1GITATTRIBUTES(5)                  Git Manual                  GITATTRIBUTES(5)
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NAME

6       gitattributes - Defining attributes per path
7

SYNOPSIS

9       $GIT_DIR/info/attributes, .gitattributes
10

DESCRIPTION

12       A gitattributes file is a simple text file that gives attributes to
13       pathnames.
14
15       Each line in gitattributes file is of form:
16
17           pattern attr1 attr2 ...
18
19       That is, a pattern followed by an attributes list, separated by
20       whitespaces. Leading and trailing whitespaces are ignored. Lines that
21       begin with # are ignored. Patterns that begin with a double quote are
22       quoted in C style. When the pattern matches the path in question, the
23       attributes listed on the line are given to the path.
24
25       Each attribute can be in one of these states for a given path:
26
27       Set
28           The path has the attribute with special value "true"; this is
29           specified by listing only the name of the attribute in the
30           attribute list.
31
32       Unset
33           The path has the attribute with special value "false"; this is
34           specified by listing the name of the attribute prefixed with a dash
35           - in the attribute list.
36
37       Set to a value
38           The path has the attribute with specified string value; this is
39           specified by listing the name of the attribute followed by an equal
40           sign = and its value in the attribute list.
41
42       Unspecified
43           No pattern matches the path, and nothing says if the path has or
44           does not have the attribute, the attribute for the path is said to
45           be Unspecified.
46
47       When more than one pattern matches the path, a later line overrides an
48       earlier line. This overriding is done per attribute.
49
50       The rules by which the pattern matches paths are the same as in
51       .gitignore files (see gitignore(5)), with a few exceptions:
52
53       •   negative patterns are forbidden
54
55       •   patterns that match a directory do not recursively match paths
56           inside that directory (so using the trailing-slash path/ syntax is
57           pointless in an attributes file; use path/** instead)
58
59       When deciding what attributes are assigned to a path, Git consults
60       $GIT_DIR/info/attributes file (which has the highest precedence),
61       .gitattributes file in the same directory as the path in question, and
62       its parent directories up to the toplevel of the work tree (the further
63       the directory that contains .gitattributes is from the path in
64       question, the lower its precedence). Finally global and system-wide
65       files are considered (they have the lowest precedence).
66
67       When the .gitattributes file is missing from the work tree, the path in
68       the index is used as a fall-back. During checkout process,
69       .gitattributes in the index is used and then the file in the working
70       tree is used as a fall-back.
71
72       If you wish to affect only a single repository (i.e., to assign
73       attributes to files that are particular to one user’s workflow for that
74       repository), then attributes should be placed in the
75       $GIT_DIR/info/attributes file. Attributes which should be
76       version-controlled and distributed to other repositories (i.e.,
77       attributes of interest to all users) should go into .gitattributes
78       files. Attributes that should affect all repositories for a single user
79       should be placed in a file specified by the core.attributesFile
80       configuration option (see git-config(1)). Its default value is
81       $XDG_CONFIG_HOME/git/attributes. If $XDG_CONFIG_HOME is either not set
82       or empty, $HOME/.config/git/attributes is used instead. Attributes for
83       all users on a system should be placed in the
84       $(prefix)/etc/gitattributes file.
85
86       Sometimes you would need to override a setting of an attribute for a
87       path to Unspecified state. This can be done by listing the name of the
88       attribute prefixed with an exclamation point !.
89

EFFECTS

91       Certain operations by Git can be influenced by assigning particular
92       attributes to a path. Currently, the following operations are
93       attributes-aware.
94
95   Checking-out and checking-in
96       These attributes affect how the contents stored in the repository are
97       copied to the working tree files when commands such as git switch, git
98       checkout and git merge run. They also affect how Git stores the
99       contents you prepare in the working tree in the repository upon git add
100       and git commit.
101
102       text
103           This attribute enables and controls end-of-line normalization. When
104           a text file is normalized, its line endings are converted to LF in
105           the repository. To control what line ending style is used in the
106           working directory, use the eol attribute for a single file and the
107           core.eol configuration variable for all text files. Note that
108           setting core.autocrlf to true or input overrides core.eol (see the
109           definitions of those options in git-config(1)).
110
111           Set
112               Setting the text attribute on a path enables end-of-line
113               normalization and marks the path as a text file. End-of-line
114               conversion takes place without guessing the content type.
115
116           Unset
117               Unsetting the text attribute on a path tells Git not to attempt
118               any end-of-line conversion upon checkin or checkout.
119
120           Set to string value "auto"
121               When text is set to "auto", the path is marked for automatic
122               end-of-line conversion. If Git decides that the content is
123               text, its line endings are converted to LF on checkin. When the
124               file has been committed with CRLF, no conversion is done.
125
126           Unspecified
127               If the text attribute is unspecified, Git uses the
128               core.autocrlf configuration variable to determine if the file
129               should be converted.
130
131           Any other value causes Git to act as if text has been left
132           unspecified.
133
134       eol
135           This attribute sets a specific line-ending style to be used in the
136           working directory. It enables end-of-line conversion without any
137           content checks, effectively setting the text attribute. Note that
138           setting this attribute on paths which are in the index with CRLF
139           line endings may make the paths to be considered dirty. Adding the
140           path to the index again will normalize the line endings in the
141           index.
142
143           Set to string value "crlf"
144               This setting forces Git to normalize line endings for this file
145               on checkin and convert them to CRLF when the file is checked
146               out.
147
148           Set to string value "lf"
149               This setting forces Git to normalize line endings to LF on
150               checkin and prevents conversion to CRLF when the file is
151               checked out.
152
153       Backwards compatibility with crlf attribute
154           For backwards compatibility, the crlf attribute is interpreted as
155           follows:
156
157               crlf            text
158               -crlf           -text
159               crlf=input      eol=lf
160
161       End-of-line conversion
162           While Git normally leaves file contents alone, it can be configured
163           to normalize line endings to LF in the repository and, optionally,
164           to convert them to CRLF when files are checked out.
165
166           If you simply want to have CRLF line endings in your working
167           directory regardless of the repository you are working with, you
168           can set the config variable "core.autocrlf" without using any
169           attributes.
170
171               [core]
172                       autocrlf = true
173
174           This does not force normalization of text files, but does ensure
175           that text files that you introduce to the repository have their
176           line endings normalized to LF when they are added, and that files
177           that are already normalized in the repository stay normalized.
178
179           If you want to ensure that text files that any contributor
180           introduces to the repository have their line endings normalized,
181           you can set the text attribute to "auto" for all files.
182
183               *       text=auto
184
185           The attributes allow a fine-grained control, how the line endings
186           are converted. Here is an example that will make Git normalize
187           .txt, .vcproj and .sh files, ensure that .vcproj files have CRLF
188           and .sh files have LF in the working directory, and prevent .jpg
189           files from being normalized regardless of their content.
190
191               *               text=auto
192               *.txt           text
193               *.vcproj        text eol=crlf
194               *.sh            text eol=lf
195               *.jpg           -text
196
197
198               Note
199               When text=auto conversion is enabled in a cross-platform
200               project using push and pull to a central repository the text
201               files containing CRLFs should be normalized.
202
203           From a clean working directory:
204
205               $ echo "* text=auto" >.gitattributes
206               $ git add --renormalize .
207               $ git status        # Show files that will be normalized
208               $ git commit -m "Introduce end-of-line normalization"
209
210           If any files that should not be normalized show up in git status,
211           unset their text attribute before running git add -u.
212
213               manual.pdf      -text
214
215           Conversely, text files that Git does not detect can have
216           normalization enabled manually.
217
218               weirdchars.txt  text
219
220           If core.safecrlf is set to "true" or "warn", Git verifies if the
221           conversion is reversible for the current setting of core.autocrlf.
222           For "true", Git rejects irreversible conversions; for "warn", Git
223           only prints a warning but accepts an irreversible conversion. The
224           safety triggers to prevent such a conversion done to the files in
225           the work tree, but there are a few exceptions. Even though...
226
227git add itself does not touch the files in the work tree, the
228               next checkout would, so the safety triggers;
229
230git apply to update a text file with a patch does touch the
231               files in the work tree, but the operation is about text files
232               and CRLF conversion is about fixing the line ending
233               inconsistencies, so the safety does not trigger;
234
235git diff itself does not touch the files in the work tree, it
236               is often run to inspect the changes you intend to next git add.
237               To catch potential problems early, safety triggers.
238
239       working-tree-encoding
240           Git recognizes files encoded in ASCII or one of its supersets (e.g.
241           UTF-8, ISO-8859-1, ...) as text files. Files encoded in certain
242           other encodings (e.g. UTF-16) are interpreted as binary and
243           consequently built-in Git text processing tools (e.g. git diff) as
244           well as most Git web front ends do not visualize the contents of
245           these files by default.
246
247           In these cases you can tell Git the encoding of a file in the
248           working directory with the working-tree-encoding attribute. If a
249           file with this attribute is added to Git, then Git re-encodes the
250           content from the specified encoding to UTF-8. Finally, Git stores
251           the UTF-8 encoded content in its internal data structure (called
252           "the index"). On checkout the content is re-encoded back to the
253           specified encoding.
254
255           Please note that using the working-tree-encoding attribute may have
256           a number of pitfalls:
257
258           •   Alternative Git implementations (e.g. JGit or libgit2) and
259               older Git versions (as of March 2018) do not support the
260               working-tree-encoding attribute. If you decide to use the
261               working-tree-encoding attribute in your repository, then it is
262               strongly recommended to ensure that all clients working with
263               the repository support it.
264
265               For example, Microsoft Visual Studio resources files (*.rc) or
266               PowerShell script files (*.ps1) are sometimes encoded in
267               UTF-16. If you declare *.ps1 as files as UTF-16 and you add
268               foo.ps1 with a working-tree-encoding enabled Git client, then
269               foo.ps1 will be stored as UTF-8 internally. A client without
270               working-tree-encoding support will checkout foo.ps1 as UTF-8
271               encoded file. This will typically cause trouble for the users
272               of this file.
273
274               If a Git client that does not support the working-tree-encoding
275               attribute adds a new file bar.ps1, then bar.ps1 will be stored
276               "as-is" internally (in this example probably as UTF-16). A
277               client with working-tree-encoding support will interpret the
278               internal contents as UTF-8 and try to convert it to UTF-16 on
279               checkout. That operation will fail and cause an error.
280
281           •   Reencoding content to non-UTF encodings can cause errors as the
282               conversion might not be UTF-8 round trip safe. If you suspect
283               your encoding to not be round trip safe, then add it to
284               core.checkRoundtripEncoding to make Git check the round trip
285               encoding (see git-config(1)). SHIFT-JIS (Japanese character
286               set) is known to have round trip issues with UTF-8 and is
287               checked by default.
288
289           •   Reencoding content requires resources that might slow down
290               certain Git operations (e.g git checkout or git add).
291
292           Use the working-tree-encoding attribute only if you cannot store a
293           file in UTF-8 encoding and if you want Git to be able to process
294           the content as text.
295
296           As an example, use the following attributes if your *.ps1 files are
297           UTF-16 encoded with byte order mark (BOM) and you want Git to
298           perform automatic line ending conversion based on your platform.
299
300               *.ps1           text working-tree-encoding=UTF-16
301
302           Use the following attributes if your *.ps1 files are UTF-16 little
303           endian encoded without BOM and you want Git to use Windows line
304           endings in the working directory (use UTF-16LE-BOM instead of
305           UTF-16LE if you want UTF-16 little endian with BOM). Please note,
306           it is highly recommended to explicitly define the line endings with
307           eol if the working-tree-encoding attribute is used to avoid
308           ambiguity.
309
310               *.ps1           text working-tree-encoding=UTF-16LE eol=CRLF
311
312           You can get a list of all available encodings on your platform with
313           the following command:
314
315               iconv --list
316
317           If you do not know the encoding of a file, then you can use the
318           file command to guess the encoding:
319
320               file foo.ps1
321
322       ident
323           When the attribute ident is set for a path, Git replaces $Id$ in
324           the blob object with $Id:, followed by the 40-character hexadecimal
325           blob object name, followed by a dollar sign $ upon checkout. Any
326           byte sequence that begins with $Id: and ends with $ in the worktree
327           file is replaced with $Id$ upon check-in.
328
329       filter
330           A filter attribute can be set to a string value that names a filter
331           driver specified in the configuration.
332
333           A filter driver consists of a clean command and a smudge command,
334           either of which can be left unspecified. Upon checkout, when the
335           smudge command is specified, the command is fed the blob object
336           from its standard input, and its standard output is used to update
337           the worktree file. Similarly, the clean command is used to convert
338           the contents of worktree file upon checkin. By default these
339           commands process only a single blob and terminate. If a long
340           running process filter is used in place of clean and/or smudge
341           filters, then Git can process all blobs with a single filter
342           command invocation for the entire life of a single Git command, for
343           example git add --all. If a long running process filter is
344           configured then it always takes precedence over a configured single
345           blob filter. See section below for the description of the protocol
346           used to communicate with a process filter.
347
348           One use of the content filtering is to massage the content into a
349           shape that is more convenient for the platform, filesystem, and the
350           user to use. For this mode of operation, the key phrase here is
351           "more convenient" and not "turning something unusable into usable".
352           In other words, the intent is that if someone unsets the filter
353           driver definition, or does not have the appropriate filter program,
354           the project should still be usable.
355
356           Another use of the content filtering is to store the content that
357           cannot be directly used in the repository (e.g. a UUID that refers
358           to the true content stored outside Git, or an encrypted content)
359           and turn it into a usable form upon checkout (e.g. download the
360           external content, or decrypt the encrypted content).
361
362           These two filters behave differently, and by default, a filter is
363           taken as the former, massaging the contents into more convenient
364           shape. A missing filter driver definition in the config, or a
365           filter driver that exits with a non-zero status, is not an error
366           but makes the filter a no-op passthru.
367
368           You can declare that a filter turns a content that by itself is
369           unusable into a usable content by setting the
370           filter.<driver>.required configuration variable to true.
371
372           Note: Whenever the clean filter is changed, the repo should be
373           renormalized: $ git add --renormalize .
374
375           For example, in .gitattributes, you would assign the filter
376           attribute for paths.
377
378               *.c     filter=indent
379
380           Then you would define a "filter.indent.clean" and
381           "filter.indent.smudge" configuration in your .git/config to specify
382           a pair of commands to modify the contents of C programs when the
383           source files are checked in ("clean" is run) and checked out (no
384           change is made because the command is "cat").
385
386               [filter "indent"]
387                       clean = indent
388                       smudge = cat
389
390           For best results, clean should not alter its output further if it
391           is run twice ("clean→clean" should be equivalent to "clean"), and
392           multiple smudge commands should not alter clean's output
393           ("smudge→smudge→clean" should be equivalent to "clean"). See the
394           section on merging below.
395
396           The "indent" filter is well-behaved in this regard: it will not
397           modify input that is already correctly indented. In this case, the
398           lack of a smudge filter means that the clean filter must accept its
399           own output without modifying it.
400
401           If a filter must succeed in order to make the stored contents
402           usable, you can declare that the filter is required, in the
403           configuration:
404
405               [filter "crypt"]
406                       clean = openssl enc ...
407                       smudge = openssl enc -d ...
408                       required
409
410           Sequence "%f" on the filter command line is replaced with the name
411           of the file the filter is working on. A filter might use this in
412           keyword substitution. For example:
413
414               [filter "p4"]
415                       clean = git-p4-filter --clean %f
416                       smudge = git-p4-filter --smudge %f
417
418           Note that "%f" is the name of the path that is being worked on.
419           Depending on the version that is being filtered, the corresponding
420           file on disk may not exist, or may have different contents. So,
421           smudge and clean commands should not try to access the file on
422           disk, but only act as filters on the content provided to them on
423           standard input.
424
425       Long Running Filter Process
426           If the filter command (a string value) is defined via
427           filter.<driver>.process then Git can process all blobs with a
428           single filter invocation for the entire life of a single Git
429           command. This is achieved by using the long-running process
430           protocol (described in
431           technical/long-running-process-protocol.txt).
432
433           When Git encounters the first file that needs to be cleaned or
434           smudged, it starts the filter and performs the handshake. In the
435           handshake, the welcome message sent by Git is "git-filter-client",
436           only version 2 is supported, and the supported capabilities are
437           "clean", "smudge", and "delay".
438
439           Afterwards Git sends a list of "key=value" pairs terminated with a
440           flush packet. The list will contain at least the filter command
441           (based on the supported capabilities) and the pathname of the file
442           to filter relative to the repository root. Right after the flush
443           packet Git sends the content split in zero or more pkt-line packets
444           and a flush packet to terminate content. Please note, that the
445           filter must not send any response before it received the content
446           and the final flush packet. Also note that the "value" of a
447           "key=value" pair can contain the "=" character whereas the key
448           would never contain that character.
449
450               packet:          git> command=smudge
451               packet:          git> pathname=path/testfile.dat
452               packet:          git> 0000
453               packet:          git> CONTENT
454               packet:          git> 0000
455
456           The filter is expected to respond with a list of "key=value" pairs
457           terminated with a flush packet. If the filter does not experience
458           problems then the list must contain a "success" status. Right after
459           these packets the filter is expected to send the content in zero or
460           more pkt-line packets and a flush packet at the end. Finally, a
461           second list of "key=value" pairs terminated with a flush packet is
462           expected. The filter can change the status in the second list or
463           keep the status as is with an empty list. Please note that the
464           empty list must be terminated with a flush packet regardless.
465
466               packet:          git< status=success
467               packet:          git< 0000
468               packet:          git< SMUDGED_CONTENT
469               packet:          git< 0000
470               packet:          git< 0000  # empty list, keep "status=success" unchanged!
471
472           If the result content is empty then the filter is expected to
473           respond with a "success" status and a flush packet to signal the
474           empty content.
475
476               packet:          git< status=success
477               packet:          git< 0000
478               packet:          git< 0000  # empty content!
479               packet:          git< 0000  # empty list, keep "status=success" unchanged!
480
481           In case the filter cannot or does not want to process the content,
482           it is expected to respond with an "error" status.
483
484               packet:          git< status=error
485               packet:          git< 0000
486
487           If the filter experiences an error during processing, then it can
488           send the status "error" after the content was (partially or
489           completely) sent.
490
491               packet:          git< status=success
492               packet:          git< 0000
493               packet:          git< HALF_WRITTEN_ERRONEOUS_CONTENT
494               packet:          git< 0000
495               packet:          git< status=error
496               packet:          git< 0000
497
498           In case the filter cannot or does not want to process the content
499           as well as any future content for the lifetime of the Git process,
500           then it is expected to respond with an "abort" status at any point
501           in the protocol.
502
503               packet:          git< status=abort
504               packet:          git< 0000
505
506           Git neither stops nor restarts the filter process in case the
507           "error"/"abort" status is set. However, Git sets its exit code
508           according to the filter.<driver>.required flag, mimicking the
509           behavior of the filter.<driver>.clean / filter.<driver>.smudge
510           mechanism.
511
512           If the filter dies during the communication or does not adhere to
513           the protocol then Git will stop the filter process and restart it
514           with the next file that needs to be processed. Depending on the
515           filter.<driver>.required flag Git will interpret that as error.
516
517       Delay
518           If the filter supports the "delay" capability, then Git can send
519           the flag "can-delay" after the filter command and pathname. This
520           flag denotes that the filter can delay filtering the current blob
521           (e.g. to compensate network latencies) by responding with no
522           content but with the status "delayed" and a flush packet.
523
524               packet:          git> command=smudge
525               packet:          git> pathname=path/testfile.dat
526               packet:          git> can-delay=1
527               packet:          git> 0000
528               packet:          git> CONTENT
529               packet:          git> 0000
530               packet:          git< status=delayed
531               packet:          git< 0000
532
533           If the filter supports the "delay" capability then it must support
534           the "list_available_blobs" command. If Git sends this command, then
535           the filter is expected to return a list of pathnames representing
536           blobs that have been delayed earlier and are now available. The
537           list must be terminated with a flush packet followed by a "success"
538           status that is also terminated with a flush packet. If no blobs for
539           the delayed paths are available, yet, then the filter is expected
540           to block the response until at least one blob becomes available.
541           The filter can tell Git that it has no more delayed blobs by
542           sending an empty list. As soon as the filter responds with an empty
543           list, Git stops asking. All blobs that Git has not received at this
544           point are considered missing and will result in an error.
545
546               packet:          git> command=list_available_blobs
547               packet:          git> 0000
548               packet:          git< pathname=path/testfile.dat
549               packet:          git< pathname=path/otherfile.dat
550               packet:          git< 0000
551               packet:          git< status=success
552               packet:          git< 0000
553
554           After Git received the pathnames, it will request the corresponding
555           blobs again. These requests contain a pathname and an empty content
556           section. The filter is expected to respond with the smudged content
557           in the usual way as explained above.
558
559               packet:          git> command=smudge
560               packet:          git> pathname=path/testfile.dat
561               packet:          git> 0000
562               packet:          git> 0000  # empty content!
563               packet:          git< status=success
564               packet:          git< 0000
565               packet:          git< SMUDGED_CONTENT
566               packet:          git< 0000
567               packet:          git< 0000  # empty list, keep "status=success" unchanged!
568
569       Example
570           A long running filter demo implementation can be found in
571           contrib/long-running-filter/example.pl located in the Git core
572           repository. If you develop your own long running filter process
573           then the GIT_TRACE_PACKET environment variables can be very helpful
574           for debugging (see git(1)).
575
576           Please note that you cannot use an existing filter.<driver>.clean
577           or filter.<driver>.smudge command with filter.<driver>.process
578           because the former two use a different inter process communication
579           protocol than the latter one.
580
581       Interaction between checkin/checkout attributes
582           In the check-in codepath, the worktree file is first converted with
583           filter driver (if specified and corresponding driver defined), then
584           the result is processed with ident (if specified), and then finally
585           with text (again, if specified and applicable).
586
587           In the check-out codepath, the blob content is first converted with
588           text, and then ident and fed to filter.
589
590       Merging branches with differing checkin/checkout attributes
591           If you have added attributes to a file that cause the canonical
592           repository format for that file to change, such as adding a
593           clean/smudge filter or text/eol/ident attributes, merging anything
594           where the attribute is not in place would normally cause merge
595           conflicts.
596
597           To prevent these unnecessary merge conflicts, Git can be told to
598           run a virtual check-out and check-in of all three stages of a file
599           when resolving a three-way merge by setting the merge.renormalize
600           configuration variable. This prevents changes caused by check-in
601           conversion from causing spurious merge conflicts when a converted
602           file is merged with an unconverted file.
603
604           As long as a "smudge→clean" results in the same output as a "clean"
605           even on files that are already smudged, this strategy will
606           automatically resolve all filter-related conflicts. Filters that do
607           not act in this way may cause additional merge conflicts that must
608           be resolved manually.
609
610   Generating diff text
611       diff
612           The attribute diff affects how Git generates diffs for particular
613           files. It can tell Git whether to generate a textual patch for the
614           path or to treat the path as a binary file. It can also affect what
615           line is shown on the hunk header @@ -k,l +n,m @@ line, tell Git to
616           use an external command to generate the diff, or ask Git to convert
617           binary files to a text format before generating the diff.
618
619           Set
620               A path to which the diff attribute is set is treated as text,
621               even when they contain byte values that normally never appear
622               in text files, such as NUL.
623
624           Unset
625               A path to which the diff attribute is unset will generate
626               Binary files differ (or a binary patch, if binary patches are
627               enabled).
628
629           Unspecified
630               A path to which the diff attribute is unspecified first gets
631               its contents inspected, and if it looks like text and is
632               smaller than core.bigFileThreshold, it is treated as text.
633               Otherwise it would generate Binary files differ.
634
635           String
636               Diff is shown using the specified diff driver. Each driver may
637               specify one or more options, as described in the following
638               section. The options for the diff driver "foo" are defined by
639               the configuration variables in the "diff.foo" section of the
640               Git config file.
641
642       Defining an external diff driver
643           The definition of a diff driver is done in gitconfig, not
644           gitattributes file, so strictly speaking this manual page is a
645           wrong place to talk about it. However...
646
647           To define an external diff driver jcdiff, add a section to your
648           $GIT_DIR/config file (or $HOME/.gitconfig file) like this:
649
650               [diff "jcdiff"]
651                       command = j-c-diff
652
653           When Git needs to show you a diff for the path with diff attribute
654           set to jcdiff, it calls the command you specified with the above
655           configuration, i.e. j-c-diff, with 7 parameters, just like
656           GIT_EXTERNAL_DIFF program is called. See git(1) for details.
657
658       Defining a custom hunk-header
659           Each group of changes (called a "hunk") in the textual diff output
660           is prefixed with a line of the form:
661
662               @@ -k,l +n,m @@ TEXT
663
664           This is called a hunk header. The "TEXT" portion is by default a
665           line that begins with an alphabet, an underscore or a dollar sign;
666           this matches what GNU diff -p output uses. This default selection
667           however is not suited for some contents, and you can use a
668           customized pattern to make a selection.
669
670           First, in .gitattributes, you would assign the diff attribute for
671           paths.
672
673               *.tex   diff=tex
674
675           Then, you would define a "diff.tex.xfuncname" configuration to
676           specify a regular expression that matches a line that you would
677           want to appear as the hunk header "TEXT". Add a section to your
678           $GIT_DIR/config file (or $HOME/.gitconfig file) like this:
679
680               [diff "tex"]
681                       xfuncname = "^(\\\\(sub)*section\\{.*)$"
682
683           Note. A single level of backslashes are eaten by the configuration
684           file parser, so you would need to double the backslashes; the
685           pattern above picks a line that begins with a backslash, and zero
686           or more occurrences of sub followed by section followed by open
687           brace, to the end of line.
688
689           There are a few built-in patterns to make this easier, and tex is
690           one of them, so you do not have to write the above in your
691           configuration file (you still need to enable this with the
692           attribute mechanism, via .gitattributes). The following built in
693           patterns are available:
694
695ada suitable for source code in the Ada language.
696
697bash suitable for source code in the Bourne-Again SHell
698               language. Covers a superset of POSIX shell function
699               definitions.
700
701bibtex suitable for files with BibTeX coded references.
702
703cpp suitable for source code in the C and C++ languages.
704
705csharp suitable for source code in the C# language.
706
707css suitable for cascading style sheets.
708
709dts suitable for devicetree (DTS) files.
710
711elixir suitable for source code in the Elixir language.
712
713fortran suitable for source code in the Fortran language.
714
715fountain suitable for Fountain documents.
716
717golang suitable for source code in the Go language.
718
719html suitable for HTML/XHTML documents.
720
721java suitable for source code in the Java language.
722
723markdown suitable for Markdown documents.
724
725matlab suitable for source code in the MATLAB and Octave
726               languages.
727
728objc suitable for source code in the Objective-C language.
729
730pascal suitable for source code in the Pascal/Delphi language.
731
732perl suitable for source code in the Perl language.
733
734php suitable for source code in the PHP language.
735
736python suitable for source code in the Python language.
737
738ruby suitable for source code in the Ruby language.
739
740rust suitable for source code in the Rust language.
741
742scheme suitable for source code in the Scheme language.
743
744tex suitable for source code for LaTeX documents.
745
746       Customizing word diff
747           You can customize the rules that git diff --word-diff uses to split
748           words in a line, by specifying an appropriate regular expression in
749           the "diff.*.wordRegex" configuration variable. For example, in TeX
750           a backslash followed by a sequence of letters forms a command, but
751           several such commands can be run together without intervening
752           whitespace. To separate them, use a regular expression in your
753           $GIT_DIR/config file (or $HOME/.gitconfig file) like this:
754
755               [diff "tex"]
756                       wordRegex = "\\\\[a-zA-Z]+|[{}]|\\\\.|[^\\{}[:space:]]+"
757
758           A built-in pattern is provided for all languages listed in the
759           previous section.
760
761       Performing text diffs of binary files
762           Sometimes it is desirable to see the diff of a text-converted
763           version of some binary files. For example, a word processor
764           document can be converted to an ASCII text representation, and the
765           diff of the text shown. Even though this conversion loses some
766           information, the resulting diff is useful for human viewing (but
767           cannot be applied directly).
768
769           The textconv config option is used to define a program for
770           performing such a conversion. The program should take a single
771           argument, the name of a file to convert, and produce the resulting
772           text on stdout.
773
774           For example, to show the diff of the exif information of a file
775           instead of the binary information (assuming you have the exif tool
776           installed), add the following section to your $GIT_DIR/config file
777           (or $HOME/.gitconfig file):
778
779               [diff "jpg"]
780                       textconv = exif
781
782
783               Note
784               The text conversion is generally a one-way conversion; in this
785               example, we lose the actual image contents and focus just on
786               the text data. This means that diffs generated by textconv are
787               not suitable for applying. For this reason, only git diff and
788               the git log family of commands (i.e., log, whatchanged, show)
789               will perform text conversion. git format-patch will never
790               generate this output. If you want to send somebody a
791               text-converted diff of a binary file (e.g., because it quickly
792               conveys the changes you have made), you should generate it
793               separately and send it as a comment in addition to the usual
794               binary diff that you might send.
795
796           Because text conversion can be slow, especially when doing a large
797           number of them with git log -p, Git provides a mechanism to cache
798           the output and use it in future diffs. To enable caching, set the
799           "cachetextconv" variable in your diff driver’s config. For example:
800
801               [diff "jpg"]
802                       textconv = exif
803                       cachetextconv = true
804
805           This will cache the result of running "exif" on each blob
806           indefinitely. If you change the textconv config variable for a diff
807           driver, Git will automatically invalidate the cache entries and
808           re-run the textconv filter. If you want to invalidate the cache
809           manually (e.g., because your version of "exif" was updated and now
810           produces better output), you can remove the cache manually with git
811           update-ref -d refs/notes/textconv/jpg (where "jpg" is the name of
812           the diff driver, as in the example above).
813
814       Choosing textconv versus external diff
815           If you want to show differences between binary or
816           specially-formatted blobs in your repository, you can choose to use
817           either an external diff command, or to use textconv to convert them
818           to a diff-able text format. Which method you choose depends on your
819           exact situation.
820
821           The advantage of using an external diff command is flexibility. You
822           are not bound to find line-oriented changes, nor is it necessary
823           for the output to resemble unified diff. You are free to locate and
824           report changes in the most appropriate way for your data format.
825
826           A textconv, by comparison, is much more limiting. You provide a
827           transformation of the data into a line-oriented text format, and
828           Git uses its regular diff tools to generate the output. There are
829           several advantages to choosing this method:
830
831            1. Ease of use. It is often much simpler to write a binary to text
832               transformation than it is to perform your own diff. In many
833               cases, existing programs can be used as textconv filters (e.g.,
834               exif, odt2txt).
835
836            2. Git diff features. By performing only the transformation step
837               yourself, you can still utilize many of Git’s diff features,
838               including colorization, word-diff, and combined diffs for
839               merges.
840
841            3. Caching. Textconv caching can speed up repeated diffs, such as
842               those you might trigger by running git log -p.
843
844       Marking files as binary
845           Git usually guesses correctly whether a blob contains text or
846           binary data by examining the beginning of the contents. However,
847           sometimes you may want to override its decision, either because a
848           blob contains binary data later in the file, or because the
849           content, while technically composed of text characters, is opaque
850           to a human reader. For example, many postscript files contain only
851           ASCII characters, but produce noisy and meaningless diffs.
852
853           The simplest way to mark a file as binary is to unset the diff
854           attribute in the .gitattributes file:
855
856               *.ps -diff
857
858           This will cause Git to generate Binary files differ (or a binary
859           patch, if binary patches are enabled) instead of a regular diff.
860
861           However, one may also want to specify other diff driver attributes.
862           For example, you might want to use textconv to convert postscript
863           files to an ASCII representation for human viewing, but otherwise
864           treat them as binary files. You cannot specify both -diff and
865           diff=ps attributes. The solution is to use the diff.*.binary config
866           option:
867
868               [diff "ps"]
869                 textconv = ps2ascii
870                 binary = true
871
872   Performing a three-way merge
873       merge
874           The attribute merge affects how three versions of a file are merged
875           when a file-level merge is necessary during git merge, and other
876           commands such as git revert and git cherry-pick.
877
878           Set
879               Built-in 3-way merge driver is used to merge the contents in a
880               way similar to merge command of RCS suite. This is suitable for
881               ordinary text files.
882
883           Unset
884               Take the version from the current branch as the tentative merge
885               result, and declare that the merge has conflicts. This is
886               suitable for binary files that do not have a well-defined merge
887               semantics.
888
889           Unspecified
890               By default, this uses the same built-in 3-way merge driver as
891               is the case when the merge attribute is set. However, the
892               merge.default configuration variable can name different merge
893               driver to be used with paths for which the merge attribute is
894               unspecified.
895
896           String
897               3-way merge is performed using the specified custom merge
898               driver. The built-in 3-way merge driver can be explicitly
899               specified by asking for "text" driver; the built-in "take the
900               current branch" driver can be requested with "binary".
901
902       Built-in merge drivers
903           There are a few built-in low-level merge drivers defined that can
904           be asked for via the merge attribute.
905
906           text
907               Usual 3-way file level merge for text files. Conflicted regions
908               are marked with conflict markers <<<<<<<, ======= and >>>>>>>.
909               The version from your branch appears before the ======= marker,
910               and the version from the merged branch appears after the
911               ======= marker.
912
913           binary
914               Keep the version from your branch in the work tree, but leave
915               the path in the conflicted state for the user to sort out.
916
917           union
918               Run 3-way file level merge for text files, but take lines from
919               both versions, instead of leaving conflict markers. This tends
920               to leave the added lines in the resulting file in random order
921               and the user should verify the result. Do not use this if you
922               do not understand the implications.
923
924       Defining a custom merge driver
925           The definition of a merge driver is done in the .git/config file,
926           not in the gitattributes file, so strictly speaking this manual
927           page is a wrong place to talk about it. However...
928
929           To define a custom merge driver filfre, add a section to your
930           $GIT_DIR/config file (or $HOME/.gitconfig file) like this:
931
932               [merge "filfre"]
933                       name = feel-free merge driver
934                       driver = filfre %O %A %B %L %P
935                       recursive = binary
936
937           The merge.*.name variable gives the driver a human-readable name.
938
939           The merge.*.driver variable’s value is used to construct a command
940           to run to merge ancestor’s version (%O), current version (%A) and
941           the other branches' version (%B). These three tokens are replaced
942           with the names of temporary files that hold the contents of these
943           versions when the command line is built. Additionally, %L will be
944           replaced with the conflict marker size (see below).
945
946           The merge driver is expected to leave the result of the merge in
947           the file named with %A by overwriting it, and exit with zero status
948           if it managed to merge them cleanly, or non-zero if there were
949           conflicts.
950
951           The merge.*.recursive variable specifies what other merge driver to
952           use when the merge driver is called for an internal merge between
953           common ancestors, when there are more than one. When left
954           unspecified, the driver itself is used for both internal merge and
955           the final merge.
956
957           The merge driver can learn the pathname in which the merged result
958           will be stored via placeholder %P.
959
960       conflict-marker-size
961           This attribute controls the length of conflict markers left in the
962           work tree file during a conflicted merge. Only setting to the value
963           to a positive integer has any meaningful effect.
964
965           For example, this line in .gitattributes can be used to tell the
966           merge machinery to leave much longer (instead of the usual
967           7-character-long) conflict markers when merging the file
968           Documentation/git-merge.txt results in a conflict.
969
970               Documentation/git-merge.txt     conflict-marker-size=32
971
972   Checking whitespace errors
973       whitespace
974           The core.whitespace configuration variable allows you to define
975           what diff and apply should consider whitespace errors for all paths
976           in the project (See git-config(1)). This attribute gives you finer
977           control per path.
978
979           Set
980               Notice all types of potential whitespace errors known to Git.
981               The tab width is taken from the value of the core.whitespace
982               configuration variable.
983
984           Unset
985               Do not notice anything as error.
986
987           Unspecified
988               Use the value of the core.whitespace configuration variable to
989               decide what to notice as error.
990
991           String
992               Specify a comma separate list of common whitespace problems to
993               notice in the same format as the core.whitespace configuration
994               variable.
995
996   Creating an archive
997       export-ignore
998           Files and directories with the attribute export-ignore won’t be
999           added to archive files.
1000
1001       export-subst
1002           If the attribute export-subst is set for a file then Git will
1003           expand several placeholders when adding this file to an archive.
1004           The expansion depends on the availability of a commit ID, i.e., if
1005           git-archive(1) has been given a tree instead of a commit or a tag
1006           then no replacement will be done. The placeholders are the same as
1007           those for the option --pretty=format: of git-log(1), except that
1008           they need to be wrapped like this: $Format:PLACEHOLDERS$ in the
1009           file. E.g. the string $Format:%H$ will be replaced by the commit
1010           hash. However, only one %(describe) placeholder is expanded per
1011           archive to avoid denial-of-service attacks.
1012
1013   Packing objects
1014       delta
1015           Delta compression will not be attempted for blobs for paths with
1016           the attribute delta set to false.
1017
1018   Viewing files in GUI tools
1019       encoding
1020           The value of this attribute specifies the character encoding that
1021           should be used by GUI tools (e.g. gitk(1) and git-gui(1)) to
1022           display the contents of the relevant file. Note that due to
1023           performance considerations gitk(1) does not use this attribute
1024           unless you manually enable per-file encodings in its options.
1025
1026           If this attribute is not set or has an invalid value, the value of
1027           the gui.encoding configuration variable is used instead (See git-
1028           config(1)).
1029

USING MACRO ATTRIBUTES

1031       You do not want any end-of-line conversions applied to, nor textual
1032       diffs produced for, any binary file you track. You would need to
1033       specify e.g.
1034
1035           *.jpg -text -diff
1036
1037       but that may become cumbersome, when you have many attributes. Using
1038       macro attributes, you can define an attribute that, when set, also sets
1039       or unsets a number of other attributes at the same time. The system
1040       knows a built-in macro attribute, binary:
1041
1042           *.jpg binary
1043
1044       Setting the "binary" attribute also unsets the "text" and "diff"
1045       attributes as above. Note that macro attributes can only be "Set",
1046       though setting one might have the effect of setting or unsetting other
1047       attributes or even returning other attributes to the "Unspecified"
1048       state.
1049

DEFINING MACRO ATTRIBUTES

1051       Custom macro attributes can be defined only in top-level gitattributes
1052       files ($GIT_DIR/info/attributes, the .gitattributes file at the top
1053       level of the working tree, or the global or system-wide gitattributes
1054       files), not in .gitattributes files in working tree subdirectories. The
1055       built-in macro attribute "binary" is equivalent to:
1056
1057           [attr]binary -diff -merge -text
1058

NOTES

1060       Git does not follow symbolic links when accessing a .gitattributes file
1061       in the working tree. This keeps behavior consistent when the file is
1062       accessed from the index or a tree versus from the filesystem.
1063

EXAMPLES

1065       If you have these three gitattributes file:
1066
1067           (in $GIT_DIR/info/attributes)
1068
1069           a*      foo !bar -baz
1070
1071           (in .gitattributes)
1072           abc     foo bar baz
1073
1074           (in t/.gitattributes)
1075           ab*     merge=filfre
1076           abc     -foo -bar
1077           *.c     frotz
1078
1079       the attributes given to path t/abc are computed as follows:
1080
1081        1. By examining t/.gitattributes (which is in the same directory as
1082           the path in question), Git finds that the first line matches.
1083           merge attribute is set. It also finds that the second line matches,
1084           and attributes foo and bar are unset.
1085
1086        2. Then it examines .gitattributes (which is in the parent directory),
1087           and finds that the first line matches, but t/.gitattributes file
1088           already decided how merge, foo and bar attributes should be given
1089           to this path, so it leaves foo and bar unset. Attribute baz is set.
1090
1091        3. Finally it examines $GIT_DIR/info/attributes. This file is used to
1092           override the in-tree settings. The first line is a match, and foo
1093           is set, bar is reverted to unspecified state, and baz is unset.
1094
1095       As the result, the attributes assignment to t/abc becomes:
1096
1097           foo     set to true
1098           bar     unspecified
1099           baz     set to false
1100           merge   set to string value "filfre"
1101           frotz   unspecified
1102

SEE ALSO

1104       git-check-attr(1).
1105

GIT

1107       Part of the git(1) suite
1108
1109
1110
1111Git 2.33.1                        2021-10-12                  GITATTRIBUTES(5)
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