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- *diff.txt* For Vim version 6.2. Last change: 2002 Nov 10
-
-
- VIM REFERENCE MANUAL by Bram Moolenaar
-
-
- *diff* *vimdiff* *gvimdiff* *diff-mode*
- This file describes the +diff feature: Showing differences between two or
- three versions of the same file.
-
- The basics are explained in section |08.7| of the user manual.
-
- 1. Starting diff mode |vimdiff|
- 2. Viewing diffs |view-diffs|
- 3. Jumping to diffs |jumpto-diffs|
- 4. Copying diffs |copy-diffs|
- 5. Diff options |diff-options|
-
- {not in Vi}
-
- ==============================================================================
- 1. Starting diff mode
-
- 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 -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.
-
- This only works when a standard "diff" command is available. See 'diffexpr'.
-
- 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]
-
- In each of the edited files these options are set:
-
- 'diff' on
- 'scrollbind' on
- 'scrollopt' includes "hor"
- 'wrap' off
- 'foldmethod' "diff"
- 'foldcolumn' 2
-
- These options are set local to the window. Thus when splitting the window or
- editing another file they are reset to the global value.
-
- 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.
-
- 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*
- :diffsplit {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*
- :diffthis Make the current window part of the diff windows. This sets
- the option like for "vimdiff".
-
- :diffpatch {patchfile} *: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.
-
- To make these commands use a vertical split, prepend |:vertical|. Examples: >
-
- :vert diffsplit main.c~
- :vert diffpatch /tmp/diff
- <
- *E96*
- There can be up to four 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.
- If you don't want diff mode, reset the 'diff' option. And you probably want
- to get rid of the fold column: >
-
- :set nodiff
- :set foldcolumn=0
-
- ==============================================================================
- 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.
-
- 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, but since Vim doesn't
- allow having two buffers for the same file, you need to make a copy the
- original file and diff with that. For example: >
- :!cp % tempfile
- :diffsplit tempfile
-
- 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.
-
-
- *:diffu* *:diffupdate*
- 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
-
-
- 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. 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.
- |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*
-
- 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.
- Otherwise this only works if there is one other buffer in diff
- mode.
- See below for [range].
-
- *:diffpu* *:diffput*
- :[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.
- See below for [range].
-
- *do*
- do Same as ":diffget" without argument or range. The "o" stands
- for "obtain" ("dg" can't be used for this!).
-
- *dp*
- dp Same as ":diffput" without argument or range.
-
- When no [range] is given, the diff at the cursor position or just above it is
- affected. When [range] is used, Vim tries to only put or get the specified
- lines. When there are deleted lines, this may not always be possible.
-
- 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")
-
- 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.
-
- There can be deleted lines below the last line of the buffer. To be able to
- get those lines from another buffer it's allowed to use the last line number
- plus one. This command gets all diffs from the other buffer: >
-
- :1,$+1diffget
-
- ==============================================================================
- 5. Diff options *diff-options*
-
- Also see |'diffopt'| and the "diff" item of |'fillchars'|.
-
-
- FINDING THE DIFFERENCES *diff-diffexpr*
-
- The 'diffexpr' option can be set to use something else than the standard
- "diff" program to compare two files and find the differences.
-
- 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. Do NOT use a context
- diff. This example explains the format that Vim expects: >
-
- 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 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 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'.
-
- Example (this does the same as 'diffexpr' being empty, but adds the "-a"
- flag to force comparing them as text): >
-
- 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 " . opt . v:fname_in . " " . v:fname_new .
- \ " > " . v:fname_out
- endfunction
- <
- *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.
-
-
- 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
-
- Example (this does the same as 'patchexpr' being empty): >
-
- let 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".
-
- vim:tw=78:ts=8:ft=help:norl:
-