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date Sun, 13 Jun 2004 20:20:40 +0000
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1 *diff.txt* For Vim version 7.0aa. Last change: 2004 May 01
2
3
4 VIM REFERENCE MANUAL by Bram Moolenaar
5
6
7 *diff* *vimdiff* *gvimdiff* *diff-mode*
8 This file describes the +diff feature: Showing differences between two or
9 three versions of the same file.
10
11 The basics are explained in section |08.7| of the user manual.
12
13 1. Starting diff mode |vimdiff|
14 2. Viewing diffs |view-diffs|
15 3. Jumping to diffs |jumpto-diffs|
16 4. Copying diffs |copy-diffs|
17 5. Diff options |diff-options|
18
19 {not in Vi}
20
21 ==============================================================================
22 1. Starting diff mode
23
24 The easiest way to start editing in diff mode is with the "vimdiff" command.
25 This starts Vim as usual, and additionally sets up for viewing the differences
26 between the arguments. >
27
28 vimdiff file1 file2 [file3 [file4]]
29
30 This is equivalent to: >
31
32 vim -d file1 file2 [file3 [file4]]
33
34 You may also use "gvimdiff" or "vim -d -g". The GUI is started then.
35 You may also use "viewdiff" or "gviewdiff". Vim starts in readonly mode then.
36 "r" may be prepended for restricted mode (see |-Z|).
37
38 The second and following arguments may also be a directory name. Vim will
39 then append the file name of the first argument to the directory name to find
40 the file.
41
42 This only works when a standard "diff" command is available. See 'diffexpr'.
43
44 What happens is that Vim opens a window for each of the files. This is like
45 using the |-O| argument. This uses vertical splits. If you prefer horizontal
46 splits add the |-o| argument: >
47
48 vimdiff -o file1 file2 [file3]
49
50 In each of the edited files these options are set:
51
52 'diff' on
53 'scrollbind' on
54 'scrollopt' includes "hor"
55 'wrap' off
56 'foldmethod' "diff"
57 'foldcolumn' 2
58
59 These options are set local to the window. When editing another file they are
60 reset to the global value.
61
62 The differences shown are actually the differences in the buffer. Thus if you
63 make changes after loading a file, these will be included in the displayed
64 diffs. You might have to do ":diffupdate" now and then, not all changes are
65 immediately taken into account.
66
67 In your .vimrc file you could do something special when Vim was started in
68 diff mode. You could use a construct like this: >
69
70 if &diff
71 setup for diff mode
72 else
73 setup for non-diff mode
74 endif
75
76 While already in Vim you can start diff mode in three ways.
77
78 *E98*
79 :diffsplit {filename} *:diffs* *:diffsplit*
80 Open a new window on the file {filename}. The options are set
81 as for "vimdiff" for the current and the newly opened window.
82 Also see 'diffexpr'.
83
84 *:difft* *:diffthis*
85 :diffthis Make the current window part of the diff windows. This sets
86 the option like for "vimdiff".
87
88 :diffpatch {patchfile} *:diffp* *:diffpatch*
89 Use the current buffer, patch it with the diff found in
90 {patchfile} and open a buffer on the result. The options are
91 set as for "vimdiff".
92 {patchfile} can be in any format that the "patch" program
93 understands or 'patchexpr' can handle.
94 Note that {patchfile} should only contain a diff for one file,
95 the current file. If {patchfile} contains diffs for other
96 files as well, the results are unpredictable. Vim changes
97 directory to /tmp to avoid files in the current directory
98 accidentally being patched. But it may still result in
99 various ".rej" files to be created. And when absolute path
100 names are present these files may get patched anyway.
101
102 To make these commands use a vertical split, prepend |:vertical|. Examples: >
103
104 :vert diffsplit main.c~
105 :vert diffpatch /tmp/diff
106 <
107 *E96*
108 There can be up to four buffers with 'diff' set.
109
110 Since the option values are remembered with the buffer, you can edit another
111 file for a moment and come back to the same file and be in diff mode again.
112 If you don't want diff mode, reset the 'diff' option. And you probably want
113 to get rid of the fold column: >
114
115 :set nodiff foldcolumn=0
116
117 ==============================================================================
118 2. Viewing diffs *view-diffs*
119
120 The effect is that the diff windows show the same text, with the differences
121 highlighted. When scrolling the text, the 'scrollbind' option will make the
122 text in other windows to be scrolled as well. With vertical splits the text
123 should be aligned properly.
124
125 The alignment of text will go wrong when:
126 - 'wrap' is on, some lines will be wrapped and occupy two or more screen
127 lines
128 - folds are open in one window but not another
129 - 'scrollbind' is off
130 - changes have been made to the text
131 - "filler" is not present in 'diffopt', deleted/inserted lines makes the
132 alignment go wrong
133
134 All the buffers edited in a window where the 'diff' option is set will join in
135 the diff. This is also possible for hidden buffers. They must have been
136 edited in a window first for this to be possible.
137
138 Since 'diff' is a window-local option, it's possible to view the same buffer
139 in diff mode in one window and "normal" in another window. It is also
140 possible to view the changes you have made to a buffer, but since Vim doesn't
141 allow having two buffers for the same file, you need to make a copy of the
142 original file and diff with that. For example: >
143 :!cp % tempfile
144 :diffsplit tempfile
145
146 A buffer that is unloaded cannot be used for the diff. But it does work for
147 hidden buffers. You can use ":hide" to close a window without unloading the
148 buffer.
149
150
151 *:diffu* *:diffupdate*
152 Vim attempts to keep the differences updated when you make changes to the
153 text. This mostly takes care of inserted and deleted lines. Changes within a
154 line and more complicated changes do not cause the differences to be updated.
155 To force the differences to be updated use: >
156
157 :diffupdate
158
159
160 Vim will show filler lines for lines that are missing in one window but are
161 present in another. These lines were inserted in another file or deleted in
162 this file. Removing "filler" from the 'diffopt' option will make Vim not
163 display these filler lines.
164
165
166 Folds are used to hide the text that wasn't changed. See |folding| for all
167 the commands that can be used with folds.
168
169 The context of lines above a difference that are not included in the fold can
170 be set with the 'diffopt' option. For example, to set the context to three
171 lines: >
172
173 :set diffopt=filler,context:3
174
175
176 The diffs are highlighted with these groups:
177
178 |hl-DiffAdd| DiffAdd Added (inserted) lines. These lines exist in
179 this buffer but not in another.
180 |hl-DiffChange| DiffChange Changed lines.
181 |hl-DiffText| DiffText Changed text inside a Changed line. Vim
182 finds the first character that is different,
183 and the last character that is different
184 (searching from the end of the line). The
185 text in between is highlighted. This means
186 that parts in the middle that are still the
187 same are highlighted anyway.
188 |hl-DiffDelete| DiffDelete Deleted lines. Also called filler lines,
189 because they don't really exist in this
190 buffer.
191
192 ==============================================================================
193 3. Jumping to diffs *jumpto-diffs*
194
195 Two commands can be used to jump to diffs:
196 *[c*
197 [c Jump backwards to the previous start of a change.
198 When a count is used, do it that many times.
199 *]c*
200 ]c Jump forwards to the next start of a change.
201 When a count is used, do it that many times.
202
203 It is an error if there is no change for the cursor to move to.
204
205 ==============================================================================
206 4. Diff copying *copy-diffs* *E99* *E100* *E101* *E102* *E103*
207
208 There are two commands to copy text from one buffer to another. The result is
209 that the buffers will be equal within the specified range.
210
211 *:diffg* *:diffget*
212 :[range]diffg[et] [bufspec]
213 Modify the current buffer to undo difference with another
214 buffer. If [bufspec] is given, that buffer is used.
215 Otherwise this only works if there is one other buffer in diff
216 mode.
217 See below for [range].
218
219 *:diffpu* *:diffput*
220 :[range]diffpu[t] [bufspec]
221 Modify another buffer to undo difference with the current
222 buffer. Just like ":diffget" but the other buffer is modified
223 instead of the current one.
224 See below for [range].
225
226 *do*
227 do Same as ":diffget" without argument or range. The "o" stands
228 for "obtain" ("dg" can't be used, it could be the start of
229 "dgg"!).
230
231 *dp*
232 dp Same as ":diffput" without argument or range.
233
234 When no [range] is given, the diff at the cursor position or just above it is
235 affected. When [range] is used, Vim tries to only put or get the specified
236 lines. When there are deleted lines, this may not always be possible.
237
238 There can be deleted lines below the last line of the buffer. When the cursor
239 is on the last line in the buffer and there is no diff above this line, the
240 ":diffget" and "do" commands will obtain lines from the other buffer.
241
242 To be able to get those lines from another buffer in a [range] it's allowed to
243 use the last line number plus one. This command gets all diffs from the other
244 buffer: >
245
246 :1,$+1diffget
247
248 Note that deleted lines are displayed, but not counted as text lines. You
249 can't move the cursor into them. To fill the deleted lines with the lines
250 from another buffer use ":diffget" on the line below them.
251
252 The [bufspec] argument above can be a buffer number, a pattern for a buffer
253 name or a part of a buffer name. Examples:
254
255 :diffget Use the other buffer which is in diff mode
256 :diffget 3 Use buffer 3
257 :diffget v2 Use the buffer which matches "v2" and is in
258 diff mode (e.g., "file.c.v2")
259
260 ==============================================================================
261 5. Diff options *diff-options*
262
263 Also see |'diffopt'| and the "diff" item of |'fillchars'|.
264
265
266 FINDING THE DIFFERENCES *diff-diffexpr*
267
268 The 'diffexpr' option can be set to use something else than the standard
269 "diff" program to compare two files and find the differences.
270
271 When 'diffexpr' is empty, Vim uses this command to find the differences
272 between file1 and file2: >
273
274 diff file1 file2 > outfile
275
276 The ">" is replaced with the value of 'shellredir'.
277
278 The output of "diff" must be a normal "ed" style diff. Do NOT use a context
279 diff. This example explains the format that Vim expects: >
280
281 1a2
282 > bbb
283 4d4
284 < 111
285 7c7
286 < GGG
287 ---
288 > ggg
289
290 The "1a2" item appends the line "bbb".
291 The "4d4" item deletes the line "111".
292 The '7c7" item replaces the line "GGG" with "ggg".
293
294 When 'diffexpr' is not empty, Vim evaluates to obtain a diff file in the
295 format mentioned. These variables are set to the file names used:
296
297 v:fname_in original file
298 v:fname_new new version of the same file
299 v:fname_out resulting diff file
300
301 Additionally, 'diffexpr' should take care of "icase" and "iwhite" in the
302 'diffopt' option. 'diffexpr' cannot change the value of 'lines' and
303 'columns'.
304
305 Example (this does almost the same as 'diffexpr' being empty): >
306
307 set diffexpr=MyDiff()
308 function MyDiff()
309 let opt = ""
310 if &diffopt =~ "icase"
311 let opt = opt . "-i "
312 endif
313 if &diffopt =~ "iwhite"
314 let opt = opt . "-b "
315 endif
316 silent execute "!diff -a --binary " . opt . v:fname_in . " " . v:fname_new .
317 \ " > " . v:fname_out
318 endfunction
319
320 The "-a" argument is used to force comparing the files as text, comparing as
321 binaries isn't useful. The "--binary" argument makes the files read in binary
322 mode, so that a CTRL-Z doesn't end the text on DOS.
323
324 *E97*
325 Vim will do a test if the diff output looks alright. If it doesn't, you will
326 get an error message. Possible causes:
327 - The "diff" program cannot be executed.
328 - The "diff" program doesn't produce normal "ed" style diffs (see above).
329 - The 'shell' and associated options are not set correctly. Try if filtering
330 works with a command like ":!sort".
331 - You are using 'diffexpr' and it doesn't work.
332 If it's not clear what the problem is set the 'verbose' option to see more
333 messages.
334
335
336 USING PATCHES *diff-patchexpr*
337
338 The 'patchexpr' option can be set to use something else than the standard
339 "patch" program.
340
341 When 'patchexpr' is empty, Vim will call the "patch" program like this: >
342
343 patch -o outfile origfile < patchfile
344
345 This should work fine with most versions of the "patch" program. Note that a
346 CR in the middle of a line may cause problems, it is seen as a line break.
347
348 If the default doesn't work for you, set the 'patchexpr' to an expression that
349 will have the same effect. These variables are set to the file names used:
350
351 v:fname_in original file
352 v:fname_diff patch file
353 v:fname_out resulting patched file
354
355 Example (this does the same as 'patchexpr' being empty): >
356
357 let patchexpr=MyPatch
358 function MyPatch
359 :call system("patch -o " . v:fname_out . " " . v:fname_in .
360 \ " < " . v:fname_diff)
361 endfunction
362
363 Make sure that using the "patch" program doesn't have unwanted side effects.
364 For example, watch out for additionally generated files, which should be
365 deleted. It should just patch the file and nothing else.
366 Vim will change directory to "/tmp" or another temp directory before
367 evaluating 'patchexpr'. This hopefully avoids that files in the current
368 directory are accidentally patched. Vim will also delete files starting with
369 v:fname_in and ending in ".rej" and ".orig".
370
371 vim:tw=78:ts=8:ft=help:norl: