can be used to update the statusline.

    							*FileEncoding*
    FileEncoding			Obsolete.  It still works and is equivalent
    				to |EncodingChanged|.

    							*FileReadCmd*
    FileReadCmd			Before reading a file with a ":read" command.
    				Should do the reading of the file. |Cmd-event|

    							*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.

    							*FileReadPre*
    FileReadPre			Before reading a file with a ":read" command.

    							*FileType*
    FileType			When the 'filetype' option has been set.  The
    				pattern is matched against the filetype.
    				<afile> can be used for the name of the file
    				where this option was set, and <amatch> for
    				the new value of 'filetype'.  Navigating to
    				another window or buffer is not allowed.
    				See |filetypes|.

    							*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.  Use the
    				'[ and '] marks for the range of lines.
    				|Cmd-event|

    							*FileWritePost*
    FileWritePost			After writing to a file, when not writing the
    				whole buffer.

    							*FileWritePre*
    FileWritePre			Before writing to a file, when not writing the
    				whole buffer.  Use the '[ and '] marks for the
    				range of lines.

    							*FilterReadPost*
    FilterReadPost			After reading a file from a filter command.
    				Vim checks the pattern against the name of
    				the current buffer as with FilterReadPre.
    				Not triggered when 'shelltemp' is off.

    							*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.
    				Not triggered when 'shelltemp' is off.

    							*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.
    				Not triggered when 'shelltemp' is off.

    							*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.
    				Not triggered when 'shelltemp' is off.

    							*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.  The pattern is matched
    				against the function name.  Both <amatch> and
    				<afile> are set to the name of the function.
    				NOTE: When writing Vim scripts a better
    				alternative is to use an autoloaded function.
    				See |autoload-functions|.

    							*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

     							*GUIFailed*
    GUIFailed			After starting the GUI failed.  Vim may
    				continue to run in the terminal, if possible
    				(only on Unix and alikes, when connecting the
    				X server fails).  You may want to quit Vim:
    	:autocmd GUIFailed * qall

     							*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.

    							*InsertCharPre*
    InsertCharPre			When a character is typed in Insert mode,
    				before inserting the char.
    				The |v:char| variable indicates the char typed
    				and can be changed during the event to insert
    				a different character.  When |v:char| is set
    				to more than one character this text is
    				inserted literally.
    				It is not allowed to change the text |textlock|.
    				The event is not triggered when 'paste' is
    				set. {only with the +eval feature}

    							*InsertEnter*
    InsertEnter			Just before starting Insert mode.  Also for
    				Replace mode and Virtual Replace mode.  The
    				|v:insertmode| variable indicates the mode.
    				Be careful not to do anything else that the
    				user does not expect.
    				The cursor is restored afterwards.  If you do
    				not want that set |v:char| to a non-empty
    				string.

    							*InsertLeave*
    InsertLeave			When leaving Insert mode.  Also when using
    				CTRL-O |i_CTRL-O|.  But not for |i_CTRL-C|.

    							*MenuPopup*
    MenuPopup			Just before showing the popup menu (under the
    				right mouse button).  Useful for adjusting the
    				menu for what is under the cursor or mouse
    				pointer.
    				The pattern is matched against a single
    				character representing the mode:
    					n	Normal
    					v	Visual
    					o	Operator-pending
    					i	Insert
    					c	Command line

    							*OptionSet*
    OptionSet			After setting an option.  The pattern is
    				matched against the long option name.
    				The |v:option_old| variable indicates the
    				old option value, |v:option_new| variable
    				indicates the newly set value, the
    				|v:option_type| variable indicates whether
    				it's global or local scoped and |<amatch>|
    				indicates what option has been set.

    				Is not triggered on startup and for the 'key'
    				option for obvious reasons.

    				Usage example: Check for the existence of the
    				directory in the 'backupdir' and 'undodir'
    				options, create the directory if it doesn't
    				exist yet.

    				Note: It's a bad idea to reset an option
    				during this autocommand, this may break a
    				plugin. You can always use `:noa` to prevent
    				triggering this autocommand.

    							*QuickFixCmdPre*
    QuickFixCmdPre			Before a quickfix command is run (|:make|,
    				|:lmake|, |:grep|, |:lgrep|, |:grepadd|,
    				|:lgrepadd|, |:vimgrep|, |:lvimgrep|,
    				|:vimgrepadd|, |:lvimgrepadd|, |:cscope|,
    				|:cfile|, |:cgetfile|, |:caddfile|, |:lfile|,
    				|:lgetfile|, |:laddfile|, |:helpgrep|,
    				|:lhelpgrep|, |:cexpr|, |:cgetexpr|,
    				|:caddexpr|, |:cbuffer|, |:cgetbuffer|,
    				|:caddbuffer|).
    				The pattern is matched against the command
    				being run.  When |:grep| is used but 'grepprg'
    				is set to "internal" it still matches "grep".
    				This command cannot be used to set the
    				'makeprg' and 'grepprg' variables.
    				If this command causes an error, the quickfix
    				command is not executed.

    							*QuickFixCmdPost*
    QuickFixCmdPost			Like QuickFixCmdPre, but after a quickfix
    				command is run, before jumping to the first
    				location. For |:cfile| and |:lfile| commands
    				it is run after error file is read and before
    				moving to the first error.
    				See |QuickFixCmdPost-example|.

    							*QuitPre*
    QuitPre				When using `:quit`, `:wq` or `:qall`, before
    				deciding whether it closes the current window
    				or quits Vim.  Can be used to close any
    				non-essential window if the current window is
    				the last ordinary window.
    				Also see |ExitPre|.

    							*RemoteReply*
    RemoteReply			When a reply from a Vim that functions as
    				server was received |server2client()|.  The
    				pattern is matched against the {serverid}.
    				<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.

    							*SessionLoadPost*
    SessionLoadPost			After loading the session file created using
    				the |:mksession| command.

    							*ShellCmdPost*
    ShellCmdPost			After executing a shell command with |:!cmd|,
    				|:shell|, |:make| and |:grep|.  Can be used to
    				check for any changed files.

    							*ShellFilterPost*
    ShellFilterPost			After executing a shell command with
    				":{range}!cmd", ":w !cmd" or ":r !cmd".
    				Can be used to check for any changed files.

    							*SourcePre*
    SourcePre			Before sourcing a Vim script. |:source|
    				<afile> is the name of the file being sourced.

    							*SourceCmd*
    SourceCmd			When sourcing a Vim script. |:source|
    				<afile> is the name of the file being sourced.
    				The autocommand must source this file.
    				|Cmd-event|

    							*SpellFileMissing*
    SpellFileMissing		When trying to load a spell checking file and
    				it can't be found.  The pattern is matched
    				against the language.  <amatch> is the
    				language, 'encoding' also matters.  See
    				|spell-SpellFileMissing|.

    							*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 |--|.

    							*StdinReadPre*
    StdinReadPre			Before reading from stdin into the buffer.
    				Only used when the "-" argument was used when
    				Vim was started |--|.

    							*SwapExists*
    SwapExists			Detected an existing swap file when starting
    				to edit a file.  Only when it is possible to
    				select a way to handle the situation, when Vim
    				would ask the user what to do.
    				The |v:swapname| variable holds the name of
    				the swap file found, <afile> the file being
    				edited.  |v:swapcommand| may contain a command
    				to be executed in the opened file.
    				The commands should set the |v:swapchoice|
    				variable to a string with one character to
    				tell Vim what should be done next:
    					'o'	open read-only
    					'e'	edit the file anyway
    					'r'	recover
    					'd'	delete the swap file
    					'q'	quit, don't edit the file
    					'a'	abort, like hitting CTRL-C
    				When set to an empty string the user will be
    				asked, as if there was no SwapExists autocmd.

    							*E812*
    				It is not allowed to change to another buffer,
    				change a buffer name or change directory
    				here.
    				{only available with the +eval feature}

    							*Syntax*
    Syntax				When the 'syntax' option has been set.  The
    				pattern is matched against the syntax name.
    				<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|.

    							*TabClosed*
    TabClosed			After closing a tab page.

    							*TabEnter*
    TabEnter			Just after entering a tab page. |tab-page|
    				After triggering the WinEnter and before
    				triggering the BufEnter event.

    							*TabLeave*
    TabLeave			Just before leaving a tab page. |tab-page|
    				A WinLeave event will have been triggered
    				first.

    							*TabNew*
    TabNew				When a tab page was created. |tab-page|
    				A WinEnter event will have been triggered
    				first, TabEnter follows.

    							*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.

    							*TerminalOpen*
    TerminalOpen			Just after a terminal buffer was created, with
    				`:terminal` or |term_start()|. This event is
    				triggered even if the buffer is created
    				without a window, with the ++hidden option.

    							*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.  Note that this event may be
    				triggered halfway executing another event,
    				especially if file I/O, a shell command or
    				anything else that takes time is involved.

    							*TextChanged*
    TextChanged			After a change was made to the text in the
    				current buffer in Normal mode.  That is when
    				|b:changedtick| has changed.
    				Not triggered when there is typeahead or when
    				an operator is pending.
    				Careful: This is triggered very often, don't
    				do anything that the user does not expect or
    				that is slow.

    							*TextChangedI*
    TextChangedI			After a change was made to the text in the
    				current buffer in Insert mode.
    				Not triggered when the popup menu is visible.
    				Otherwise the same as TextChanged.

    							*TextChangedP*
    TextChangedP			After a change was made to the text in the
    				current buffer in Insert mode, only when the
    				popup menu is visible.  Otherwise the same as
    				TextChanged.

    							*TextYankPost*
    TextYankPost			After text has been yanked or deleted in the
    				current buffer.  The following values of
    				|v:event| can be used to determine the operation
    				that triggered this autocmd:
    				   operator    	The operation performed.
    				   regcontents 	Text that was stored in the
    						register, as a list of lines,
    						like with:
    						getreg(r, 1, 1)
     				   regname	Name of the |register| or
    						empty string for the unnamed
    						register.
    				   regtype	Type of the register, see
    						|getregtype()|.
    				Not triggered when |quote_| is used nor when
    				called recursively.
    				It is not allowed to change the buffer text,
    				see |textlock|.
    				{only when compiled with the +eval feature}

    							*User*
    User				Never executed automatically.  To be used for
    				autocommands that are only executed with
    				":doautocmd".
    				Note that when `:doautocmd User MyEvent` is
    				used while there are no matching autocommands,
    				you will get an error.  If you don't want
    				that, define a dummy autocommand yourself.

    							*UserGettingBored*
    UserGettingBored		When the user presses the same key 42 times.
    				Just kidding! :-)

    							*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.
    				Just before this event is triggered the
    				|v:vim_did_enter| variable is set, so that you
    				can do:
    				   if v:vim_did_enter
    				     call s:init()
    				   else
     	  			     au VimEnter * call s:init()
    				   endif

     							*VimLeave*
    VimLeave			Before exiting Vim, just after writing the
    				.viminfo file.  Executed only once, like
    				VimLeavePre.
    				To detect an abnormal exit use |v:dying|.
    				When v:dying is 2 or more this event is not
    				triggered.

    							*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|.
    				When v:dying is 2 or more this event is not
    				triggered.

    							*VimResized*
    VimResized			After the Vim window was resized, thus 'lines'
    				and/or 'columns' changed.  Not when starting
    				up though.

    							*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: For split and tabpage commands the
    				WinEnter event is triggered after the split
    				or tab command but before the file 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.

    							*WinNew*
    WinNew				When a new window was created.  Not done for
    				the first window, when Vim has just started.
    				Before a WinEnter event.

    ==============================================================================

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

    The {pat} argument can be a comma separated list.  This works as if the
    command was given with each pattern separately.  Thus this command:
    	:autocmd BufRead *.txt,*.info set et
    Is equivalent to:
    	:autocmd BufRead *.txt set et
    	:autocmd BufRead *.info set et

    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 both the
       short file name (as you typed it) and the full file name (after expanding
       it to a full path and resolving symbolic links).

    The special pattern <buffer> or <buffer=N> is used for buffer-local
    autocommands |autocmd-buflocal|.  This pattern is not matched against the name
    of a buffer.

    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 if 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; Unusual: includes path
    		separators
    	?	matches any single character
    	\?	matches a '?'
    	.	matches a '.'
    	~	matches a '~'
    	,	separates patterns
    	\,	matches a ','
    	{ }	like \( \) in a |pattern|
    	,	inside { }: like \| in a |pattern||||
    	\}	literal }
    	\{	literal {
    	\\\{n,m\}  like \{n,m} 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.

    It is possible to use |pattern| items, but they may not work as expected,
    because of the translation done for the above.

    							*autocmd-changes*
    Matching with the pattern is done when an event is triggered.  Changing the
    buffer name in one of the autocommands, or even deleting the buffer, does not
    change which autocommands will be executed.  Example:

    	au BufEnter *.foo  bdel
    	au BufEnter *.foo  set modified

    This will delete the current buffer and then set 'modified' in what has become
    the current buffer instead.  Vim doesn't take into account that "*.foo"
    doesn't match with that buffer name.  It matches "*.foo" with the name of the
    buffer at the moment the event was triggered.

    However, buffer-local autocommands will not be executed for a buffer that has
    been wiped out with |:bwipe|.  After deleting the buffer with |:bdel| the
    buffer actually still exists (it becomes unlisted), thus the autocommands are
    still executed.

    ==============================================================================

    7. Buffer-local autocommands	*autocmd-buflocal* *autocmd-buffer-local*

    					*<buffer=N>* *<buffer=abuf>* *E680*

    Buffer-local autocommands are attached to a specific buffer.  They are useful
    if the buffer does not have a name and when the name does not match a specific
    pattern.  But it also means they must be explicitly added to each buffer.

    Instead of a pattern buffer-local autocommands use one of these forms:
    	<buffer>	current buffer
    	<buffer=99>	buffer number 99
    	<buffer=abuf>	using <abuf> (only when executing autocommands)
    			|<abuf>|

    Examples:
        :au CursorHold <buffer>  echo 'hold'
        :au CursorHold <buffer=33>  echo 'hold'
        :au BufNewFile * au CursorHold <buffer=abuf>  echo 'hold'

    All the commands for autocommands also work with buffer-local autocommands,
    simply use the special string instead of the pattern.  Examples:
        :au! * <buffer>		     " remove buffer-local autocommands for
    				     " current buffer
        :au! * <buffer=33>		     " remove buffer-local autocommands for
    				     " buffer #33
        :bufdo :au! CursorHold <buffer>  " remove autocmd for given event for all
    				     " buffers
        :au * <buffer>		     " list buffer-local autocommands for
    				     " current buffer

    Note that when an autocommand is defined for the current buffer, it is stored
    with the buffer number.  Thus it uses the form "<buffer=12>", where 12 is the
    number of the current buffer.  You will see this when listing autocommands,
    for example.

    To test for presence of buffer-local autocommands use the |exists()| function
    as follows:
        :if exists("#CursorHold#<buffer=12>") | ... | endif
        :if exists("#CursorHold#<buffer>") | ... | endif    " for current buffer

    When a buffer is wiped out its buffer-local autocommands are also gone, of
    course.  Note that when deleting a buffer, e.g., with ":bdel", it is only
    unlisted, the autocommands are still present.  In order to see the removal of
    buffer-local autocommands:
        :set verbose=6

    It is not possible to define buffer-local autocommands for a non-existent
    buffer.

    ==============================================================================

    8. Groups						*autocmd-groups*

    Autocommands can be put together in a group.  This is useful for removing or
    executing a group of autocommands.  For example, all the autocommands for
    syntax highlighting are put in the "highlight" group, to be able to execute
    ":doautoall highlight BufRead" when the GUI starts.

    When no specific group is selected, Vim uses the default group.  The default
    group does not have a name.  You cannot execute the autocommands from the
    default group separately; you can execute them only by executing autocommands
    for all groups.

    Normally, when executing autocommands automatically, Vim uses the autocommands
    for all groups.  The group only matters when executing autocommands with
    ":doautocmd" or ":doautoall", or when defining or deleting autocommands.

    The group name can contain any characters except white space.  The group name
    "end" is reserved (also in uppercase).

    The group name is case sensitive.  Note that this is different from the event
    name!

    							*:aug* *:augroup*
    :aug[roup] {name}		Define the autocmd group name for the
    				following ":autocmd" commands.  The name "end"
    				or "END" selects the default group.
    				To avoid confusion, the name should be
    				different from existing {event} names, as this
    				most likely will not do what you intended.

    					*:augroup-delete* *E367* *W19* *E936*
    :aug[roup]! {name}		Delete the autocmd group {name}.  Don't use
    				this if there is still an autocommand using
    				this group!  You will get a warning if doing
    				it anyway. when the group is the current group
    				you will get error E936.

    To enter autocommands for a specific group, use this method:
    1. Select the group with ":augroup {name}".
    2. Delete any old autocommands with ":au!".
    3. Define the autocommands.
    4. Go back to the default group with "augroup END".

    Example:
    	:augroup uncompress
    	:  au!
    	:  au BufEnter *.gz	%!gunzip
    	:augroup END

    This prevents having the autocommands defined twice (e.g., after sourcing the
    .vimrc file again).

    ==============================================================================

    9. Executing autocommands				*autocmd-execute*

    Vim can also execute Autocommands non-automatically.  This is useful if you
    have changed autocommands, or when Vim has executed the wrong autocommands
    (e.g., the file pattern match was wrong).

    Note that the 'eventignore' option applies here too.  Events listed in this
    option will not cause any commands to be executed.

    					*:do* *:doau* *:doautocmd* *E217*
    :do[autocmd] [<nomodeline>] [group] {event} [fname]
    			Apply the autocommands matching [fname] (default:
    			current file name) for {event} to the current buffer.
    			You can use this when the current file name does not
    			match the right pattern, after changing settings, or
    			to execute autocommands for a certain event.
    			It's possible to use this inside an autocommand too,
    			so you can base the autocommands for one extension on
    			another extension.  Example:
    				:au BufEnter *.cpp so ~/.vimrc_cpp
    				:au BufEnter *.cpp doau BufEnter x.c
     			Be careful to avoid endless loops.  See
    			|autocmd-nested|.

    			When the [group] argument is not given, Vim executes
    			the autocommands for all groups.  When the [group]
    			argument is included, Vim executes only the matching
    			autocommands for that group.  Note: if you use an
    			undefined group name, Vim gives you an error message.

    							*<nomodeline>*
    			After applying the autocommands the modelines are
    			processed, so that their settings overrule the
    			settings from autocommands, like what happens when
    			editing a file. This is skipped when the <nomodeline>
    			argument is present. You probably want to use
    			<nomodeline> for events that are not used when loading
    			a buffer, such as |User|.
    			Processing modelines is also skipped when no
    			matching autocommands were executed.

    						*:doautoa* *:doautoall*
    :doautoa[ll] [<nomodeline>] [group] {event} [fname]
    			Like ":doautocmd", but apply the autocommands to each
    			loaded buffer.  Note that [fname] is used to select
    			the autocommands, not the buffers to which they are
    			applied.
    			Careful: Don't use this for autocommands that delete a
    			buffer, change to another buffer or change the
    			contents of a buffer; the result is unpredictable.
    			This command is intended for autocommands that set
    			options, change highlighting, and things like that.

    ==============================================================================

    10. Using autocommands					*autocmd-use*

    For WRITING FILES there are four possible sets of events.  Vim uses only one
    of these sets for a write command:

    BufWriteCmd	BufWritePre	BufWritePost	writing the whole buffer
    		FilterWritePre	FilterWritePost	writing to filter temp file
    FileAppendCmd	FileAppendPre	FileAppendPost	appending to a file
    FileWriteCmd	FileWritePre	FileWritePost	any other file write

    When there is a matching "*Cmd" autocommand, it is assumed it will do the
    writing.  No further writing is done and the other events are not triggered.
    |Cmd-event|

    Note that the *WritePost commands should undo any changes to the buffer that
    were caused by the *WritePre commands; otherwise, writing the file will have
    the side effect of changing the buffer.

    Before executing the autocommands, the buffer from which the lines are to be
    written temporarily becomes the current buffer.  Unless the autocommands
    change the current buffer or delete the previously current buffer, the
    previously current buffer is made the current buffer again.

    The *WritePre and *AppendPre autocommands must not delete the buffer from
    which the lines are to be written.

    The '[ and '] marks have a special position:
    - Before the *ReadPre event the '[ mark is set to the line just above where
      the new lines will be inserted.
    - Before the *ReadPost event the '[ mark is set to the first line that was
      just read, the '] mark to the last line.
    - Before executing the *WriteCmd, *WritePre and *AppendPre autocommands the '[
      mark is set to the first line that will be written, the '] mark to the last
      line.
    Careful: '[ and '] change when using commands that change the buffer.

    In commands which expect a file name, you can use "<afile>" for the file name
    that is being read |:<afile>| (you can also use "%" for the current file
    name).  "<abuf>" can be used for the buffer number of the currently effective
    buffer.  This also works for buffers that doesn't have a name.  But it doesn't
    work for files without a buffer (e.g., with ":r file").

    							*gzip-example*
    Examples for reading and writing compressed files:
      :augroup gzip
      :  autocmd!
      :  autocmd BufReadPre,FileReadPre	*.gz set bin
      :  autocmd BufReadPost,FileReadPost	*.gz '[,']!gunzip
      :  autocmd BufReadPost,FileReadPost	*.gz set nobin
      :  autocmd BufReadPost,FileReadPost	*.gz execute ":doautocmd BufReadPost " . expand("%:r")
      :  autocmd BufWritePost,FileWritePost	*.gz !mv <afile> <afile>:r
      :  autocmd BufWritePost,FileWritePost	*.gz !gzip <afile>:r

      :  autocmd FileAppendPre		*.gz !gunzip <afile>
      :  autocmd FileAppendPre		*.gz !mv <afile>:r <afile>
      :  autocmd FileAppendPost		*.gz !mv <afile> <afile>:r
      :  autocmd FileAppendPost		*.gz !gzip <afile>:r
      :augroup END

    The "gzip" group is used to be able to delete any existing autocommands with
    ":autocmd!", for when the file is sourced twice.

    ("<afile>:r" is the file name without the extension, see |:_%:|)

    The commands executed for the BufNewFile, BufRead/BufReadPost, BufWritePost,
    FileAppendPost and VimLeave events do not set or reset the changed flag of the
    buffer.  When you decompress the buffer with the BufReadPost autocommands, you
    can still exit with ":q".  When you use ":undo" in BufWritePost to undo the
    changes made by BufWritePre commands, you can still do ":q" (this also makes
    "ZZ" work).  If you do want the buffer to be marked as modified, set the
    'modified' option.

    To execute Normal mode commands from an autocommand, use the ":normal"
    command.  Use with care!  If the Normal mode command is not finished, the user
    needs to type characters (e.g., after ":normal m" you need to type a mark
    name).

    If you want the buffer to be unmodified after changing it, reset the
    'modified' option.  This makes it possible to exit the buffer with ":q"
    instead of ":q!".

    							*autocmd-nested* *E218*
    By default, autocommands do not nest.  If you use ":e" or ":w" in an
    autocommand, Vim does not execute the BufRead and BufWrite autocommands for
    those commands.  If you do want this, use the "nested" flag for those commands
    in which you want nesting.  For example:
      :autocmd FileChangedShell *.c nested e!
    The nesting is limited to 10 levels to get out of recursive loops.

    It's possible to use the ":au" command in an autocommand.  This can be a
    self-modifying command!  This can be useful for an autocommand that should
    execute only once.

    If you want to skip autocommands for one command, use the |:noautocmd| command
    modifier or the 'eventignore' option.

    Note: When reading a file (with ":read file" or with a filter command) and the
    last line in the file does not have an <EOL>, Vim remembers this.  At the next
    write (with ":write file" or with a filter command), if the same line is
    written again as the last line in a file AND 'binary' is set, Vim does not
    supply an <EOL>.  This makes a filter command on the just read lines write the
    same file as was read, and makes a write command on just filtered lines write
    the same file as was read from the filter.  For example, another way to write
    a compressed file:

      :autocmd FileWritePre *.gz   set bin|'[,']!gzip
      :autocmd FileWritePost *.gz  undo|set nobin

    							*autocommand-pattern*
    You can specify multiple patterns, separated by commas.  Here are some
    examples:

      :autocmd BufRead   *		set tw=79 nocin ic infercase fo=2croq
      :autocmd BufRead   .letter	set tw=72 fo=2tcrq
      :autocmd BufEnter  .letter	set dict=/usr/lib/dict/words
      :autocmd BufLeave  .letter	set dict=
      :autocmd BufRead,BufNewFile   *.c,*.h	set tw=0 cin noic
      :autocmd BufEnter  *.c,*.h	abbr FOR for (i = 0; i < 3; ++i)<CR>{<CR>}<Esc>O
      :autocmd BufLeave  *.c,*.h	unabbr FOR

    For makefiles (makefile, Makefile, imakefile, makefile.unix, etc.):

      :autocmd BufEnter  ?akefile*	set include=^s\=include
      :autocmd BufLeave  ?akefile*	set include&

    To always start editing C files at the first function:

      :autocmd BufRead   *.c,*.h	1;/^{

    Without the "1;" above, the search would start from wherever the file was
    entered, rather than from the start of the file.

    						*skeleton* *template*
    To read a skeleton (template) file when opening a new file:

      :autocmd BufNewFile  *.c	0r ~/vim/skeleton.c
      :autocmd BufNewFile  *.h	0r ~/vim/skeleton.h
      :autocmd BufNewFile  *.java	0r ~/vim/skeleton.java

    To insert the current date and time in a *.html file when writing it:

      :autocmd BufWritePre,FileWritePre *.html   ks|call LastMod()|'s
      :fun LastMod()
      :  if line("$") > 20
      :    let l = 20
      :  else
      :    let l = line("$")
      :  endif
      :  exe "1," . l . "g/Last modified: /s/Last modified: .*/Last modified: " .
      :  \ strftime("%Y %b %d")
      :endfun

    You need to have a line "Last modified: <date time>" in the first 20 lines
    of the file for this to work.  Vim replaces <date time> (and anything in the
    same line after it) with the current date and time.  Explanation:
    	ks		mark current position with mark 's'
    	call LastMod()  call the LastMod() function to do the work
    	's		return the cursor to the old position
    The LastMod() function checks if the file is shorter than 20 lines, and then
    uses the ":g" command to find lines that contain "Last modified: ".  For those
    lines the ":s" command is executed to replace the existing date with the
    current one.  The ":execute" command is used to be able to use an expression
    for the ":g" and ":s" commands.  The date is obtained with the strftime()
    function.  You can change its argument to get another date string.

    When entering :autocmd on the command-line, completion of events and command
    names may be done (with <Tab>, CTRL-D, etc.) where appropriate.

    Vim executes all matching autocommands in the order that you specify them.
    It is recommended that your first autocommand be used for all files by using
    "*" as the file pattern.  This means that you can define defaults you like
    here for any settings, and if there is another matching autocommand it will
    override these.  But if there is no other matching autocommand, then at least
    your default settings are recovered (if entering this file from another for
    which autocommands did match).  Note that "*" will also match files starting
    with ".", unlike Unix shells.

    						    *autocmd-searchpat*
    Autocommands do not change the current search patterns.  Vim saves the current
    search patterns before executing autocommands then restores them after the
    autocommands finish.  This means that autocommands do not affect the strings
    highlighted with the 'hlsearch' option.  Within autocommands, you can still
    use search patterns normally, e.g., with the "n" command.
    If you want an autocommand to set the search pattern, such that it is used
    after the autocommand finishes, use the ":let @/ =" command.
    The search-highlighting cannot be switched off with ":nohlsearch" in an
    autocommand.  Use the 'h' flag in the 'viminfo' option to disable search-
    highlighting when starting Vim.

    							*Cmd-event*
    When using one of the "*Cmd" events, the matching autocommands are expected to
    do the file reading, writing or sourcing.  This can be used when working with
    a special kind of file, for example on a remote system.
    CAREFUL: If you use these events in a wrong way, it may have the effect of
    making it impossible to read or write the matching files!  Make sure you test
    your autocommands properly.  Best is to use a pattern that will never match a
     normal file name, for example "ftp://*".

    When defining a BufReadCmd it will be difficult for Vim to recover a crashed
    editing session.  When recovering from the original file, Vim reads only those
    parts of a file that are not found in the swap file.  Since that is not
    possible with a BufReadCmd, use the |:preserve| command to make sure the
    original file isn't needed for recovery.  You might want to do this only when
    you expect the file to be modified.

    For file read and write commands the |v:cmdarg| variable holds the "++enc="
    and "++ff=" argument that are effective.  These should be used for the command
    that reads/writes the file.  The |v:cmdbang| variable is one when "!" was
    used, zero otherwise.

    See the $VIMRUNTIME/plugin/netrwPlugin.vim for examples.

    ==============================================================================

    11. Disabling autocommands				*autocmd-disable*

    To disable autocommands for some time use the 'eventignore' option.  Note that
    this may cause unexpected behavior, make sure you restore 'eventignore'
    afterwards, using a |:try| block with |:finally|.

    							*:noautocmd* *:noa*
    To disable autocommands for just one command use the ":noautocmd" command
    modifier.  This will set 'eventignore' to "all" for the duration of the
    following command.  Example:

    	:noautocmd w fname.gz

    This will write the file without triggering the autocommands defined by the
    gzip plugin.

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