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autocmd.txt   Nvim


                  VIM REFERENCE MANUAL    by Bram Moolenaar


Automatic commands                                      autocmd autocommand

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

                                      Type gO to see the table of contents.

==============================================================================
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 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} {aupat} [++once] [++nested] {cmd}
                        Add {cmd} to the list of commands that Vim will
                        execute automatically on {event} for a file matching
                        {aupat} autocmd-pattern.
                        Note: A quote character is seen as argument to the
                        :autocmd and won't start a comment.
                        Nvim always adds {cmd} after existing autocommands so
                        they execute in the order in which they were defined.
                        See autocmd-nested for [++nested].
                                                        autocmd-once
                        If [++once] is supplied the command is executed once,
                        then removed ("one shot").

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 where the pattern is expected.  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

                                                       autocmd-expand
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} {aupat} [++once] [++nested] {cmd}
                        Remove all autocommands associated with {event} and
                        {aupat}, and add the command {cmd}.
                        See autocmd-once for [++once].
                        See autocmd-nested for [++nested].

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

:au[tocmd]! [group] * {aupat}
                        Remove all autocommands associated with {aupat} 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} {aupat}
                        Show the autocommands associated with {event} and
                        {aupat}.

:au[tocmd] [group] * {aupat}
                        Show the autocommands associated with {aupat} 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.

                                                        events {event}
Nvim recognizes the following events.  Names are case-insensitive.

                                                        BufAdd
BufAdd                          Just after creating a new buffer which is
                                added to the buffer list, or adding a buffer
                                to the buffer list, a buffer in the buffer
                                list was renamed.
                                Not triggered for the initial buffers created
                                during startup.
                                Before BufEnter.
                                NOTE: 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: Current buffer "%" may be different from
                                the buffer being deleted "<afile>" and "<abuf>".
                                Do not change to another buffer.
                                                        BufEnter
BufEnter                        After entering a buffer.  Useful for setting
                                options for a file type.  Also executed when
                                starting to edit a buffer.
                                After BufAdd.
                                After BufReadPost.
                                                        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                       Before a buffer becomes hidden: 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: 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.
                                                        BufModifiedSet
BufModifiedSet                  After the 'modified' value of a buffer has
                                been changed.
                                                        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: 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
                                processing modelines.  See BufWinEnter to do
                                something after processing modelines.
                                Also triggered:
                                - when writing an unnamed buffer in a way that
                                  the buffer gets a name
                                - after successfully recovering a file
                                - for the "filetypedetect" group when
                                  executing ":filetype detect"
                                Not triggered:
                                - for the `:read file` command
                                - when the file doesn't exist
                                                        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, when the text in 
                                the buffer is going to be freed.
                                After BufWritePost.
                                Before BufDelete.
                                Triggers for all loaded buffers when Vim is
                                going to exit.
                                NOTE: Current buffer "%" may be different from
                                the buffer being unloaded "<afile>".
                                Do not switch buffers or windows!
                                Not triggered when exiting and v:dying is 2 or
                                more.
                                                        BufWinEnter
BufWinEnter                     After a buffer is displayed in a window.  This
                                may be when the buffer is loaded (after
                                processing modelines) or when a hidden buffer
                                is displayed (and is no longer hidden).

                                Not triggered for :split without arguments,
                                since the buffer does not change, or :split
                                with a file already open in a window.
                                Triggered for ":split" with the name of the
                                current buffer, since it reloads that buffer.
                                                        BufWinLeave
BufWinLeave                     Before a buffer is removed from a window.
                                Not when it's still visible in another window.
                                Also triggered when exiting.
                                Before BufUnload, BufHidden.
                                NOTE: Current buffer "%" may be different from
                                the buffer being unloaded "<afile>".
                                Not triggered when exiting and v:dying is 2 or
                                more.
                                                        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: Current buffer "%" may be different from
                                the buffer being deleted "<afile>".
                                Do not change to another buffer.
                                                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).
                                                        ChanInfo
ChanInfo                        State of channel changed, for instance the
                                client of a RPC channel described itself.
                                Sets these v:event keys:
                                    info
                                See nvim_get_chan_info() for the format of
                                the info Dictionary.
                                                        ChanOpen
ChanOpen                        Just after a channel was opened.
                                Sets these v:event keys:
                                    info
                                See nvim_get_chan_info() for the format of
                                the info Dictionary.
                                                        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> expand to the command name.
                                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 inside
                                command line.  Be careful not to mess up the
                                command line, it may cause Vim to lock up.
                                <afile> expands to the cmdline-char.
                                                        CmdlineEnter
CmdlineEnter                    After entering the command-line (including
                                non-interactive use of ":" in a mapping: use
                                <Cmd> instead to avoid this).
                                <afile> expands to the cmdline-char.
                                Sets these v:event keys:
                                    cmdlevel
                                    cmdtype
                                                        CmdlineLeave
CmdlineLeave                    Before leaving the command-line (including
                                non-interactive use of ":" in a mapping: use
                                <Cmd> instead to avoid this).
                                <afile> expands to the cmdline-char.
                                Sets these v:event keys:
                                    abort (mutable)
                                    cmdlevel
                                    cmdtype
                                Note: abort can only be changed from false
                                to true: cannot execute an already aborted
                                cmdline by changing it to false.
                                                        CmdwinEnter
CmdwinEnter                     After entering the command-line window.
                                Useful for setting options specifically for
                                this special type of window.
                                <afile> expands 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.
                                <afile> expands to a single character,
                                indicating the type of command-line.
                                cmdwin-char
                                                        ColorScheme
ColorScheme                     After loading a color scheme. :colorscheme
                                Not triggered if the color scheme is not
                                found.
                                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.

CompleteChanged                                         CompleteChanged
                                After each time the Insert mode completion
                                menu changed.  Not fired on popup menu hide,
                                use CompleteDonePre or CompleteDone for
                                that.

                                Sets these v:event keys:
                                    completed_item      See complete-items.
                                    height              nr of items visible
                                    width               screen cells
                                    row                 top screen row
                                    col                 leftmost screen column
                                    size                total nr of items
                                    scrollbar           TRUE if visible

                                Non-recursive (event cannot trigger itself).
                                Cannot change the text. textlock

                                The size and position of the popup are also
                                available by calling pum_getpos().

                                                        CompleteDonePre
CompleteDonePre                 After Insert mode completion is done.  Either
                                when something was completed or abandoning
                                completion. ins-completion
                                complete_info() can be used, the info is
                                cleared after triggering CompleteDonePre.
                                The v:completed_item variable contains
                                information about the completed item.

                                                        CompleteDone
CompleteDone                    After Insert mode completion is done.  Either
                                when something was completed or abandoning
                                completion. ins-completion
                                complete_info() cannot be used, the info is
                                cleared before triggering CompleteDone.  Use
                                CompleteDonePre if you need it.
                                v:completed_item gives the completed item.

                                                        CursorHold
CursorHold                      When the user doesn't press a key for the time
                                specified with 'updatetime'.  Not 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

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

                                                        CursorMoved
CursorMoved                     After the cursor was moved in Normal or Visual
                                mode or to another window.  Also when the text
                                of the cursor line has been changed, e.g. with
                                "x", "rx" or "p".
                                Not always triggered when there is typeahead,
                                while executing commands in a script file, or
                                when an operator is pending. Always triggered
                                when moving to another window.
                                For an example see match-parens.
                                Note: Cannot be skipped with :noautocmd.
                                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.
                                                        DiffUpdated
DiffUpdated                     After diffs have been updated.  Depending on
                                what kind of diff is being used (internal or
                                external) this can be triggered on every
                                change or when doing :diffupdate.
                                                        DirChanged
DirChanged                      After the current-directory was changed.
                                The pattern can be:
                                        "window"  to trigger on :lcd
                                        "tabpage" to trigger on :tcd
                                        "global"  to trigger on :cd
                                        "auto"    to trigger on 'autochdir'.
                                Sets these v:event keys:
                                    cwd:            current working directory
                                    scope:          "global", "tabpage", "window"
                                    changed_window: v:true if we fired the event
                                                    switching window (or tab)
                                <afile> is set to the new directory name.
                                Non-recursive (event cannot trigger itself).
                                                        DirChangedPre
DirChangedPre                   When the current-directory is going to be
                                changed, as with DirChanged.
                                The pattern is like with DirChanged.
                                Sets these v:event keys:
                                    directory:      new working directory
                                    scope:          "global", "tabpage", "window"
                                    changed_window: v:true if we fired the event
                                                    switching window (or tab)
                                <afile> is set to the new directory name.
                                Non-recursive (event cannot trigger itself).
                                                        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.  Exiting may still be
                                cancelled if there is a modified buffer that
                                isn't automatically saved, use VimLeavePre
                                for really exiting.
                                See also QuitPre, WinClosed.
                                                        FileAppendCmd
FileAppendCmd                   Before appending to a file.  Should do the
                                appending to the file.  Use the '[ and ']
                                marks for the range of lines. Cmd-event
                                                        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 checkout the file from
                                a source control system.  Not triggered when
                                the change was caused by an autocommand.
                                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
                                Cannot switch buffers.  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.
                                                        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
                                Triggered for each changed file, after:
                                - executing a shell command
                                - :checktime
                                - FocusGained 

                                Not used when 'autoread' is set and the buffer
                                was not changed.  If a FileChangedShell
                                autocommand exists the warning message and
                                prompt is not given.
                                v:fcs_reason indicates what happened. Set
                                v:fcs_choice to control what happens next.
                                NOTE: Current buffer "%" may be different from
                                the buffer that was changed "<afile>".
                                                        E246 E811
                                Cannot switch, jump to or delete buffers.
                                Non-recursive (event cannot trigger itself).
                                                        FileChangedShellPost
FileChangedShellPost            After handling a file that was changed outside
                                of Vim.  Can be used to update the statusline.
                                                        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> is the name of the file where this
                                option was set.  <amatch> is the new value of
                                'filetype'.
                                Cannot switch windows or buffers.
                                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 with an external diff (see
                                DiffUpdated for internal 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 with an external 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                     Nvim got focus.
                                                        FocusLost
FocusLost                       Nvim lost focus.  Also (potentially) when
                                a GUI 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.
                                                        UIEnter
UIEnter                         After a UI connects via nvim_ui_attach(), or
                                after builtin TUI is started, after VimEnter.
                                Sets these v:event keys:
                                    chan: 0 for builtin TUI
                                          1 for --embed
                                          channel-id of the UI otherwise
                                                        UILeave
UILeave                         After a UI disconnects from Nvim, or after
                                builtin TUI is stopped, after VimLeave.
                                Sets these v:event keys:
                                    chan: 0 for builtin TUI
                                          1 for --embed
                                          channel-id of the UI otherwise
                                                        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.

                                Cannot change the text. textlock
                                Not triggered when 'paste' is set.
                                                        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.
                                                        InsertLeavePre
InsertLeavePre                  Just before leaving Insert mode.  Also when
                                using CTRL-O i_CTRL-O.  Be careful not to
                                change mode or use :normal, it will likely
                                cause trouble.
                                                        InsertLeave
InsertLeave                     Just after 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 one or two
                                characters representing the mode:
                                        n       Normal
                                        v       Visual
                                        o       Operator-pending
                                        i       Insert
                                        c       Command line
                                        tl      Terminal
                                                        ModeChanged
ModeChanged                     After changing the mode. The pattern is
                                matched against 'old_mode:new_mode', for
                                example match against *:c to simulate
                                CmdlineEnter.
                                The following values of v:event are set:
                                        old_mode The mode before it changed.
                                        new_mode The new mode as also returned
                                                by mode() called with a
                                                non-zero argument.
                                When ModeChanged is triggered, old_mode will
                                have the value of new_mode when the event was
                                last triggered.
                                This will be triggered on every minor mode
                                change.
                                Usage example to use relative line numbers
                                when entering visual mode: 
                :au ModeChanged [vV\x16]*:* let &l:rnu = mode() =~# '^[vV\x16]'
                :au ModeChanged *:[vV\x16]* let &l:rnu = mode() =~# '^[vV\x16]'
                :au WinEnter,WinLeave * let &l:rnu = mode() =~# '^[vV\x16]'
                                                       OptionSet
OptionSet                       After setting an option (except during
                                startup).  The autocmd-pattern is matched
                                against the long option name.  <amatch>
                                indicates what option has been set.

                                v:option_type indicates whether it's global
                                or local scoped.
                                v:option_command indicates what type of
                                set/let command was used (follow the tag to
                                see the table).
                                v:option_new indicates the newly set value.
                                v:option_oldlocal has the old local value.
                                v:option_oldglobal has the old global value.
                                v:option_old indicates the old option value.

                                v:option_oldlocal is only set when :set
                                or :setlocal or a modeline was used to set
                                the option. Similarly v:option_oldglobal is
                                only set when :set or :setglobal was used.

                                Note that when setting a global-local string
                                option with :set, then v:option_old is the
                                old global value. However, for all other kinds
                                of options (local string options, global-local
                                number options, ...) it is the old local
                                value.

                                OptionSet 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: Do not reset the same option during this
                                autocommand, that may break plugins. You can
                                always use :noautocmd to prevent triggering
                                OptionSet.

                                Non-recursive: :set in the autocommand does
                                not trigger OptionSet again.

                                                        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.  For :wq the buffer is written
                                before QuitPre is triggered.  Can be used to
                                close any non-essential window if the current
                                window is the last ordinary window.
                                See also ExitPre, WinClosed.
                                                        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.
                                                        SearchWrapped
SearchWrapped                   After making a search with n or N if the
                                search wraps around the document back to
                                the start/finish respectively.
                                                        RecordingEnter
RecordingEnter                  When a macro starts recording.
                                The pattern is the current file name, and
                                reg_recording() is the current register that
                                is used.
                                                        RecordingLeave
RecordingLeave                  When a macro stops recording.
                                The pattern is the current file name, and
                                reg_recording() is the recorded
                                register.
                                reg_recorded() is only updated after this
                                event.
                                Sets these v:event keys:
                                    regcontents
                                    regname
                                                        SessionLoadPost
SessionLoadPost                 After loading the session file created using
                                the :mksession command.
                                                        ShellCmdPost
ShellCmdPost                    After executing a shell command with :!cmd,
                                :make and :grep.  Can be used to check for
                                any changed files.
                                For non-blocking shell commands, see
                                job-control.
                                                        Signal
Signal                          After Nvim receives a signal. The pattern is
                                matched against the signal name. Only
                                "SIGUSR1" and "SIGWINCH" are supported.  Example: 
                                    autocmd Signal SIGUSR1 call some#func()
                                                       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/lua file. :source
                                <afile> is the name of the file being sourced.
                                                        SourcePost
SourcePost                      After sourcing a vim/lua file. :source
                                <afile> is the name of the file being sourced.
                                Not triggered when sourcing was interrupted.
                                Also triggered after a SourceCmd autocommand
                                was triggered.
                                                        SourceCmd
SourceCmd                       When sourcing a vim/lua file. :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                   During startup, after reading from stdin into
                                the buffer, before executing modelines. --
                                                        StdinReadPre
StdinReadPre                    During startup, before reading from stdin into
                                the buffer. --
                                                        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
                                Cannot change to another buffer, change
                                the buffer name or change directory.
                                                        Syntax
Syntax                          When the 'syntax' option has been set.  The
                                pattern is matched against the syntax name.
                                <afile> expands to the name of the file where
                                this option was set. <amatch> expands to the
                                new value of 'syntax'.
                                See :syn-on.
                                                        TabEnter
TabEnter                        Just after entering a tab page. tab-page
                                After WinEnter.
                                Before BufEnter.
                                                        TabLeave
TabLeave                        Just before leaving a tab page. tab-page
                                After WinLeave.
                                                        TabNew
TabNew                          When creating a new tab page. tab-page
                                After WinEnter.
                                Before TabEnter.
                                                        TabNewEntered
TabNewEntered                   After entering a new tab page. tab-page
                                After BufEnter.
                                                        TabClosed
TabClosed                       After closing a tab page. <afile> expands to
                                the tab page number.
                                                        TermOpen
TermOpen                        When a terminal job is starting.  Can be
                                used to configure the terminal buffer.
                                                        TermEnter
TermEnter                       After entering Terminal-mode.
                                After TermOpen.
                                                        TermLeave
TermLeave                       After leaving Terminal-mode.
                                After TermClose.
                                                        TermClose
TermClose                       When a terminal job ends.
                                Sets these v:event keys:
                                    status
                                                        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.  May be triggered halfway
                                through another event (file I/O, a shell
                                command, or anything else that takes time).
                                                        TextChanged
TextChanged                     After a change was made to the text in the
                                current buffer in Normal mode.  That is after
                                b:changedtick has changed (also when that
                                happened before the TextChanged autocommand
                                was defined).
                                Not triggered when there is typeahead or when
                                an operator is pending.
                                Note: Cannot be skipped with :noautocmd.
                                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                    Just after a yank or deleting command, but not
                                if the black hole register quote_ is used nor
                                for setreg(). Pattern must be *.
                                Sets these v:event keys:
                                    inclusive
                                    operator
                                    regcontents
                                    regname
                                    regtype
                                    visual
                                The inclusive flag combined with the '[
                                and '] marks can be used to calculate the
                                precise region of the operation.

                                Non-recursive (event cannot trigger itself).
                                Cannot change the text. textlock
                                                        User
User                            Not executed automatically.  Use :doautocmd
                                to trigger this, typically for "custom events"
                                in a plugin.  Example: 
                                    :autocmd User MyPlugin echom 'got MyPlugin event'
                                    :doautocmd User MyPlugin
                                                       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
                                .shada file.  Executed only once, like
                                VimLeavePre.
                                Use v:dying to detect an abnormal exit.
                                Use v:exiting to get the exit code.
                                Not triggered if v:dying is 2 or more.
                                                        VimLeavePre
VimLeavePre                     Before exiting Vim, just before writing the
                                .shada 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()
                               Use v:dying to detect an abnormal exit.
                                Use v:exiting to get the exit code.
                                Not triggered if v:dying is 2 or more.
                                                        VimResized
VimResized                      After the Vim window was resized, thus 'lines'
                                and/or 'columns' changed.  Not when starting
                                up though.
                                                        VimResume
VimResume                       After Nvim resumes from suspend state.
                                                        VimSuspend
VimSuspend                      Before Nvim enters suspend state.
                                                        WinClosed
WinClosed                       After closing a window.  The pattern is
                                matched against the window-ID.  Both
                                <amatch> and <afile> are set to the window-ID.
                                After WinLeave.
                                Non-recursive (event cannot trigger itself).
                                See also ExitPre, QuitPre.
                                                        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.
                                Before WinClosed.
                                                        WinNew
WinNew                          When a new window was created.  Not done for
                                the first window, when Vim has just started.
                                Before WinEnter.

                                                        WinScrolled
WinScrolled                     After scrolling the content of a window or
                                resizing a window.
                                The pattern is matched against the
                                window-ID.  Both <amatch> and <afile> are
                                set to the window-ID.
                                Non-recursive (the event cannot trigger
                                itself).  However, if the command causes the
                                window to scroll or change size another
                                WinScrolled event will be triggered later.
                                Does not trigger when the command is added,
                                only after the first scroll or resize.

==============================================================================
6. Patterns                                     autocmd-pattern {aupat}

The {aupat} argument of :autocmd 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 {aupat} 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 ~/.config/nvim/init.vim   so <afile>
        :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
Windows). 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> <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).

                                                FileExplorer
There is one group that is recognized by Vim: FileExplorer.  If this group
exists Vim assumes that editing a directory is possible and will trigger a
plugin that lists the files in that directory.  This is used by the netrw
plugin.  This allows you to do: 
        browse edit

==============================================================================
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 :doaut :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 ~/.config/nvim/init_cpp.vim
                                :au BufEnter *.cpp doau BufEnter x.c
                       Be careful to avoid endless loops.  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.  Undefined group is an
                        error.
                                                        <nomodeline>
                        After applying the autocommands the modelines are
                        processed, so that their settings overrule the
                        settings from autocommands when editing a file. This
                        is skipped if <nomodeline> is specified. You probably
                        want to use <nomodeline> for events not used when
                        loading a buffer, such as User.
                        Modelines are 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.  The current buffer is done last.

                        Note that [fname] is used to select the autocommands,
                        not the buffers to which they are applied. Example: 
                                augroup mine
                                  autocmd!
                                  autocmd FileType * echo expand('<amatch>')
                                augroup END
                                doautoall mine FileType Loaded-Buffer
                       Sourcing this script, you'll see as many
                        "Loaded-Buffer" echoed as there are loaded buffers.

                        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 don'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.  For example, 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 'shada' 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.

Note that some autocommands are not triggered right away, but only later.
This specifically applies to CursorMoved and TextChanged.


 vim:tw=78:ts=8:noet:ft=help:norl:


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