Documentation / gitattributes.txton commit diff: add synonyms for -M, -C, -B (37ab515)
   1gitattributes(5)
   2================
   3
   4NAME
   5----
   6gitattributes - defining attributes per path
   7
   8SYNOPSIS
   9--------
  10$GIT_DIR/info/attributes, .gitattributes
  11
  12
  13DESCRIPTION
  14-----------
  15
  16A `gitattributes` file is a simple text file that gives
  17`attributes` to pathnames.
  18
  19Each line in `gitattributes` file is of form:
  20
  21        pattern attr1 attr2 ...
  22
  23That is, a pattern followed by an attributes list,
  24separated by whitespaces.  When the pattern matches the
  25path in question, the attributes listed on the line are given to
  26the path.
  27
  28Each attribute can be in one of these states for a given path:
  29
  30Set::
  31
  32        The path has the attribute with special value "true";
  33        this is specified by listing only the name of the
  34        attribute in the attribute list.
  35
  36Unset::
  37
  38        The path has the attribute with special value "false";
  39        this is specified by listing the name of the attribute
  40        prefixed with a dash `-` in the attribute list.
  41
  42Set to a value::
  43
  44        The path has the attribute with specified string value;
  45        this is specified by listing the name of the attribute
  46        followed by an equal sign `=` and its value in the
  47        attribute list.
  48
  49Unspecified::
  50
  51        No pattern matches the path, and nothing says if
  52        the path has or does not have the attribute, the
  53        attribute for the path is said to be Unspecified.
  54
  55When more than one pattern matches the path, a later line
  56overrides an earlier line.  This overriding is done per
  57attribute.  The rules how the pattern matches paths are the
  58same as in `.gitignore` files; see linkgit:gitignore[5].
  59
  60When deciding what attributes are assigned to a path, git
  61consults `$GIT_DIR/info/attributes` file (which has the highest
  62precedence), `.gitattributes` file in the same directory as the
  63path in question, and its parent directories up to the toplevel of the
  64work tree (the further the directory that contains `.gitattributes`
  65is from the path in question, the lower its precedence).
  66
  67If you wish to affect only a single repository (i.e., to assign
  68attributes to files that are particular to one user's workflow), then
  69attributes should be placed in the `$GIT_DIR/info/attributes` file.
  70Attributes which should be version-controlled and distributed to other
  71repositories (i.e., attributes of interest to all users) should go into
  72`.gitattributes` files.
  73
  74Sometimes you would need to override an setting of an attribute
  75for a path to `unspecified` state.  This can be done by listing
  76the name of the attribute prefixed with an exclamation point `!`.
  77
  78
  79EFFECTS
  80-------
  81
  82Certain operations by git can be influenced by assigning
  83particular attributes to a path.  Currently, the following
  84operations are attributes-aware.
  85
  86Checking-out and checking-in
  87~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  88
  89These attributes affect how the contents stored in the
  90repository are copied to the working tree files when commands
  91such as 'git checkout' and 'git merge' run.  They also affect how
  92git stores the contents you prepare in the working tree in the
  93repository upon 'git add' and 'git commit'.
  94
  95`text`
  96^^^^^^
  97
  98This attribute enables and controls end-of-line normalization.  When a
  99text file is normalized, its line endings are converted to LF in the
 100repository.  To control what line ending style is used in the working
 101directory, use the `eol` attribute for a single file and the
 102`core.eol` configuration variable for all text files.
 103
 104Set::
 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
 110Unset::
 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
 115Set 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
 121Unspecified::
 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
 127Any other value causes git to act as if `text` has been left
 128unspecified.
 129
 130`eol`
 131^^^^^
 132
 133This attribute sets a specific line-ending style to be used in the
 134working directory.  It enables end-of-line normalization without any
 135content checks, effectively setting the `text` attribute.
 136
 137Set 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
 143Set 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
 149Backwards compatibility with `crlf` attribute
 150^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 151
 152For backwards compatibility, the `crlf` attribute is interpreted as
 153follows:
 154
 155------------------------
 156crlf            text
 157-crlf           -text
 158crlf=input      eol=lf
 159------------------------
 160
 161End-of-line conversion
 162^^^^^^^^^^^^^^^^^^^^^^
 163
 164While git normally leaves file contents alone, it can be configured to
 165normalize line endings to LF in the repository and, optionally, to
 166convert them to CRLF when files are checked out.
 167
 168Here is an example that will make git normalize .txt, .vcproj and .sh
 169files, ensure that .vcproj files have CRLF and .sh files have LF in
 170the working directory, and prevent .jpg files from being normalized
 171regardless of their content.
 172
 173------------------------
 174*.txt           text
 175*.vcproj        eol=crlf
 176*.sh            eol=lf
 177*.jpg           -text
 178------------------------
 179
 180Other source code management systems normalize all text files in their
 181repositories, and there are two ways to enable similar automatic
 182normalization in git.
 183
 184If you simply want to have CRLF line endings in your working directory
 185regardless of the repository you are working with, you can set the
 186config variable "core.autocrlf" without changing any attributes.
 187
 188------------------------
 189[core]
 190        autocrlf = true
 191------------------------
 192
 193This does not force normalization of all text files, but does ensure
 194that text files that you introduce to the repository have their line
 195endings normalized to LF when they are added, and that files that are
 196already normalized in the repository stay normalized.
 197
 198If you want to interoperate with a source code management system that
 199enforces end-of-line normalization, or you simply want all text files
 200in your repository to be normalized, you should instead set the `text`
 201attribute to "auto" for _all_ files.
 202
 203------------------------
 204*       text=auto
 205------------------------
 206
 207This ensures that all files that git considers to be text will have
 208normalized (LF) line endings in the repository.  The `core.eol`
 209configuration variable controls which line endings git will use for
 210normalized files in your working directory; the default is to use the
 211native line ending for your platform, or CRLF if `core.autocrlf` is
 212set.
 213
 214NOTE: When `text=auto` normalization is enabled in an existing
 215repository, any text files containing CRLFs should be normalized.  If
 216they are not they will be normalized the next time someone tries to
 217change them, causing unfortunate misattribution.  From a clean working
 218directory:
 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
 230If any files that should not be normalized show up in 'git status',
 231unset their `text` attribute before running 'git add -u'.
 232
 233------------------------
 234manual.pdf      -text
 235------------------------
 236
 237Conversely, text files that git does not detect can have normalization
 238enabled manually.
 239
 240------------------------
 241weirdchars.txt  text
 242------------------------
 243
 244If `core.safecrlf` is set to "true" or "warn", git verifies if
 245the conversion is reversible for the current setting of
 246`core.autocrlf`.  For "true", git rejects irreversible
 247conversions; for "warn", git only prints a warning but accepts
 248an irreversible conversion.  The safety triggers to prevent such
 249a conversion done to the files in the work tree, but there are a
 250few 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
 268When the attribute `ident` is set for a path, git replaces
 269`$Id$` in the blob object with `$Id:`, followed by the
 27040-character hexadecimal blob object name, followed by a dollar
 271sign `$` upon checkout.  Any byte sequence that begins with
 272`$Id:` and ends with `$` in the worktree file is replaced
 273with `$Id$` upon check-in.
 274
 275
 276`filter`
 277^^^^^^^^
 278
 279A `filter` attribute can be set to a string value that names a
 280filter driver specified in the configuration.
 281
 282A filter driver consists of a `clean` command and a `smudge`
 283command, either of which can be left unspecified.  Upon
 284checkout, when the `smudge` command is specified, the command is
 285fed the blob object from its standard input, and its standard
 286output is used to update the worktree file.  Similarly, the
 287`clean` command is used to convert the contents of worktree file
 288upon checkin.
 289
 290A missing filter driver definition in the config is not an error
 291but makes the filter a no-op passthru.
 292
 293The content filtering is done to massage the content into a
 294shape that is more convenient for the platform, filesystem, and
 295the user to use.  The key phrase here is "more convenient" and not
 296"turning something unusable into usable".  In other words, the
 297intent is that if someone unsets the filter driver definition,
 298or does not have the appropriate filter program, the project
 299should still be usable.
 300
 301For example, in .gitattributes, you would assign the `filter`
 302attribute for paths.
 303
 304------------------------
 305*.c     filter=indent
 306------------------------
 307
 308Then you would define a "filter.indent.clean" and "filter.indent.smudge"
 309configuration in your .git/config to specify a pair of commands to
 310modify the contents of C programs when the source files are checked
 311in ("clean" is run) and checked out (no change is made because the
 312command is "cat").
 313
 314------------------------
 315[filter "indent"]
 316        clean = indent
 317        smudge = cat
 318------------------------
 319
 320For best results, `clean` should not alter its output further if it is
 321run twice ("clean->clean" should be equivalent to "clean"), and
 322multiple `smudge` commands should not alter `clean`'s output
 323("smudge->smudge->clean" should be equivalent to "clean").  See the
 324section on merging below.
 325
 326The "indent" filter is well-behaved in this regard: it will not modify
 327input that is already correctly indented.  In this case, the lack of a
 328smudge filter means that the clean filter _must_ accept its own output
 329without modifying it.
 330
 331
 332Interaction between checkin/checkout attributes
 333^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 334
 335In the check-in codepath, the worktree file is first converted
 336with `filter` driver (if specified and corresponding driver
 337defined), then the result is processed with `ident` (if
 338specified), and then finally with `text` (again, if specified
 339and applicable).
 340
 341In the check-out codepath, the blob content is first converted
 342with `text`, and then `ident` and fed to `filter`.
 343
 344
 345Merging branches with differing checkin/checkout attributes
 346^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 347
 348If you have added attributes to a file that cause the canonical
 349repository format for that file to change, such as adding a
 350clean/smudge filter or text/eol/ident attributes, merging anything
 351where the attribute is not in place would normally cause merge
 352conflicts.
 353
 354To prevent these unnecessary merge conflicts, git can be told to run a
 355virtual check-out and check-in of all three stages of a file when
 356resolving a three-way merge by setting the `merge.renormalize`
 357configuration variable.  This prevents changes caused by check-in
 358conversion from causing spurious merge conflicts when a converted file
 359is merged with an unconverted file.
 360
 361As long as a "smudge->clean" results in the same output as a "clean"
 362even on files that are already smudged, this strategy will
 363automatically resolve all filter-related conflicts.  Filters that do
 364not act in this way may cause additional merge conflicts that must be
 365resolved manually.
 366
 367
 368Generating diff text
 369~~~~~~~~~~~~~~~~~~~~
 370
 371`diff`
 372^^^^^^
 373
 374The attribute `diff` affects how 'git' generates diffs for particular
 375files. It can tell git whether to generate a textual patch for the path
 376or to treat the path as a binary file.  It can also affect what line is
 377shown on the hunk header `@@ -k,l +n,m @@` line, tell git to use an
 378external command to generate the diff, or ask git to convert binary
 379files to a text format before generating the diff.
 380
 381Set::
 382
 383        A path to which the `diff` attribute is set is treated
 384        as text, even when they contain byte values that
 385        normally never appear in text files, such as NUL.
 386
 387Unset::
 388
 389        A path to which the `diff` attribute is unset will
 390        generate `Binary files differ` (or a binary patch, if
 391        binary patches are enabled).
 392
 393Unspecified::
 394
 395        A path to which the `diff` attribute is unspecified
 396        first gets its contents inspected, and if it looks like
 397        text, it is treated as text.  Otherwise it would
 398        generate `Binary files differ`.
 399
 400String::
 401
 402        Diff is shown using the specified diff driver.  Each driver may
 403        specify one or more options, as described in the following
 404        section. The options for the diff driver "foo" are defined
 405        by the configuration variables in the "diff.foo" section of the
 406        git config file.
 407
 408
 409Defining an external diff driver
 410^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 411
 412The definition of a diff driver is done in `gitconfig`, not
 413`gitattributes` file, so strictly speaking this manual page is a
 414wrong place to talk about it.  However...
 415
 416To define an external diff driver `jcdiff`, add a section to your
 417`$GIT_DIR/config` file (or `$HOME/.gitconfig` file) like this:
 418
 419----------------------------------------------------------------
 420[diff "jcdiff"]
 421        command = j-c-diff
 422----------------------------------------------------------------
 423
 424When git needs to show you a diff for the path with `diff`
 425attribute set to `jcdiff`, it calls the command you specified
 426with the above configuration, i.e. `j-c-diff`, with 7
 427parameters, just like `GIT_EXTERNAL_DIFF` program is called.
 428See linkgit:git[1] for details.
 429
 430
 431Defining a custom hunk-header
 432^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 433
 434Each group of changes (called a "hunk") in the textual diff output
 435is prefixed with a line of the form:
 436
 437        @@ -k,l +n,m @@ TEXT
 438
 439This is called a 'hunk header'.  The "TEXT" portion is by default a line
 440that begins with an alphabet, an underscore or a dollar sign; this
 441matches what GNU 'diff -p' output uses.  This default selection however
 442is not suited for some contents, and you can use a customized pattern
 443to make a selection.
 444
 445First, in .gitattributes, you would assign the `diff` attribute
 446for paths.
 447
 448------------------------
 449*.tex   diff=tex
 450------------------------
 451
 452Then, you would define a "diff.tex.xfuncname" configuration to
 453specify a regular expression that matches a line that you would
 454want to appear as the hunk header "TEXT". Add a section to your
 455`$GIT_DIR/config` file (or `$HOME/.gitconfig` file) like this:
 456
 457------------------------
 458[diff "tex"]
 459        xfuncname = "^(\\\\(sub)*section\\{.*)$"
 460------------------------
 461
 462Note.  A single level of backslashes are eaten by the
 463configuration file parser, so you would need to double the
 464backslashes; the pattern above picks a line that begins with a
 465backslash, and zero or more occurrences of `sub` followed by
 466`section` followed by open brace, to the end of line.
 467
 468There are a few built-in patterns to make this easier, and `tex`
 469is one of them, so you do not have to write the above in your
 470configuration file (you still need to enable this with the
 471attribute mechanism, via `.gitattributes`).  The following built in
 472patterns are available:
 473
 474- `bibtex` suitable for files with BibTeX coded references.
 475
 476- `cpp` suitable for source code in the C and C++ languages.
 477
 478- `html` suitable for HTML/XHTML documents.
 479
 480- `java` suitable for source code in the Java language.
 481
 482- `objc` suitable for source code in the Objective-C language.
 483
 484- `pascal` suitable for source code in the Pascal/Delphi language.
 485
 486- `php` suitable for source code in the PHP language.
 487
 488- `python` suitable for source code in the Python language.
 489
 490- `ruby` suitable for source code in the Ruby language.
 491
 492- `tex` suitable for source code for LaTeX documents.
 493
 494
 495Customizing word diff
 496^^^^^^^^^^^^^^^^^^^^^
 497
 498You can customize the rules that `git diff --word-diff` uses to
 499split words in a line, by specifying an appropriate regular expression
 500in the "diff.*.wordRegex" configuration variable.  For example, in TeX
 501a backslash followed by a sequence of letters forms a command, but
 502several such commands can be run together without intervening
 503whitespace.  To separate them, use a regular expression in your
 504`$GIT_DIR/config` file (or `$HOME/.gitconfig` file) like this:
 505
 506------------------------
 507[diff "tex"]
 508        wordRegex = "\\\\[a-zA-Z]+|[{}]|\\\\.|[^\\{}[:space:]]+"
 509------------------------
 510
 511A built-in pattern is provided for all languages listed in the
 512previous section.
 513
 514
 515Performing text diffs of binary files
 516^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 517
 518Sometimes it is desirable to see the diff of a text-converted
 519version of some binary files. For example, a word processor
 520document can be converted to an ASCII text representation, and
 521the diff of the text shown. Even though this conversion loses
 522some information, the resulting diff is useful for human
 523viewing (but cannot be applied directly).
 524
 525The `textconv` config option is used to define a program for
 526performing such a conversion. The program should take a single
 527argument, the name of a file to convert, and produce the
 528resulting text on stdout.
 529
 530For example, to show the diff of the exif information of a
 531file instead of the binary information (assuming you have the
 532exif tool installed), add the following section to your
 533`$GIT_DIR/config` file (or `$HOME/.gitconfig` file):
 534
 535------------------------
 536[diff "jpg"]
 537        textconv = exif
 538------------------------
 539
 540NOTE: The text conversion is generally a one-way conversion;
 541in this example, we lose the actual image contents and focus
 542just on the text data. This means that diffs generated by
 543textconv are _not_ suitable for applying. For this reason,
 544only `git diff` and the `git log` family of commands (i.e.,
 545log, whatchanged, show) will perform text conversion. `git
 546format-patch` will never generate this output. If you want to
 547send somebody a text-converted diff of a binary file (e.g.,
 548because it quickly conveys the changes you have made), you
 549should generate it separately and send it as a comment _in
 550addition to_ the usual binary diff that you might send.
 551
 552Because text conversion can be slow, especially when doing a
 553large number of them with `git log -p`, git provides a mechanism
 554to cache the output and use it in future diffs.  To enable
 555caching, set the "cachetextconv" variable in your diff driver's
 556config. For example:
 557
 558------------------------
 559[diff "jpg"]
 560        textconv = exif
 561        cachetextconv = true
 562------------------------
 563
 564This will cache the result of running "exif" on each blob
 565indefinitely. If you change the textconv config variable for a
 566diff driver, git will automatically invalidate the cache entries
 567and re-run the textconv filter. If you want to invalidate the
 568cache manually (e.g., because your version of "exif" was updated
 569and now produces better output), you can remove the cache
 570manually with `git update-ref -d refs/notes/textconv/jpg` (where
 571"jpg" is the name of the diff driver, as in the example above).
 572
 573Performing a three-way merge
 574~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 575
 576`merge`
 577^^^^^^^
 578
 579The attribute `merge` affects how three versions of a file is
 580merged when a file-level merge is necessary during `git merge`,
 581and other commands such as `git revert` and `git cherry-pick`.
 582
 583Set::
 584
 585        Built-in 3-way merge driver is used to merge the
 586        contents in a way similar to 'merge' command of `RCS`
 587        suite.  This is suitable for ordinary text files.
 588
 589Unset::
 590
 591        Take the version from the current branch as the
 592        tentative merge result, and declare that the merge has
 593        conflicts.  This is suitable for binary files that does
 594        not have a well-defined merge semantics.
 595
 596Unspecified::
 597
 598        By default, this uses the same built-in 3-way merge
 599        driver as is the case the `merge` attribute is set.
 600        However, `merge.default` configuration variable can name
 601        different merge driver to be used for paths to which the
 602        `merge` attribute is unspecified.
 603
 604String::
 605
 606        3-way merge is performed using the specified custom
 607        merge driver.  The built-in 3-way merge driver can be
 608        explicitly specified by asking for "text" driver; the
 609        built-in "take the current branch" driver can be
 610        requested with "binary".
 611
 612
 613Built-in merge drivers
 614^^^^^^^^^^^^^^^^^^^^^^
 615
 616There are a few built-in low-level merge drivers defined that
 617can be asked for via the `merge` attribute.
 618
 619text::
 620
 621        Usual 3-way file level merge for text files.  Conflicted
 622        regions are marked with conflict markers `<<<<<<<`,
 623        `=======` and `>>>>>>>`.  The version from your branch
 624        appears before the `=======` marker, and the version
 625        from the merged branch appears after the `=======`
 626        marker.
 627
 628binary::
 629
 630        Keep the version from your branch in the work tree, but
 631        leave the path in the conflicted state for the user to
 632        sort out.
 633
 634union::
 635
 636        Run 3-way file level merge for text files, but take
 637        lines from both versions, instead of leaving conflict
 638        markers.  This tends to leave the added lines in the
 639        resulting file in random order and the user should
 640        verify the result. Do not use this if you do not
 641        understand the implications.
 642
 643
 644Defining a custom merge driver
 645^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 646
 647The definition of a merge driver is done in the `.git/config`
 648file, not in the `gitattributes` file, so strictly speaking this
 649manual page is a wrong place to talk about it.  However...
 650
 651To define a custom merge driver `filfre`, add a section to your
 652`$GIT_DIR/config` file (or `$HOME/.gitconfig` file) like this:
 653
 654----------------------------------------------------------------
 655[merge "filfre"]
 656        name = feel-free merge driver
 657        driver = filfre %O %A %B
 658        recursive = binary
 659----------------------------------------------------------------
 660
 661The `merge.*.name` variable gives the driver a human-readable
 662name.
 663
 664The `merge.*.driver` variable's value is used to construct a
 665command to run to merge ancestor's version (`%O`), current
 666version (`%A`) and the other branches' version (`%B`).  These
 667three tokens are replaced with the names of temporary files that
 668hold the contents of these versions when the command line is
 669built. Additionally, %L will be replaced with the conflict marker
 670size (see below).
 671
 672The merge driver is expected to leave the result of the merge in
 673the file named with `%A` by overwriting it, and exit with zero
 674status if it managed to merge them cleanly, or non-zero if there
 675were conflicts.
 676
 677The `merge.*.recursive` variable specifies what other merge
 678driver to use when the merge driver is called for an internal
 679merge between common ancestors, when there are more than one.
 680When left unspecified, the driver itself is used for both
 681internal merge and the final merge.
 682
 683
 684`conflict-marker-size`
 685^^^^^^^^^^^^^^^^^^^^^^
 686
 687This attribute controls the length of conflict markers left in
 688the work tree file during a conflicted merge.  Only setting to
 689the value to a positive integer has any meaningful effect.
 690
 691For example, this line in `.gitattributes` can be used to tell the merge
 692machinery to leave much longer (instead of the usual 7-character-long)
 693conflict markers when merging the file `Documentation/git-merge.txt`
 694results in a conflict.
 695
 696------------------------
 697Documentation/git-merge.txt     conflict-marker-size=32
 698------------------------
 699
 700
 701Checking whitespace errors
 702~~~~~~~~~~~~~~~~~~~~~~~~~~
 703
 704`whitespace`
 705^^^^^^^^^^^^
 706
 707The `core.whitespace` configuration variable allows you to define what
 708'diff' and 'apply' should consider whitespace errors for all paths in
 709the project (See linkgit:git-config[1]).  This attribute gives you finer
 710control per path.
 711
 712Set::
 713
 714        Notice all types of potential whitespace errors known to git.
 715
 716Unset::
 717
 718        Do not notice anything as error.
 719
 720Unspecified::
 721
 722        Use the value of `core.whitespace` configuration variable to
 723        decide what to notice as error.
 724
 725String::
 726
 727        Specify a comma separate list of common whitespace problems to
 728        notice in the same format as `core.whitespace` configuration
 729        variable.
 730
 731
 732Creating an archive
 733~~~~~~~~~~~~~~~~~~~
 734
 735`export-ignore`
 736^^^^^^^^^^^^^^^
 737
 738Files and directories with the attribute `export-ignore` won't be added to
 739archive files.
 740
 741`export-subst`
 742^^^^^^^^^^^^^^
 743
 744If the attribute `export-subst` is set for a file then git will expand
 745several placeholders when adding this file to an archive.  The
 746expansion depends on the availability of a commit ID, i.e., if
 747linkgit:git-archive[1] has been given a tree instead of a commit or a
 748tag then no replacement will be done.  The placeholders are the same
 749as those for the option `--pretty=format:` of linkgit:git-log[1],
 750except that they need to be wrapped like this: `$Format:PLACEHOLDERS$`
 751in the file.  E.g. the string `$Format:%H$` will be replaced by the
 752commit hash.
 753
 754
 755Packing objects
 756~~~~~~~~~~~~~~~
 757
 758`delta`
 759^^^^^^^
 760
 761Delta compression will not be attempted for blobs for paths with the
 762attribute `delta` set to false.
 763
 764
 765Viewing files in GUI tools
 766~~~~~~~~~~~~~~~~~~~~~~~~~~
 767
 768`encoding`
 769^^^^^^^^^^
 770
 771The value of this attribute specifies the character encoding that should
 772be used by GUI tools (e.g. linkgit:gitk[1] and linkgit:git-gui[1]) to
 773display the contents of the relevant file. Note that due to performance
 774considerations linkgit:gitk[1] does not use this attribute unless you
 775manually enable per-file encodings in its options.
 776
 777If this attribute is not set or has an invalid value, the value of the
 778`gui.encoding` configuration variable is used instead
 779(See linkgit:git-config[1]).
 780
 781
 782USING ATTRIBUTE MACROS
 783----------------------
 784
 785You do not want any end-of-line conversions applied to, nor textual diffs
 786produced for, any binary file you track.  You would need to specify e.g.
 787
 788------------
 789*.jpg -text -diff
 790------------
 791
 792but that may become cumbersome, when you have many attributes.  Using
 793attribute macros, you can specify groups of attributes set or unset at
 794the same time.  The system knows a built-in attribute macro, `binary`:
 795
 796------------
 797*.jpg binary
 798------------
 799
 800which is equivalent to the above.  Note that the attribute macros can only
 801be "Set" (see the above example that sets "binary" macro as if it were an
 802ordinary attribute --- setting it in turn unsets "text" and "diff").
 803
 804
 805DEFINING ATTRIBUTE MACROS
 806-------------------------
 807
 808Custom attribute macros can be defined only in the `.gitattributes` file
 809at the toplevel (i.e. not in any subdirectory).  The built-in attribute
 810macro "binary" is equivalent to:
 811
 812------------
 813[attr]binary -diff -text
 814------------
 815
 816
 817EXAMPLE
 818-------
 819
 820If you have these three `gitattributes` file:
 821
 822----------------------------------------------------------------
 823(in $GIT_DIR/info/attributes)
 824
 825a*      foo !bar -baz
 826
 827(in .gitattributes)
 828abc     foo bar baz
 829
 830(in t/.gitattributes)
 831ab*     merge=filfre
 832abc     -foo -bar
 833*.c     frotz
 834----------------------------------------------------------------
 835
 836the attributes given to path `t/abc` are computed as follows:
 837
 8381. By examining `t/.gitattributes` (which is in the same
 839   directory as the path in question), git finds that the first
 840   line matches.  `merge` attribute is set.  It also finds that
 841   the second line matches, and attributes `foo` and `bar`
 842   are unset.
 843
 8442. Then it examines `.gitattributes` (which is in the parent
 845   directory), and finds that the first line matches, but
 846   `t/.gitattributes` file already decided how `merge`, `foo`
 847   and `bar` attributes should be given to this path, so it
 848   leaves `foo` and `bar` unset.  Attribute `baz` is set.
 849
 8503. Finally it examines `$GIT_DIR/info/attributes`.  This file
 851   is used to override the in-tree settings.  The first line is
 852   a match, and `foo` is set, `bar` is reverted to unspecified
 853   state, and `baz` is unset.
 854
 855As the result, the attributes assignment to `t/abc` becomes:
 856
 857----------------------------------------------------------------
 858foo     set to true
 859bar     unspecified
 860baz     set to false
 861merge   set to string value "filfre"
 862frotz   unspecified
 863----------------------------------------------------------------
 864
 865
 866
 867GIT
 868---
 869Part of the linkgit:git[1] suite