Merge branch 'js/maint-am-rebase-invalid-author'
[git/git.git] / Documentation / gitattributes.txt
1 gitattributes(5)
2 ================
3
4 NAME
5 ----
6 gitattributes - defining attributes per path
7
8 SYNOPSIS
9 --------
10 $GIT_DIR/info/attributes, .gitattributes
11
12
13 DESCRIPTION
14 -----------
15
16 A `gitattributes` file is a simple text file that gives
17 `attributes` to pathnames.
18
19 Each line in `gitattributes` file is of form:
20
21 pattern attr1 attr2 ...
22
23 That is, a pattern followed by an attributes list,
24 separated by whitespaces. When the pattern matches the
25 path in question, the attributes listed on the line are given to
26 the path.
27
28 Each attribute can be in one of these states for a given path:
29
30 Set::
31
32 The path has the attribute with special value "true";
33 this is specified by listing only the name of the
34 attribute in the attribute list.
35
36 Unset::
37
38 The path has the attribute with special value "false";
39 this is specified by listing the name of the attribute
40 prefixed with a dash `-` in the attribute list.
41
42 Set to a value::
43
44 The path has the attribute with specified string value;
45 this is specified by listing the name of the attribute
46 followed by an equal sign `=` and its value in the
47 attribute list.
48
49 Unspecified::
50
51 No pattern matches the path, and nothing says if
52 the path has or does not have the attribute, the
53 attribute for the path is said to be Unspecified.
54
55 When more than one pattern matches the path, a later line
56 overrides an earlier line. This overriding is done per
57 attribute. The rules how the pattern matches paths are the
58 same as in `.gitignore` files; see linkgit:gitignore[5].
59
60 When deciding what attributes are assigned to a path, git
61 consults `$GIT_DIR/info/attributes` file (which has the highest
62 precedence), `.gitattributes` file in the same directory as the
63 path in question, and its parent directories up to the toplevel of the
64 work tree (the further the directory that contains `.gitattributes`
65 is from the path in question, the lower its precedence).
66
67 If you wish to affect only a single repository (i.e., to assign
68 attributes to files that are particular to one user's workflow), then
69 attributes should be placed in the `$GIT_DIR/info/attributes` file.
70 Attributes which should be version-controlled and distributed to other
71 repositories (i.e., attributes of interest to all users) should go into
72 `.gitattributes` files.
73
74 Sometimes you would need to override an setting of an attribute
75 for a path to `unspecified` state. This can be done by listing
76 the name of the attribute prefixed with an exclamation point `!`.
77
78
79 EFFECTS
80 -------
81
82 Certain operations by git can be influenced by assigning
83 particular attributes to a path. Currently, the following
84 operations are attributes-aware.
85
86 Checking-out and checking-in
87 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
88
89 These attributes affect how the contents stored in the
90 repository are copied to the working tree files when commands
91 such as 'git checkout' and 'git merge' run. They also affect how
92 git stores the contents you prepare in the working tree in the
93 repository upon 'git add' and 'git commit'.
94
95 `text`
96 ^^^^^^
97
98 This attribute enables and controls end-of-line normalization. When a
99 text file is normalized, its line endings are converted to LF in the
100 repository. To control what line ending style is used in the working
101 directory, use the `eol` attribute for a single file and the
102 `core.eol` configuration variable for all text files.
103
104 Set::
105
106 Setting the `text` attribute on a path enables end-of-line
107 normalization and marks the path as a text file. End-of-line
108 conversion takes place without guessing the content type.
109
110 Unset::
111
112 Unsetting the `text` attribute on a path tells git not to
113 attempt any end-of-line conversion upon checkin or checkout.
114
115 Set to string value "auto"::
116
117 When `text` is set to "auto", the path is marked for automatic
118 end-of-line normalization. If git decides that the content is
119 text, its line endings are normalized to LF on checkin.
120
121 Unspecified::
122
123 If the `text` attribute is unspecified, git uses the
124 `core.autocrlf` configuration variable to determine if the
125 file should be converted.
126
127 Any other value causes git to act as if `text` has been left
128 unspecified.
129
130 `eol`
131 ^^^^^
132
133 This attribute sets a specific line-ending style to be used in the
134 working directory. It enables end-of-line normalization without any
135 content checks, effectively setting the `text` attribute.
136
137 Set to string value "crlf"::
138
139 This setting forces git to normalize line endings for this
140 file on checkin and convert them to CRLF when the file is
141 checked out.
142
143 Set to string value "lf"::
144
145 This setting forces git to normalize line endings to LF on
146 checkin and prevents conversion to CRLF when the file is
147 checked out.
148
149 Backwards compatibility with `crlf` attribute
150 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
151
152 For backwards compatibility, the `crlf` attribute is interpreted as
153 follows:
154
155 ------------------------
156 crlf text
157 -crlf -text
158 crlf=input eol=lf
159 ------------------------
160
161 End-of-line conversion
162 ^^^^^^^^^^^^^^^^^^^^^^
163
164 While git normally leaves file contents alone, it can be configured to
165 normalize line endings to LF in the repository and, optionally, to
166 convert them to CRLF when files are checked out.
167
168 Here is an example that will make git normalize .txt, .vcproj and .sh
169 files, ensure that .vcproj files have CRLF and .sh files have LF in
170 the working directory, and prevent .jpg files from being normalized
171 regardless of their content.
172
173 ------------------------
174 *.txt text
175 *.vcproj eol=crlf
176 *.sh eol=lf
177 *.jpg -text
178 ------------------------
179
180 Other source code management systems normalize all text files in their
181 repositories, and there are two ways to enable similar automatic
182 normalization in git.
183
184 If you simply want to have CRLF line endings in your working directory
185 regardless of the repository you are working with, you can set the
186 config variable "core.autocrlf" without changing any attributes.
187
188 ------------------------
189 [core]
190 autocrlf = true
191 ------------------------
192
193 This does not force normalization of all text files, but does ensure
194 that text files that you introduce to the repository have their line
195 endings normalized to LF when they are added, and that files that are
196 already normalized in the repository stay normalized.
197
198 If you want to interoperate with a source code management system that
199 enforces end-of-line normalization, or you simply want all text files
200 in your repository to be normalized, you should instead set the `text`
201 attribute to "auto" for _all_ files.
202
203 ------------------------
204 * text=auto
205 ------------------------
206
207 This ensures that all files that git considers to be text will have
208 normalized (LF) line endings in the repository. The `core.eol`
209 configuration variable controls which line endings git will use for
210 normalized files in your working directory; the default is to use the
211 native line ending for your platform, or CRLF if `core.autocrlf` is
212 set.
213
214 NOTE: When `text=auto` normalization is enabled in an existing
215 repository, any text files containing CRLFs should be normalized. If
216 they are not they will be normalized the next time someone tries to
217 change them, causing unfortunate misattribution. From a clean working
218 directory:
219
220 -------------------------------------------------
221 $ echo "* text=auto" >>.gitattributes
222 $ rm .git/index # Remove the index to force git to
223 $ git reset # re-scan the working directory
224 $ git status # Show files that will be normalized
225 $ git add -u
226 $ git add .gitattributes
227 $ git commit -m "Introduce end-of-line normalization"
228 -------------------------------------------------
229
230 If any files that should not be normalized show up in 'git status',
231 unset their `text` attribute before running 'git add -u'.
232
233 ------------------------
234 manual.pdf -text
235 ------------------------
236
237 Conversely, text files that git does not detect can have normalization
238 enabled manually.
239
240 ------------------------
241 weirdchars.txt text
242 ------------------------
243
244 If `core.safecrlf` is set to "true" or "warn", git verifies if
245 the conversion is reversible for the current setting of
246 `core.autocrlf`. For "true", git rejects irreversible
247 conversions; for "warn", git only prints a warning but accepts
248 an irreversible conversion. The safety triggers to prevent such
249 a conversion done to the files in the work tree, but there are a
250 few exceptions. Even though...
251
252 - 'git add' itself does not touch the files in the work tree, the
253 next checkout would, so the safety triggers;
254
255 - 'git apply' to update a text file with a patch does touch the files
256 in the work tree, but the operation is about text files and CRLF
257 conversion is about fixing the line ending inconsistencies, so the
258 safety does not trigger;
259
260 - 'git diff' itself does not touch the files in the work tree, it is
261 often run to inspect the changes you intend to next 'git add'. To
262 catch potential problems early, safety triggers.
263
264
265 `ident`
266 ^^^^^^^
267
268 When the attribute `ident` is set for a path, git replaces
269 `$Id$` in the blob object with `$Id:`, followed by the
270 40-character hexadecimal blob object name, followed by a dollar
271 sign `$` upon checkout. Any byte sequence that begins with
272 `$Id:` and ends with `$` in the worktree file is replaced
273 with `$Id$` upon check-in.
274
275
276 `filter`
277 ^^^^^^^^
278
279 A `filter` attribute can be set to a string value that names a
280 filter driver specified in the configuration.
281
282 A filter driver consists of a `clean` command and a `smudge`
283 command, either of which can be left unspecified. Upon
284 checkout, when the `smudge` command is specified, the command is
285 fed the blob object from its standard input, and its standard
286 output is used to update the worktree file. Similarly, the
287 `clean` command is used to convert the contents of worktree file
288 upon checkin.
289
290 A missing filter driver definition in the config is not an error
291 but makes the filter a no-op passthru.
292
293 The content filtering is done to massage the content into a
294 shape that is more convenient for the platform, filesystem, and
295 the user to use. The key phrase here is "more convenient" and not
296 "turning something unusable into usable". In other words, the
297 intent is that if someone unsets the filter driver definition,
298 or does not have the appropriate filter program, the project
299 should still be usable.
300
301 For example, in .gitattributes, you would assign the `filter`
302 attribute for paths.
303
304 ------------------------
305 *.c filter=indent
306 ------------------------
307
308 Then you would define a "filter.indent.clean" and "filter.indent.smudge"
309 configuration in your .git/config to specify a pair of commands to
310 modify the contents of C programs when the source files are checked
311 in ("clean" is run) and checked out (no change is made because the
312 command is "cat").
313
314 ------------------------
315 [filter "indent"]
316 clean = indent
317 smudge = cat
318 ------------------------
319
320
321 Interaction between checkin/checkout attributes
322 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
323
324 In the check-in codepath, the worktree file is first converted
325 with `filter` driver (if specified and corresponding driver
326 defined), then the result is processed with `ident` (if
327 specified), and then finally with `text` (again, if specified
328 and applicable).
329
330 In the check-out codepath, the blob content is first converted
331 with `text`, and then `ident` and fed to `filter`.
332
333
334 Generating diff text
335 ~~~~~~~~~~~~~~~~~~~~
336
337 `diff`
338 ^^^^^^
339
340 The attribute `diff` affects how 'git' generates diffs for particular
341 files. It can tell git whether to generate a textual patch for the path
342 or to treat the path as a binary file. It can also affect what line is
343 shown on the hunk header `@@ -k,l +n,m @@` line, tell git to use an
344 external command to generate the diff, or ask git to convert binary
345 files to a text format before generating the diff.
346
347 Set::
348
349 A path to which the `diff` attribute is set is treated
350 as text, even when they contain byte values that
351 normally never appear in text files, such as NUL.
352
353 Unset::
354
355 A path to which the `diff` attribute is unset will
356 generate `Binary files differ` (or a binary patch, if
357 binary patches are enabled).
358
359 Unspecified::
360
361 A path to which the `diff` attribute is unspecified
362 first gets its contents inspected, and if it looks like
363 text, it is treated as text. Otherwise it would
364 generate `Binary files differ`.
365
366 String::
367
368 Diff is shown using the specified diff driver. Each driver may
369 specify one or more options, as described in the following
370 section. The options for the diff driver "foo" are defined
371 by the configuration variables in the "diff.foo" section of the
372 git config file.
373
374
375 Defining an external diff driver
376 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
377
378 The definition of a diff driver is done in `gitconfig`, not
379 `gitattributes` file, so strictly speaking this manual page is a
380 wrong place to talk about it. However...
381
382 To define an external diff driver `jcdiff`, add a section to your
383 `$GIT_DIR/config` file (or `$HOME/.gitconfig` file) like this:
384
385 ----------------------------------------------------------------
386 [diff "jcdiff"]
387 command = j-c-diff
388 ----------------------------------------------------------------
389
390 When git needs to show you a diff for the path with `diff`
391 attribute set to `jcdiff`, it calls the command you specified
392 with the above configuration, i.e. `j-c-diff`, with 7
393 parameters, just like `GIT_EXTERNAL_DIFF` program is called.
394 See linkgit:git[1] for details.
395
396
397 Defining a custom hunk-header
398 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
399
400 Each group of changes (called a "hunk") in the textual diff output
401 is prefixed with a line of the form:
402
403 @@ -k,l +n,m @@ TEXT
404
405 This is called a 'hunk header'. The "TEXT" portion is by default a line
406 that begins with an alphabet, an underscore or a dollar sign; this
407 matches what GNU 'diff -p' output uses. This default selection however
408 is not suited for some contents, and you can use a customized pattern
409 to make a selection.
410
411 First, in .gitattributes, you would assign the `diff` attribute
412 for paths.
413
414 ------------------------
415 *.tex diff=tex
416 ------------------------
417
418 Then, you would define a "diff.tex.xfuncname" configuration to
419 specify a regular expression that matches a line that you would
420 want to appear as the hunk header "TEXT". Add a section to your
421 `$GIT_DIR/config` file (or `$HOME/.gitconfig` file) like this:
422
423 ------------------------
424 [diff "tex"]
425 xfuncname = "^(\\\\(sub)*section\\{.*)$"
426 ------------------------
427
428 Note. A single level of backslashes are eaten by the
429 configuration file parser, so you would need to double the
430 backslashes; the pattern above picks a line that begins with a
431 backslash, and zero or more occurrences of `sub` followed by
432 `section` followed by open brace, to the end of line.
433
434 There are a few built-in patterns to make this easier, and `tex`
435 is one of them, so you do not have to write the above in your
436 configuration file (you still need to enable this with the
437 attribute mechanism, via `.gitattributes`). The following built in
438 patterns are available:
439
440 - `bibtex` suitable for files with BibTeX coded references.
441
442 - `cpp` suitable for source code in the C and C++ languages.
443
444 - `html` suitable for HTML/XHTML documents.
445
446 - `java` suitable for source code in the Java language.
447
448 - `objc` suitable for source code in the Objective-C language.
449
450 - `pascal` suitable for source code in the Pascal/Delphi language.
451
452 - `php` suitable for source code in the PHP language.
453
454 - `python` suitable for source code in the Python language.
455
456 - `ruby` suitable for source code in the Ruby language.
457
458 - `tex` suitable for source code for LaTeX documents.
459
460
461 Customizing word diff
462 ^^^^^^^^^^^^^^^^^^^^^
463
464 You can customize the rules that `git diff --word-diff` uses to
465 split words in a line, by specifying an appropriate regular expression
466 in the "diff.*.wordRegex" configuration variable. For example, in TeX
467 a backslash followed by a sequence of letters forms a command, but
468 several such commands can be run together without intervening
469 whitespace. To separate them, use a regular expression in your
470 `$GIT_DIR/config` file (or `$HOME/.gitconfig` file) like this:
471
472 ------------------------
473 [diff "tex"]
474 wordRegex = "\\\\[a-zA-Z]+|[{}]|\\\\.|[^\\{}[:space:]]+"
475 ------------------------
476
477 A built-in pattern is provided for all languages listed in the
478 previous section.
479
480
481 Performing text diffs of binary files
482 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
483
484 Sometimes it is desirable to see the diff of a text-converted
485 version of some binary files. For example, a word processor
486 document can be converted to an ASCII text representation, and
487 the diff of the text shown. Even though this conversion loses
488 some information, the resulting diff is useful for human
489 viewing (but cannot be applied directly).
490
491 The `textconv` config option is used to define a program for
492 performing such a conversion. The program should take a single
493 argument, the name of a file to convert, and produce the
494 resulting text on stdout.
495
496 For example, to show the diff of the exif information of a
497 file instead of the binary information (assuming you have the
498 exif tool installed), add the following section to your
499 `$GIT_DIR/config` file (or `$HOME/.gitconfig` file):
500
501 ------------------------
502 [diff "jpg"]
503 textconv = exif
504 ------------------------
505
506 NOTE: The text conversion is generally a one-way conversion;
507 in this example, we lose the actual image contents and focus
508 just on the text data. This means that diffs generated by
509 textconv are _not_ suitable for applying. For this reason,
510 only `git diff` and the `git log` family of commands (i.e.,
511 log, whatchanged, show) will perform text conversion. `git
512 format-patch` will never generate this output. If you want to
513 send somebody a text-converted diff of a binary file (e.g.,
514 because it quickly conveys the changes you have made), you
515 should generate it separately and send it as a comment _in
516 addition to_ the usual binary diff that you might send.
517
518 Because text conversion can be slow, especially when doing a
519 large number of them with `git log -p`, git provides a mechanism
520 to cache the output and use it in future diffs. To enable
521 caching, set the "cachetextconv" variable in your diff driver's
522 config. For example:
523
524 ------------------------
525 [diff "jpg"]
526 textconv = exif
527 cachetextconv = true
528 ------------------------
529
530 This will cache the result of running "exif" on each blob
531 indefinitely. If you change the textconv config variable for a
532 diff driver, git will automatically invalidate the cache entries
533 and re-run the textconv filter. If you want to invalidate the
534 cache manually (e.g., because your version of "exif" was updated
535 and now produces better output), you can remove the cache
536 manually with `git update-ref -d refs/notes/textconv/jpg` (where
537 "jpg" is the name of the diff driver, as in the example above).
538
539 Performing a three-way merge
540 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
541
542 `merge`
543 ^^^^^^^
544
545 The attribute `merge` affects how three versions of a file is
546 merged when a file-level merge is necessary during `git merge`,
547 and other commands such as `git revert` and `git cherry-pick`.
548
549 Set::
550
551 Built-in 3-way merge driver is used to merge the
552 contents in a way similar to 'merge' command of `RCS`
553 suite. This is suitable for ordinary text files.
554
555 Unset::
556
557 Take the version from the current branch as the
558 tentative merge result, and declare that the merge has
559 conflicts. This is suitable for binary files that does
560 not have a well-defined merge semantics.
561
562 Unspecified::
563
564 By default, this uses the same built-in 3-way merge
565 driver as is the case the `merge` attribute is set.
566 However, `merge.default` configuration variable can name
567 different merge driver to be used for paths to which the
568 `merge` attribute is unspecified.
569
570 String::
571
572 3-way merge is performed using the specified custom
573 merge driver. The built-in 3-way merge driver can be
574 explicitly specified by asking for "text" driver; the
575 built-in "take the current branch" driver can be
576 requested with "binary".
577
578
579 Built-in merge drivers
580 ^^^^^^^^^^^^^^^^^^^^^^
581
582 There are a few built-in low-level merge drivers defined that
583 can be asked for via the `merge` attribute.
584
585 text::
586
587 Usual 3-way file level merge for text files. Conflicted
588 regions are marked with conflict markers `<<<<<<<`,
589 `=======` and `>>>>>>>`. The version from your branch
590 appears before the `=======` marker, and the version
591 from the merged branch appears after the `=======`
592 marker.
593
594 binary::
595
596 Keep the version from your branch in the work tree, but
597 leave the path in the conflicted state for the user to
598 sort out.
599
600 union::
601
602 Run 3-way file level merge for text files, but take
603 lines from both versions, instead of leaving conflict
604 markers. This tends to leave the added lines in the
605 resulting file in random order and the user should
606 verify the result. Do not use this if you do not
607 understand the implications.
608
609
610 Defining a custom merge driver
611 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
612
613 The definition of a merge driver is done in the `.git/config`
614 file, not in the `gitattributes` file, so strictly speaking this
615 manual page is a wrong place to talk about it. However...
616
617 To define a custom merge driver `filfre`, add a section to your
618 `$GIT_DIR/config` file (or `$HOME/.gitconfig` file) like this:
619
620 ----------------------------------------------------------------
621 [merge "filfre"]
622 name = feel-free merge driver
623 driver = filfre %O %A %B
624 recursive = binary
625 ----------------------------------------------------------------
626
627 The `merge.*.name` variable gives the driver a human-readable
628 name.
629
630 The `merge.*.driver` variable's value is used to construct a
631 command to run to merge ancestor's version (`%O`), current
632 version (`%A`) and the other branches' version (`%B`). These
633 three tokens are replaced with the names of temporary files that
634 hold the contents of these versions when the command line is
635 built. Additionally, %L will be replaced with the conflict marker
636 size (see below).
637
638 The merge driver is expected to leave the result of the merge in
639 the file named with `%A` by overwriting it, and exit with zero
640 status if it managed to merge them cleanly, or non-zero if there
641 were conflicts.
642
643 The `merge.*.recursive` variable specifies what other merge
644 driver to use when the merge driver is called for an internal
645 merge between common ancestors, when there are more than one.
646 When left unspecified, the driver itself is used for both
647 internal merge and the final merge.
648
649
650 `conflict-marker-size`
651 ^^^^^^^^^^^^^^^^^^^^^^
652
653 This attribute controls the length of conflict markers left in
654 the work tree file during a conflicted merge. Only setting to
655 the value to a positive integer has any meaningful effect.
656
657 For example, this line in `.gitattributes` can be used to tell the merge
658 machinery to leave much longer (instead of the usual 7-character-long)
659 conflict markers when merging the file `Documentation/git-merge.txt`
660 results in a conflict.
661
662 ------------------------
663 Documentation/git-merge.txt conflict-marker-size=32
664 ------------------------
665
666
667 Checking whitespace errors
668 ~~~~~~~~~~~~~~~~~~~~~~~~~~
669
670 `whitespace`
671 ^^^^^^^^^^^^
672
673 The `core.whitespace` configuration variable allows you to define what
674 'diff' and 'apply' should consider whitespace errors for all paths in
675 the project (See linkgit:git-config[1]). This attribute gives you finer
676 control per path.
677
678 Set::
679
680 Notice all types of potential whitespace errors known to git.
681
682 Unset::
683
684 Do not notice anything as error.
685
686 Unspecified::
687
688 Use the value of `core.whitespace` configuration variable to
689 decide what to notice as error.
690
691 String::
692
693 Specify a comma separate list of common whitespace problems to
694 notice in the same format as `core.whitespace` configuration
695 variable.
696
697
698 Creating an archive
699 ~~~~~~~~~~~~~~~~~~~
700
701 `export-ignore`
702 ^^^^^^^^^^^^^^^
703
704 Files and directories with the attribute `export-ignore` won't be added to
705 archive files.
706
707 `export-subst`
708 ^^^^^^^^^^^^^^
709
710 If the attribute `export-subst` is set for a file then git will expand
711 several placeholders when adding this file to an archive. The
712 expansion depends on the availability of a commit ID, i.e., if
713 linkgit:git-archive[1] has been given a tree instead of a commit or a
714 tag then no replacement will be done. The placeholders are the same
715 as those for the option `--pretty=format:` of linkgit:git-log[1],
716 except that they need to be wrapped like this: `$Format:PLACEHOLDERS$`
717 in the file. E.g. the string `$Format:%H$` will be replaced by the
718 commit hash.
719
720
721 Packing objects
722 ~~~~~~~~~~~~~~~
723
724 `delta`
725 ^^^^^^^
726
727 Delta compression will not be attempted for blobs for paths with the
728 attribute `delta` set to false.
729
730
731 Viewing files in GUI tools
732 ~~~~~~~~~~~~~~~~~~~~~~~~~~
733
734 `encoding`
735 ^^^^^^^^^^
736
737 The value of this attribute specifies the character encoding that should
738 be used by GUI tools (e.g. linkgit:gitk[1] and linkgit:git-gui[1]) to
739 display the contents of the relevant file. Note that due to performance
740 considerations linkgit:gitk[1] does not use this attribute unless you
741 manually enable per-file encodings in its options.
742
743 If this attribute is not set or has an invalid value, the value of the
744 `gui.encoding` configuration variable is used instead
745 (See linkgit:git-config[1]).
746
747
748 USING ATTRIBUTE MACROS
749 ----------------------
750
751 You do not want any end-of-line conversions applied to, nor textual diffs
752 produced for, any binary file you track. You would need to specify e.g.
753
754 ------------
755 *.jpg -text -diff
756 ------------
757
758 but that may become cumbersome, when you have many attributes. Using
759 attribute macros, you can specify groups of attributes set or unset at
760 the same time. The system knows a built-in attribute macro, `binary`:
761
762 ------------
763 *.jpg binary
764 ------------
765
766 which is equivalent to the above. Note that the attribute macros can only
767 be "Set" (see the above example that sets "binary" macro as if it were an
768 ordinary attribute --- setting it in turn unsets "text" and "diff").
769
770
771 DEFINING ATTRIBUTE MACROS
772 -------------------------
773
774 Custom attribute macros can be defined only in the `.gitattributes` file
775 at the toplevel (i.e. not in any subdirectory). The built-in attribute
776 macro "binary" is equivalent to:
777
778 ------------
779 [attr]binary -diff -text
780 ------------
781
782
783 EXAMPLE
784 -------
785
786 If you have these three `gitattributes` file:
787
788 ----------------------------------------------------------------
789 (in $GIT_DIR/info/attributes)
790
791 a* foo !bar -baz
792
793 (in .gitattributes)
794 abc foo bar baz
795
796 (in t/.gitattributes)
797 ab* merge=filfre
798 abc -foo -bar
799 *.c frotz
800 ----------------------------------------------------------------
801
802 the attributes given to path `t/abc` are computed as follows:
803
804 1. By examining `t/.gitattributes` (which is in the same
805 directory as the path in question), git finds that the first
806 line matches. `merge` attribute is set. It also finds that
807 the second line matches, and attributes `foo` and `bar`
808 are unset.
809
810 2. Then it examines `.gitattributes` (which is in the parent
811 directory), and finds that the first line matches, but
812 `t/.gitattributes` file already decided how `merge`, `foo`
813 and `bar` attributes should be given to this path, so it
814 leaves `foo` and `bar` unset. Attribute `baz` is set.
815
816 3. Finally it examines `$GIT_DIR/info/attributes`. This file
817 is used to override the in-tree settings. The first line is
818 a match, and `foo` is set, `bar` is reverted to unspecified
819 state, and `baz` is unset.
820
821 As the result, the attributes assignment to `t/abc` becomes:
822
823 ----------------------------------------------------------------
824 foo set to true
825 bar unspecified
826 baz set to false
827 merge set to string value "filfre"
828 frotz unspecified
829 ----------------------------------------------------------------
830
831
832
833 GIT
834 ---
835 Part of the linkgit:git[1] suite