runtime/doc/diff.txt - android_external_vim - Gitiles

 *diff.txt*      For Vim version 9.1.  Last change: 2025 Jun 20


 		  VIM REFERENCE MANUAL    by Bram Moolenaar


 				*diff* *vimdiff* *gvimdiff* *diff-mode*
 This file describes the |+diff| feature: Showing differences between two to
 eight versions of the same file.

 The basics are explained in section |08.7| of the user manual.

 1. Starting diff mode		|start-vimdiff|
 2. Viewing diffs		|view-diffs|
 3. Jumping to diffs		|jumpto-diffs|
 4. Copying diffs		|copy-diffs|
 5. Diff options			|diff-options|

 ==============================================================================
 1. Starting diff mode					*start-vimdiff*

 The easiest way to start editing in diff mode is with the "vimdiff" command.
 This starts Vim as usual, and additionally sets up for viewing the differences
 between the arguments. >

 	vimdiff file1 file2 [file3 [file4]]

 This is equivalent to: >

 	vim -d file1 file2 [file3 [file4]]

 You may also use "gvimdiff" or "vim -d -g".  The GUI is started then.
 You may also use "viewdiff" or "gviewdiff".  Vim starts in readonly mode then.
 "r" may be prepended for restricted mode (see |-Z|).

 The second and following arguments may also be a directory name.  Vim will
 then append the file name of the first argument to the directory name to find
 the file.

 By default an internal diff library will be used.  When 'diffopt' or
 'diffexpr' has been set an external "diff" command will be used.  This only
 works when such a diff program is available.

 Diffs are local to the current tab page |tab-page|.  You can't see diffs with
 a window in another tab page.  This does make it possible to have several
 diffs at the same time, each in their own tab page.

 What happens is that Vim opens a window for each of the files.  This is like
 using the |-O| argument.  This uses vertical splits.  If you prefer horizontal
 splits add the |-o| argument: >

 	vimdiff -o file1 file2 [file3 [file4]]

 If you always prefer horizontal splits include "horizontal" in 'diffopt'.

 In each of the edited files these options are set:

 	'diff'		on
 	'scrollbind'	on
 	'cursorbind'	on
 	'scrollopt'	includes "hor"
 	'wrap'		off, or leave as-is if 'diffopt' includes "followwrap"
 	'foldmethod'	"diff"
 	'foldcolumn'	value from 'diffopt', default is 2

 These options are set local to the window.  When editing another file they are
 reset to the global value.
 The options can still be overruled from a modeline when re-editing the file.
 However, 'foldmethod' and 'wrap' won't be set from a modeline when 'diff' is
 set.
 See `:diffoff` for an easy way to revert the options.

 The differences shown are actually the differences in the buffer.  Thus if you
 make changes after loading a file, these will be included in the displayed
 diffs.  You might have to do ":diffupdate" now and then, not all changes are
 immediately taken into account, especially when using an external diff command.

 In your .vimrc file you could do something special when Vim was started in
 diff mode.  You could use a construct like this: >

 	if &diff
 	   setup for diff mode
 	else
 	   setup for non-diff mode
 	endif

 While already in Vim you can start diff mode in three ways.

 							*E98*
 :diffs[plit] {filename}					*:diffs* *:diffsplit*
 		Open a new window on the file {filename}.  The options are set
 		as for "vimdiff" for the current and the newly opened window.
 		Also see 'diffexpr'.

 							*:difft* *:diffthis*
 :difft[his]	Make the current window part of the diff windows.  This sets
 		the options like for "vimdiff".

 :diffp[atch] {patchfile}			 *E816* *:diffp* *:diffpatch*
 		Use the current buffer, patch it with the diff found in
 		{patchfile} and open a buffer on the result.  The options are
 		set as for "vimdiff".
 		{patchfile} can be in any format that the "patch" program
 		understands or 'patchexpr' can handle.
 		Note that {patchfile} should only contain a diff for one file,
 		the current file.  If {patchfile} contains diffs for other
 		files as well, the results are unpredictable.  Vim changes
 		directory to /tmp to avoid files in the current directory
 		accidentally being patched.  But it may still result in
 		various ".rej" files to be created.  And when absolute path
 		names are present these files may get patched anyway.
 		Using the "patch" command is not allowed in |restricted-mode|.

 To make these commands use a vertical split, prepend |:vertical|.  Examples: >

 	:vert diffsplit main.c~
 	:vert diffpatch /tmp/diff

 If you always prefer a vertical split include "vertical" in 'diffopt'.

 							*E96*
 There can be up to eight buffers with 'diff' set.

 Since the option values are remembered with the buffer, you can edit another
 file for a moment and come back to the same file and be in diff mode again.

 							*:diffo* *:diffoff*
 :diffo[ff]	Switch off diff mode for the current window.  Resets related
 		options also when 'diff' was not set.

 :diffo[ff]!	Switch off diff mode for the current window and in all windows
 		in the current tab page where 'diff' is set.  Resetting
 		related options only happens in a window that has 'diff' set,
 		if the current window does not have 'diff' set then no options
 		in it are changed.
 		Hidden buffers are also removed from the list of diff'ed
 		buffers.

 The `:diffoff` command resets the relevant options to the values they had when
 using `:diffsplit`, `:diffpatch`, `:diffthis`. or starting Vim in diff mode.
 When using `:diffoff` twice the last saved values are restored.
 Otherwise they are set to their default value:

 	'diff'		off
 	'scrollbind'	off
 	'cursorbind'	off
 	'scrollopt'	without "hor"
 	'wrap'		on, or leave as-is if 'diffopt' includes "followwrap"
 	'foldmethod'	"manual"
 	'foldcolumn'	0

 'foldenable' will most-likely be reset to off.  That is when 'foldmethod' is
 is restored to "manual".  The folds themselves are not cleared but they should
 not show up, resetting 'foldenable' is the best way to do that.

 ==============================================================================
 2. Viewing diffs						*view-diffs*

 The effect is that the diff windows show the same text, with the differences
 highlighted.  When scrolling the text, the 'scrollbind' option will make the
 text in other windows to be scrolled as well.  With vertical splits the text
 should be aligned properly.

 The alignment of text will go wrong when:
 - 'wrap' is on, some lines will be wrapped and occupy two or more screen
   lines
 - folds are open in one window but not another
 - 'scrollbind' is off
 - changes have been made to the text
 - "filler" is not present in 'diffopt', deleted/inserted lines makes the
   alignment go wrong

 All the buffers edited in a window where the 'diff' option is set will join in
 the diff.  This is also possible for hidden buffers.  They must have been
 edited in a window first for this to be possible.  To get rid of the hidden
 buffers use `:diffoff!`.

 					*:DiffOrig* *diff-original-file*
 Since 'diff' is a window-local option, it's possible to view the same buffer
 in diff mode in one window and "normal" in another window.  It is also
 possible to view the changes you have made to a buffer since the file was
 loaded.  Since Vim doesn't allow having two buffers for the same file, you
 need another buffer.  This command is useful: >
 	 command DiffOrig vert new | set bt=nofile | r ++edit # | 0d_
 		\ | diffthis | wincmd p | diffthis
 (this is in |defaults.vim|).  Use ":DiffOrig" to see the differences between
 the current buffer and the file it was loaded from.

 A buffer that is unloaded cannot be used for the diff.  But it does work for
 hidden buffers.  You can use ":hide" to close a window without unloading the
 buffer.  If you don't want a buffer to remain used for the diff do ":set
 nodiff" before hiding it.

 						*:dif* *:diff* *:diffupdate*
 :dif[fupdate][!]		Update the diff highlighting and folds.

 Vim attempts to keep the differences updated when you make changes to the
 text.  This mostly takes care of inserted and deleted lines.  Changes within a
 line and more complicated changes do not cause the differences to be updated.
 To force the differences to be updated use: >

 	:diffupdate

 If the ! is included Vim will check if the file was changed externally and
 needs to be reloaded.  It will prompt for each changed file, like `:checktime`
 was used.

 Vim will show filler lines for lines that are missing in one window but are
 present in another.  These lines were inserted in another file or deleted in
 this file.  Removing "filler" from the 'diffopt' option will make Vim not
 display these filler lines.


 Folds are used to hide the text that wasn't changed.  See |folding| for all
 the commands that can be used with folds.

 The context of lines above a difference that are not included in the fold can
 be set with the 'diffopt' option.  For example, to set the context to three
 lines: >

 	:set diffopt=filler,context:3


 The diffs are highlighted with these groups:

 |hl-DiffAdd|	DiffAdd		Added (inserted) lines.  These lines exist in
 				this buffer but not in another.
 |hl-DiffChange|	DiffChange	Changed lines.
 |hl-DiffText|	DiffText	Changed text inside a Changed line.  Exact
 				behavior depends on the `inline:` setting in
 				'diffopt'.
 				With `inline:` set to "simple", Vim finds the
 				first character that is different, and the
 				last character that is different (searching
 				from the end of the line).  The text in
 				between is highlighted.  This means that parts
 				in the middle that are still the same are
 				highlighted anyway.  The 'diffopt' flags
 				"iwhite" and "icase" are used here.
 				With `inline:` set to "char" or "word", Vim
 				uses the internal diff library to perform a
 				detailed diff between the changed blocks and
 				highlight the exact difference between the
 				two.  Will respect any 'diffopt' flag that
 				affects internal diff.
 				Not used when `inline:` is set to "none".
 |hl-DiffTextAdd|  DiffTextAdd	Added text inside a Changed line.  Similar to
 				DiffText, but used when there is no
 				corresponding text in other buffers.  Not used
 				when `inline:` is set to "simple" or "none".
 |hl-DiffDelete|	DiffDelete	Deleted lines.  Also called filler lines,
 				because they don't really exist in this
 				buffer.

 ==============================================================================
 3. Jumping to diffs					*jumpto-diffs*

 Two commands can be used to jump to diffs:
 								*[c*
 	[c		Jump backwards to the previous start of a change.
 			When a count is used, do it that many times.
 								*]c*
 	]c		Jump forwards to the next start of a change.
 			When a count is used, do it that many times.

 It is an error if there is no change for the cursor to move to.

 ==============================================================================
 4. Diff copying			*copy-diffs* *E99* *E100* *E101* *E102* *E103*
 								*merge*
 There are two commands to copy text from one buffer to another.  The result is
 that the buffers will be equal within the specified range.

 							*:diffg* *:diffget*
 :[range]diffg[et] [bufspec]
 		Modify the current buffer to undo difference with another
 		buffer.  If [bufspec] is given, that buffer is used.  If
 		[bufspec] refers to the current buffer then nothing happens.
 		Otherwise this only works if there is one other buffer in diff
 		mode.
 		See below for [range].

 						*:diffpu* *:diffput* *E793*
 :[range]diffpu[t] [bufspec]
 		Modify another buffer to undo difference with the current
 		buffer.  Just like ":diffget" but the other buffer is modified
 		instead of the current one.
 		When [bufspec] is omitted and there is more than one other
 		buffer in diff mode where 'modifiable' is set this fails.
 		See below for [range].

 							*do*
 [count]do	Same as ":diffget" without range.  The "o" stands for "obtain"
 		("dg" can't be used, it could be the start of "dgg"!). Note:
 		this doesn't work in Visual mode.
 		If you give a [count], it is used as the [bufspec] argument
 		for ":diffget".

 							*dp*
 [count]dp	Same as ":diffput" without range.  Note: this doesn't work in
 		Visual mode.
 		If you give a [count], it is used as the [bufspec] argument
 		for ":diffput".


 When no [range] is given, the diff at the cursor position or just above it is
 affected.  There can be deleted lines below the last line of the buffer.  When
 the cursor is on the last line in the buffer and there is no diff above this
 line, and no [range] is given, the diff below the cursor position will be used
 instead.

 When [range] is used, Vim tries to only put or get the specified lines.  When
 there are deleted lines, they will be used if they are between the lines
 specified by [range].

 To be able to put or get those lines to/from another buffer in a [range] it's
 allowed to use 0 and the last line number plus one.  This command gets all
 diffs from the other buffer: >

 	:0,$+1diffget

 Note that deleted lines are displayed, but not counted as text lines.  You
 can't move the cursor into them.  To fill the deleted lines with the lines
 from another buffer use ":diffget" on the line below them.
 								*E787*
 When the buffer that is about to be modified is read-only and the autocommand
 that is triggered by |FileChangedRO| changes buffers the command will fail.
 The autocommand must not change buffers.

 The [bufspec] argument above can be a buffer number, a pattern for a buffer
 name or a part of a buffer name.  Examples:

 	:diffget		Use the other buffer which is in diff mode
 	:diffget 3		Use buffer 3
 	:diffget v2		Use the buffer which matches "v2" and is in
 				diff mode (e.g., "file.c.v2")

 ==============================================================================
 5. Diff options						*diff-options*

 Also see |'diffopt'| and the "diff" item of |'fillchars'|.

 					    *diff-slow* *diff_translations*
 For very long lines, the diff syntax highlighting might be slow, especially
 since it tries to match all different kind of localisations. To disable
 localisations and speed up the syntax highlighting, set the global variable
 g:diff_translations to zero: >

     let g:diff_translations = 0
 <
 After setting this variable, reload the syntax script: >

     set syntax=diff
 <


 FINDING THE DIFFERENCES					*diff-diffexpr*

 The 'diffexpr' option can be set to use something else than the internal diff
 support or the standard "diff" program to compare two files and find the
 differences. *E959*

 When 'diffexpr' is empty, Vim uses this command to find the differences
 between file1 and file2: >

 	diff file1 file2 > outfile

 The ">" is replaced with the value of 'shellredir'.

 The output of "diff" must be a normal "ed" style diff or a unified diff.  A
 context diff will NOT work.  For a unified diff no context lines can be used.
 Using "diff -u" will NOT work, use "diff -U0".

 This example explains the format that Vim expects for the "ed" style diff: >

 	1a2
 	> bbb
 	4d4
 	< 111
 	7c7
 	< GGG
 	---
 	> ggg

 The "1a2" item appends the line "bbb".
 The "4d4" item deletes the line "111".
 The "7c7" item replaces the line "GGG" with "ggg".

 When 'diffexpr' is not empty, Vim evaluates it to obtain a diff file in the
 format mentioned.  These variables are set to the file names used:

 	v:fname_in		original file
 	v:fname_new		new version of the same file
 	v:fname_out		where to write the resulting diff file

 Additionally, 'diffexpr' should take care of "icase" and "iwhite" in the
 'diffopt' option.  'diffexpr' cannot change the value of 'lines' and
 'columns'.

 The advantage of using a function call without arguments is that it is faster,
 see |expr-option-function|.

 Example (this does almost the same as 'diffexpr' being empty): >

 	set diffexpr=MyDiff()
 	function MyDiff()
 	   let opt = ""
 	   if &diffopt =~ "icase"
 	     let opt = opt .. "-i "
 	   endif
 	   if &diffopt =~ "iwhite"
 	     let opt = opt .. "-b "
 	   endif
 	   silent execute "!diff -a --binary " .. opt .. v:fname_in .. " " .. v:fname_new ..
 		\  " > " .. v:fname_out
 	   redraw!
 	endfunction

 The "-a" argument is used to force comparing the files as text, comparing as
 binaries isn't useful.  The "--binary" argument makes the files read in binary
 mode, so that a CTRL-Z doesn't end the text on DOS.

 The `redraw!` command may not be needed, depending on whether executing a
 shell command shows something on the display or not.

 If the 'diffexpr' expression starts with s: or |<SID>|, then it is replaced
 with the script ID (|local-function|). Example: >
 		set diffexpr=s:MyDiffExpr()
 		set diffexpr=<SID>SomeDiffExpr()
 Otherwise, the expression is evaluated in the context of the script where the
 option was set, thus script-local items are available.

 						*E810* *E97*
 Vim will do a test if the diff output looks alright.  If it doesn't, you will
 get an error message.  Possible causes:
 -  The "diff" program cannot be executed.
 -  The "diff" program doesn't produce normal "ed" style diffs (see above).
 -  The 'shell' and associated options are not set correctly.  Try if filtering
    works with a command like ":!sort".
 -  You are using 'diffexpr' and it doesn't work.
 If it's not clear what the problem is set the 'verbose' option to one or more
 to see more messages.

 The self-installing Vim for MS-Windows includes a diff program.  If you don't
 have it you might want to download a diff.exe.  For example from
 http://gnuwin32.sourceforge.net/packages/diffutils.htm.


 USING PATCHES					*diff-patchexpr*

 The 'patchexpr' option can be set to use something else than the standard
 "patch" program.

 When 'patchexpr' is empty, Vim will call the "patch" program like this: >

 	patch -o outfile origfile < patchfile

 This should work fine with most versions of the "patch" program.  Note that a
 CR in the middle of a line may cause problems, it is seen as a line break.

 If the default doesn't work for you, set the 'patchexpr' to an expression that
 will have the same effect.  These variables are set to the file names used:

 	v:fname_in		original file
 	v:fname_diff		patch file
 	v:fname_out		resulting patched file

 The advantage of using a function call without arguments is that it is faster,
 see |expr-option-function|.

 Example (this does the same as 'patchexpr' being empty): >

 	set patchexpr=MyPatch()
 	function MyPatch()
 	   :call system("patch -o " .. v:fname_out .. " " .. v:fname_in ..
 	   \  " < " .. v:fname_diff)
 	endfunction

 Make sure that using the "patch" program doesn't have unwanted side effects.
 For example, watch out for additionally generated files, which should be
 deleted.  It should just patch the file and nothing else.
    Vim will change directory to "/tmp" or another temp directory before
 evaluating 'patchexpr'.  This hopefully avoids that files in the current
 directory are accidentally patched.  Vim will also delete files starting with
 v:fname_in and ending in ".rej" and ".orig".

 If the 'patchexpr' expression starts with s: or |<SID>|, then it is replaced
 with the script ID (|local-function|). Example: >
 		set patchexpr=s:MyPatchExpr()
 		set patchexpr=<SID>SomePatchExpr()
 Otherwise, the expression is evaluated in the context of the script where the
 option was set, thus script-local items are available.


 DIFF FUNCTION EXAMPLES				*diff-func-examples*

 Some examples for using the |diff()| function to compute the diff indices
 between two Lists of strings are below.
 >
   " some lines are changed
   :echo diff(['abc', 'def', 'ghi'], ['abx', 'rrr', 'xhi'], {'output': 'indices'})
    [{'from_idx': 0, 'from_count': 3, 'to_idx': 0, 'to_count': 3}]

   " few lines added at the beginning
   :echo diff(['ghi'], ['abc', 'def', 'ghi'], {'output': 'indices'})
    [{'from_idx': 0, 'from_count': 0, 'to_idx': 0, 'to_count': 2}]

   " few lines removed from the beginning
   :echo diff(['abc', 'def', 'ghi'], ['ghi'], {'output': 'indices'})
    [{'from_idx': 0, 'from_count': 2, 'to_idx': 0, 'to_count': 0}]

   " few lines added in the middle
   :echo diff(['abc', 'jkl'], ['abc', 'def', 'ghi', 'jkl'], {'output': 'indices'})
    [{'from_idx': 1, 'from_count': 0, 'to_idx': 1, 'to_count': 2}]

   " few lines removed in the middle
   :echo diff(['abc', 'def', 'ghi', 'jkl'], ['abc', 'jkl'], {'output': 'indices'})
    [{'from_idx': 1, 'from_count': 2, 'to_idx': 1, 'to_count': 0}]

   " few lines added at the end
   :echo diff(['abc'], ['abc', 'def', 'ghi'], {'output': 'indices'})
    [{'from_idx': 1, 'from_count': 0, 'to_idx': 1, 'to_count': 2}]

   " few lines removed from the end
   :echo diff(['abc', 'def', 'ghi'], ['abc'], {'output': 'indices'})
    [{'from_idx': 1, 'from_count': 2, 'to_idx': 1, 'to_count': 0}]

   " disjointed changes
   :echo diff(['ab', 'def', 'ghi', 'jkl'], ['abc', 'def', 'ghi', 'jk'], {'output': 'indices', 'context': 0})
    [{'from_idx': 0, 'from_count': 1, 'to_idx': 0, 'to_count': 1},
     {'from_idx': 3, 'from_count': 1, 'to_idx': 3, 'to_count': 1}]

   " disjointed changes with context length 1
   :echo diff(['ab', 'def', 'ghi', 'jkl'], ['abc', 'def', 'ghi', 'jk'], {'output': 'indices', 'context': 1})
    [{'from_idx': 0, 'from_count': 4, 'to_idx': 0, 'to_count': 4}]

 <

  vim:tw=78:ts=8:noet:ft=help:norl:
	diff.txt For Vim version 9.1. Last change: 2025 Jun 20


	VIM REFERENCE MANUAL by Bram Moolenaar


	diff vimdiff gvimdiff diff-mode
	This file describes the \|+diff\| feature: Showing differences between two to
	eight versions of the same file.

	The basics are explained in section \|08.7\| of the user manual.

	1. Starting diff mode \|start-vimdiff\|
	2. Viewing diffs \|view-diffs\|
	3. Jumping to diffs \|jumpto-diffs\|
	4. Copying diffs \|copy-diffs\|
	5. Diff options \|diff-options\|

	==============================================================================
	1. Starting diff mode start-vimdiff

	The easiest way to start editing in diff mode is with the "vimdiff" command.
	This starts Vim as usual, and additionally sets up for viewing the differences
	between the arguments. >

	vimdiff file1 file2 [file3 [file4]]

	This is equivalent to: >

	vim -d file1 file2 [file3 [file4]]

	You may also use "gvimdiff" or "vim -d -g". The GUI is started then.
	You may also use "viewdiff" or "gviewdiff". Vim starts in readonly mode then.
	"r" may be prepended for restricted mode (see \|-Z\|).

	The second and following arguments may also be a directory name. Vim will
	then append the file name of the first argument to the directory name to find
	the file.

	By default an internal diff library will be used. When 'diffopt' or
	'diffexpr' has been set an external "diff" command will be used. This only
	works when such a diff program is available.

	Diffs are local to the current tab page \|tab-page\|. You can't see diffs with
	a window in another tab page. This does make it possible to have several
	diffs at the same time, each in their own tab page.

	What happens is that Vim opens a window for each of the files. This is like
	using the \|-O\| argument. This uses vertical splits. If you prefer horizontal
	splits add the \|-o\| argument: >

	vimdiff -o file1 file2 [file3 [file4]]

	If you always prefer horizontal splits include "horizontal" in 'diffopt'.

	In each of the edited files these options are set:

	'diff' on
	'scrollbind' on
	'cursorbind' on
	'scrollopt' includes "hor"
	'wrap' off, or leave as-is if 'diffopt' includes "followwrap"
	'foldmethod' "diff"
	'foldcolumn' value from 'diffopt', default is 2

	These options are set local to the window. When editing another file they are
	reset to the global value.
	The options can still be overruled from a modeline when re-editing the file.
	However, 'foldmethod' and 'wrap' won't be set from a modeline when 'diff' is
	set.
	See `:diffoff` for an easy way to revert the options.

	The differences shown are actually the differences in the buffer. Thus if you
	make changes after loading a file, these will be included in the displayed
	diffs. You might have to do ":diffupdate" now and then, not all changes are
	immediately taken into account, especially when using an external diff command.

	In your .vimrc file you could do something special when Vim was started in
	diff mode. You could use a construct like this: >

	if &diff
	setup for diff mode
	else
	setup for non-diff mode
	endif

	While already in Vim you can start diff mode in three ways.

	E98
	:diffs[plit] {filename} :diffs :diffsplit
	Open a new window on the file {filename}. The options are set
	as for "vimdiff" for the current and the newly opened window.
	Also see 'diffexpr'.

	:difft :diffthis
	:difft[his] Make the current window part of the diff windows. This sets
	the options like for "vimdiff".

	:diffp[atch] {patchfile} E816 :diffp :diffpatch
	Use the current buffer, patch it with the diff found in
	{patchfile} and open a buffer on the result. The options are
	set as for "vimdiff".
	{patchfile} can be in any format that the "patch" program
	understands or 'patchexpr' can handle.
	Note that {patchfile} should only contain a diff for one file,
	the current file. If {patchfile} contains diffs for other
	files as well, the results are unpredictable. Vim changes
	directory to /tmp to avoid files in the current directory
	accidentally being patched. But it may still result in
	various ".rej" files to be created. And when absolute path
	names are present these files may get patched anyway.
	Using the "patch" command is not allowed in \|restricted-mode\|.

	To make these commands use a vertical split, prepend \|:vertical\|. Examples: >

	:vert diffsplit main.c~
	:vert diffpatch /tmp/diff

	If you always prefer a vertical split include "vertical" in 'diffopt'.

	E96
	There can be up to eight buffers with 'diff' set.

	Since the option values are remembered with the buffer, you can edit another
	file for a moment and come back to the same file and be in diff mode again.

	:diffo :diffoff
	:diffo[ff] Switch off diff mode for the current window. Resets related
	options also when 'diff' was not set.

	:diffo[ff]! Switch off diff mode for the current window and in all windows
	in the current tab page where 'diff' is set. Resetting
	related options only happens in a window that has 'diff' set,
	if the current window does not have 'diff' set then no options
	in it are changed.
	Hidden buffers are also removed from the list of diff'ed
	buffers.

	The `:diffoff` command resets the relevant options to the values they had when
	using `:diffsplit`, `:diffpatch`, `:diffthis`. or starting Vim in diff mode.
	When using `:diffoff` twice the last saved values are restored.
	Otherwise they are set to their default value:

	'diff' off
	'scrollbind' off
	'cursorbind' off
	'scrollopt' without "hor"
	'wrap' on, or leave as-is if 'diffopt' includes "followwrap"
	'foldmethod' "manual"
	'foldcolumn' 0

	'foldenable' will most-likely be reset to off. That is when 'foldmethod' is
	is restored to "manual". The folds themselves are not cleared but they should
	not show up, resetting 'foldenable' is the best way to do that.

	==============================================================================
	2. Viewing diffs view-diffs

	The effect is that the diff windows show the same text, with the differences
	highlighted. When scrolling the text, the 'scrollbind' option will make the
	text in other windows to be scrolled as well. With vertical splits the text
	should be aligned properly.

	The alignment of text will go wrong when:
	- 'wrap' is on, some lines will be wrapped and occupy two or more screen
	lines
	- folds are open in one window but not another
	- 'scrollbind' is off
	- changes have been made to the text
	- "filler" is not present in 'diffopt', deleted/inserted lines makes the
	alignment go wrong

	All the buffers edited in a window where the 'diff' option is set will join in
	the diff. This is also possible for hidden buffers. They must have been
	edited in a window first for this to be possible. To get rid of the hidden
	buffers use `:diffoff!`.

	:DiffOrig diff-original-file
	Since 'diff' is a window-local option, it's possible to view the same buffer
	in diff mode in one window and "normal" in another window. It is also
	possible to view the changes you have made to a buffer since the file was
	loaded. Since Vim doesn't allow having two buffers for the same file, you
	need another buffer. This command is useful: >
	command DiffOrig vert new \| set bt=nofile \| r ++edit # \| 0d_
	\ \| diffthis \| wincmd p \| diffthis
	(this is in \|defaults.vim\|). Use ":DiffOrig" to see the differences between
	the current buffer and the file it was loaded from.

	A buffer that is unloaded cannot be used for the diff. But it does work for
	hidden buffers. You can use ":hide" to close a window without unloading the
	buffer. If you don't want a buffer to remain used for the diff do ":set
	nodiff" before hiding it.

	:dif :diff :diffupdate
	:dif[fupdate][!] Update the diff highlighting and folds.

	Vim attempts to keep the differences updated when you make changes to the
	text. This mostly takes care of inserted and deleted lines. Changes within a
	line and more complicated changes do not cause the differences to be updated.
	To force the differences to be updated use: >

	:diffupdate

	If the ! is included Vim will check if the file was changed externally and
	needs to be reloaded. It will prompt for each changed file, like `:checktime`
	was used.

	Vim will show filler lines for lines that are missing in one window but are
	present in another. These lines were inserted in another file or deleted in
	this file. Removing "filler" from the 'diffopt' option will make Vim not
	display these filler lines.


	Folds are used to hide the text that wasn't changed. See \|folding\| for all
	the commands that can be used with folds.

	The context of lines above a difference that are not included in the fold can
	be set with the 'diffopt' option. For example, to set the context to three
	lines: >

	:set diffopt=filler,context:3


	The diffs are highlighted with these groups:

	\|hl-DiffAdd\| DiffAdd Added (inserted) lines. These lines exist in
	this buffer but not in another.
	\|hl-DiffChange\| DiffChange Changed lines.
	\|hl-DiffText\| DiffText Changed text inside a Changed line. Exact
	behavior depends on the `inline:` setting in
	'diffopt'.
	With `inline:` set to "simple", Vim finds the
	first character that is different, and the
	last character that is different (searching
	from the end of the line). The text in
	between is highlighted. This means that parts
	in the middle that are still the same are
	highlighted anyway. The 'diffopt' flags
	"iwhite" and "icase" are used here.
	With `inline:` set to "char" or "word", Vim
	uses the internal diff library to perform a
	detailed diff between the changed blocks and
	highlight the exact difference between the
	two. Will respect any 'diffopt' flag that
	affects internal diff.
	Not used when `inline:` is set to "none".
	\|hl-DiffTextAdd\| DiffTextAdd Added text inside a Changed line. Similar to
	DiffText, but used when there is no
	corresponding text in other buffers. Not used
	when `inline:` is set to "simple" or "none".
	\|hl-DiffDelete\| DiffDelete Deleted lines. Also called filler lines,
	because they don't really exist in this
	buffer.

	==============================================================================
	3. Jumping to diffs jumpto-diffs

	Two commands can be used to jump to diffs:
	[c
	[c Jump backwards to the previous start of a change.
	When a count is used, do it that many times.
	]c
	]c Jump forwards to the next start of a change.
	When a count is used, do it that many times.

	It is an error if there is no change for the cursor to move to.

	==============================================================================
	4. Diff copying copy-diffs E99 E100 E101 E102 E103
	merge
	There are two commands to copy text from one buffer to another. The result is
	that the buffers will be equal within the specified range.

	:diffg :diffget
	:[range]diffg[et] [bufspec]
	Modify the current buffer to undo difference with another
	buffer. If [bufspec] is given, that buffer is used. If
	[bufspec] refers to the current buffer then nothing happens.
	Otherwise this only works if there is one other buffer in diff
	mode.
	See below for [range].

	:diffpu :diffput E793
	:[range]diffpu[t] [bufspec]
	Modify another buffer to undo difference with the current
	buffer. Just like ":diffget" but the other buffer is modified
	instead of the current one.
	When [bufspec] is omitted and there is more than one other
	buffer in diff mode where 'modifiable' is set this fails.
	See below for [range].

	do
	[count]do Same as ":diffget" without range. The "o" stands for "obtain"
	("dg" can't be used, it could be the start of "dgg"!). Note:
	this doesn't work in Visual mode.
	If you give a [count], it is used as the [bufspec] argument
	for ":diffget".

	dp
	[count]dp Same as ":diffput" without range. Note: this doesn't work in
	Visual mode.
	If you give a [count], it is used as the [bufspec] argument
	for ":diffput".


	When no [range] is given, the diff at the cursor position or just above it is
	affected. There can be deleted lines below the last line of the buffer. When
	the cursor is on the last line in the buffer and there is no diff above this
	line, and no [range] is given, the diff below the cursor position will be used
	instead.

	When [range] is used, Vim tries to only put or get the specified lines. When
	there are deleted lines, they will be used if they are between the lines
	specified by [range].

	To be able to put or get those lines to/from another buffer in a [range] it's
	allowed to use 0 and the last line number plus one. This command gets all
	diffs from the other buffer: >

	:0,$+1diffget

	Note that deleted lines are displayed, but not counted as text lines. You
	can't move the cursor into them. To fill the deleted lines with the lines
	from another buffer use ":diffget" on the line below them.
	E787
	When the buffer that is about to be modified is read-only and the autocommand
	that is triggered by \|FileChangedRO\| changes buffers the command will fail.
	The autocommand must not change buffers.

	The [bufspec] argument above can be a buffer number, a pattern for a buffer
	name or a part of a buffer name. Examples:

	:diffget Use the other buffer which is in diff mode
	:diffget 3 Use buffer 3
	:diffget v2 Use the buffer which matches "v2" and is in
	diff mode (e.g., "file.c.v2")

	==============================================================================
	5. Diff options diff-options

	Also see \|'diffopt'\| and the "diff" item of \|'fillchars'\|.

	diff-slow diff_translations
	For very long lines, the diff syntax highlighting might be slow, especially
	since it tries to match all different kind of localisations. To disable
	localisations and speed up the syntax highlighting, set the global variable
	g:diff_translations to zero: >

	let g:diff_translations = 0
	<
	After setting this variable, reload the syntax script: >

	set syntax=diff
	<


	FINDING THE DIFFERENCES diff-diffexpr

	The 'diffexpr' option can be set to use something else than the internal diff
	support or the standard "diff" program to compare two files and find the
	differences. E959

	When 'diffexpr' is empty, Vim uses this command to find the differences
	between file1 and file2: >

	diff file1 file2 > outfile

	The ">" is replaced with the value of 'shellredir'.

	The output of "diff" must be a normal "ed" style diff or a unified diff. A
	context diff will NOT work. For a unified diff no context lines can be used.
	Using "diff -u" will NOT work, use "diff -U0".

	This example explains the format that Vim expects for the "ed" style diff: >

	1a2
	> bbb
	4d4
	< 111
	7c7
	< GGG
	---
	> ggg

	The "1a2" item appends the line "bbb".
	The "4d4" item deletes the line "111".
	The "7c7" item replaces the line "GGG" with "ggg".

	When 'diffexpr' is not empty, Vim evaluates it to obtain a diff file in the
	format mentioned. These variables are set to the file names used:

	v:fname_in original file
	v:fname_new new version of the same file
	v:fname_out where to write the resulting diff file

	Additionally, 'diffexpr' should take care of "icase" and "iwhite" in the
	'diffopt' option. 'diffexpr' cannot change the value of 'lines' and
	'columns'.

	The advantage of using a function call without arguments is that it is faster,
	see \|expr-option-function\|.

	Example (this does almost the same as 'diffexpr' being empty): >

	set diffexpr=MyDiff()
	function MyDiff()
	let opt = ""
	if &diffopt =~ "icase"
	let opt = opt .. "-i "
	endif
	if &diffopt =~ "iwhite"
	let opt = opt .. "-b "
	endif
	silent execute "!diff -a --binary " .. opt .. v:fname_in .. " " .. v:fname_new ..
	\ " > " .. v:fname_out
	redraw!
	endfunction

	The "-a" argument is used to force comparing the files as text, comparing as
	binaries isn't useful. The "--binary" argument makes the files read in binary
	mode, so that a CTRL-Z doesn't end the text on DOS.

	The `redraw!` command may not be needed, depending on whether executing a
	shell command shows something on the display or not.

	If the 'diffexpr' expression starts with s: or \|<SID>\|, then it is replaced
	with the script ID (\|local-function\|). Example: >
	set diffexpr=s:MyDiffExpr()
	set diffexpr=<SID>SomeDiffExpr()
	Otherwise, the expression is evaluated in the context of the script where the
	option was set, thus script-local items are available.

	E810 E97
	Vim will do a test if the diff output looks alright. If it doesn't, you will
	get an error message. Possible causes:
	- The "diff" program cannot be executed.
	- The "diff" program doesn't produce normal "ed" style diffs (see above).
	- The 'shell' and associated options are not set correctly. Try if filtering
	works with a command like ":!sort".
	- You are using 'diffexpr' and it doesn't work.
	If it's not clear what the problem is set the 'verbose' option to one or more
	to see more messages.

	The self-installing Vim for MS-Windows includes a diff program. If you don't
	have it you might want to download a diff.exe. For example from
	http://gnuwin32.sourceforge.net/packages/diffutils.htm.


	USING PATCHES diff-patchexpr

	The 'patchexpr' option can be set to use something else than the standard
	"patch" program.

	When 'patchexpr' is empty, Vim will call the "patch" program like this: >

	patch -o outfile origfile < patchfile

	This should work fine with most versions of the "patch" program. Note that a
	CR in the middle of a line may cause problems, it is seen as a line break.

	If the default doesn't work for you, set the 'patchexpr' to an expression that
	will have the same effect. These variables are set to the file names used:

	v:fname_in original file
	v:fname_diff patch file
	v:fname_out resulting patched file

	The advantage of using a function call without arguments is that it is faster,
	see \|expr-option-function\|.

	Example (this does the same as 'patchexpr' being empty): >

	set patchexpr=MyPatch()
	function MyPatch()
	:call system("patch -o " .. v:fname_out .. " " .. v:fname_in ..
	\ " < " .. v:fname_diff)
	endfunction

	Make sure that using the "patch" program doesn't have unwanted side effects.
	For example, watch out for additionally generated files, which should be
	deleted. It should just patch the file and nothing else.
	Vim will change directory to "/tmp" or another temp directory before
	evaluating 'patchexpr'. This hopefully avoids that files in the current
	directory are accidentally patched. Vim will also delete files starting with
	v:fname_in and ending in ".rej" and ".orig".

	If the 'patchexpr' expression starts with s: or \|<SID>\|, then it is replaced
	with the script ID (\|local-function\|). Example: >
	set patchexpr=s:MyPatchExpr()
	set patchexpr=<SID>SomePatchExpr()
	Otherwise, the expression is evaluated in the context of the script where the
	option was set, thus script-local items are available.


	DIFF FUNCTION EXAMPLES diff-func-examples

	Some examples for using the \|diff()\| function to compute the diff indices
	between two Lists of strings are below.
	>
	" some lines are changed
	:echo diff(['abc', 'def', 'ghi'], ['abx', 'rrr', 'xhi'], {'output': 'indices'})
	[{'from_idx': 0, 'from_count': 3, 'to_idx': 0, 'to_count': 3}]

	" few lines added at the beginning
	:echo diff(['ghi'], ['abc', 'def', 'ghi'], {'output': 'indices'})
	[{'from_idx': 0, 'from_count': 0, 'to_idx': 0, 'to_count': 2}]

	" few lines removed from the beginning
	:echo diff(['abc', 'def', 'ghi'], ['ghi'], {'output': 'indices'})
	[{'from_idx': 0, 'from_count': 2, 'to_idx': 0, 'to_count': 0}]

	" few lines added in the middle
	:echo diff(['abc', 'jkl'], ['abc', 'def', 'ghi', 'jkl'], {'output': 'indices'})
	[{'from_idx': 1, 'from_count': 0, 'to_idx': 1, 'to_count': 2}]

	" few lines removed in the middle
	:echo diff(['abc', 'def', 'ghi', 'jkl'], ['abc', 'jkl'], {'output': 'indices'})
	[{'from_idx': 1, 'from_count': 2, 'to_idx': 1, 'to_count': 0}]

	" few lines added at the end
	:echo diff(['abc'], ['abc', 'def', 'ghi'], {'output': 'indices'})
	[{'from_idx': 1, 'from_count': 0, 'to_idx': 1, 'to_count': 2}]

	" few lines removed from the end
	:echo diff(['abc', 'def', 'ghi'], ['abc'], {'output': 'indices'})
	[{'from_idx': 1, 'from_count': 2, 'to_idx': 1, 'to_count': 0}]

	" disjointed changes
	:echo diff(['ab', 'def', 'ghi', 'jkl'], ['abc', 'def', 'ghi', 'jk'], {'output': 'indices', 'context': 0})
	[{'from_idx': 0, 'from_count': 1, 'to_idx': 0, 'to_count': 1},
	{'from_idx': 3, 'from_count': 1, 'to_idx': 3, 'to_count': 1}]

	" disjointed changes with context length 1
	:echo diff(['ab', 'def', 'ghi', 'jkl'], ['abc', 'def', 'ghi', 'jk'], {'output': 'indices', 'context': 1})
	[{'from_idx': 0, 'from_count': 4, 'to_idx': 0, 'to_count': 4}]

	<

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