Documentation / gitattributes.txton commit user-manual: remote-tracking can be checked out, with detached HEAD (45dfd40)
   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). Finally
  66global and system-wide files are considered (they have the lowest
  67precedence).
  68
  69If you wish to affect only a single repository (i.e., to assign
  70attributes to files that are particular to
  71one user's workflow for that repository), then
  72attributes should be placed in the `$GIT_DIR/info/attributes` file.
  73Attributes which should be version-controlled and distributed to other
  74repositories (i.e., attributes of interest to all users) should go into
  75`.gitattributes` files. Attributes that should affect all repositories
  76for a single user should be placed in a file specified by the
  77`core.attributesfile` configuration option (see linkgit:git-config[1]).
  78Attributes for all users on a system should be placed in the
  79`$(prefix)/etc/gitattributes` file.
  80
  81Sometimes you would need to override an setting of an attribute
  82for a path to `unspecified` state.  This can be done by listing
  83the name of the attribute prefixed with an exclamation point `!`.
  84
  85
  86EFFECTS
  87-------
  88
  89Certain operations by git can be influenced by assigning
  90particular attributes to a path.  Currently, the following
  91operations are attributes-aware.
  92
  93Checking-out and checking-in
  94~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  95
  96These attributes affect how the contents stored in the
  97repository are copied to the working tree files when commands
  98such as 'git checkout' and 'git merge' run.  They also affect how
  99git stores the contents you prepare in the working tree in the
 100repository upon 'git add' and 'git commit'.
 101
 102`text`
 103^^^^^^
 104
 105This attribute enables and controls end-of-line normalization.  When a
 106text file is normalized, its line endings are converted to LF in the
 107repository.  To control what line ending style is used in the working
 108directory, use the `eol` attribute for a single file and the
 109`core.eol` configuration variable for all text files.
 110
 111Set::
 112
 113        Setting the `text` attribute on a path enables end-of-line
 114        normalization and marks the path as a text file.  End-of-line
 115        conversion takes place without guessing the content type.
 116
 117Unset::
 118
 119        Unsetting the `text` attribute on a path tells git not to
 120        attempt any end-of-line conversion upon checkin or checkout.
 121
 122Set to string value "auto"::
 123
 124        When `text` is set to "auto", the path is marked for automatic
 125        end-of-line normalization.  If git decides that the content is
 126        text, its line endings are normalized to LF on checkin.
 127
 128Unspecified::
 129
 130        If the `text` attribute is unspecified, git uses the
 131        `core.autocrlf` configuration variable to determine if the
 132        file should be converted.
 133
 134Any other value causes git to act as if `text` has been left
 135unspecified.
 136
 137`eol`
 138^^^^^
 139
 140This attribute sets a specific line-ending style to be used in the
 141working directory.  It enables end-of-line normalization without any
 142content checks, effectively setting the `text` attribute.
 143
 144Set to string value "crlf"::
 145
 146        This setting forces git to normalize line endings for this
 147        file on checkin and convert them to CRLF when the file is
 148        checked out.
 149
 150Set to string value "lf"::
 151
 152        This setting forces git to normalize line endings to LF on
 153        checkin and prevents conversion to CRLF when the file is
 154        checked out.
 155
 156Backwards compatibility with `crlf` attribute
 157^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 158
 159For backwards compatibility, the `crlf` attribute is interpreted as
 160follows:
 161
 162------------------------
 163crlf            text
 164-crlf           -text
 165crlf=input      eol=lf
 166------------------------
 167
 168End-of-line conversion
 169^^^^^^^^^^^^^^^^^^^^^^
 170
 171While git normally leaves file contents alone, it can be configured to
 172normalize line endings to LF in the repository and, optionally, to
 173convert them to CRLF when files are checked out.
 174
 175Here is an example that will make git normalize .txt, .vcproj and .sh
 176files, ensure that .vcproj files have CRLF and .sh files have LF in
 177the working directory, and prevent .jpg files from being normalized
 178regardless of their content.
 179
 180------------------------
 181*.txt           text
 182*.vcproj        eol=crlf
 183*.sh            eol=lf
 184*.jpg           -text
 185------------------------
 186
 187Other source code management systems normalize all text files in their
 188repositories, and there are two ways to enable similar automatic
 189normalization in git.
 190
 191If you simply want to have CRLF line endings in your working directory
 192regardless of the repository you are working with, you can set the
 193config variable "core.autocrlf" without changing any attributes.
 194
 195------------------------
 196[core]
 197        autocrlf = true
 198------------------------
 199
 200This does not force normalization of all text files, but does ensure
 201that text files that you introduce to the repository have their line
 202endings normalized to LF when they are added, and that files that are
 203already normalized in the repository stay normalized.
 204
 205If you want to interoperate with a source code management system that
 206enforces end-of-line normalization, or you simply want all text files
 207in your repository to be normalized, you should instead set the `text`
 208attribute to "auto" for _all_ files.
 209
 210------------------------
 211*       text=auto
 212------------------------
 213
 214This ensures that all files that git considers to be text will have
 215normalized (LF) line endings in the repository.  The `core.eol`
 216configuration variable controls which line endings git will use for
 217normalized files in your working directory; the default is to use the
 218native line ending for your platform, or CRLF if `core.autocrlf` is
 219set.
 220
 221NOTE: When `text=auto` normalization is enabled in an existing
 222repository, any text files containing CRLFs should be normalized.  If
 223they are not they will be normalized the next time someone tries to
 224change them, causing unfortunate misattribution.  From a clean working
 225directory:
 226
 227-------------------------------------------------
 228$ echo "* text=auto" >>.gitattributes
 229$ rm .git/index     # Remove the index to force git to
 230$ git reset         # re-scan the working directory
 231$ git status        # Show files that will be normalized
 232$ git add -u
 233$ git add .gitattributes
 234$ git commit -m "Introduce end-of-line normalization"
 235-------------------------------------------------
 236
 237If any files that should not be normalized show up in 'git status',
 238unset their `text` attribute before running 'git add -u'.
 239
 240------------------------
 241manual.pdf      -text
 242------------------------
 243
 244Conversely, text files that git does not detect can have normalization
 245enabled manually.
 246
 247------------------------
 248weirdchars.txt  text
 249------------------------
 250
 251If `core.safecrlf` is set to "true" or "warn", git verifies if
 252the conversion is reversible for the current setting of
 253`core.autocrlf`.  For "true", git rejects irreversible
 254conversions; for "warn", git only prints a warning but accepts
 255an irreversible conversion.  The safety triggers to prevent such
 256a conversion done to the files in the work tree, but there are a
 257few exceptions.  Even though...
 258
 259- 'git add' itself does not touch the files in the work tree, the
 260  next checkout would, so the safety triggers;
 261
 262- 'git apply' to update a text file with a patch does touch the files
 263  in the work tree, but the operation is about text files and CRLF
 264  conversion is about fixing the line ending inconsistencies, so the
 265  safety does not trigger;
 266
 267- 'git diff' itself does not touch the files in the work tree, it is
 268  often run to inspect the changes you intend to next 'git add'.  To
 269  catch potential problems early, safety triggers.
 270
 271
 272`ident`
 273^^^^^^^
 274
 275When the attribute `ident` is set for a path, git replaces
 276`$Id$` in the blob object with `$Id:`, followed by the
 27740-character hexadecimal blob object name, followed by a dollar
 278sign `$` upon checkout.  Any byte sequence that begins with
 279`$Id:` and ends with `$` in the worktree file is replaced
 280with `$Id$` upon check-in.
 281
 282
 283`filter`
 284^^^^^^^^
 285
 286A `filter` attribute can be set to a string value that names a
 287filter driver specified in the configuration.
 288
 289A filter driver consists of a `clean` command and a `smudge`
 290command, either of which can be left unspecified.  Upon
 291checkout, when the `smudge` command is specified, the command is
 292fed the blob object from its standard input, and its standard
 293output is used to update the worktree file.  Similarly, the
 294`clean` command is used to convert the contents of worktree file
 295upon checkin.
 296
 297A missing filter driver definition in the config is not an error
 298but makes the filter a no-op passthru.
 299
 300The content filtering is done to massage the content into a
 301shape that is more convenient for the platform, filesystem, and
 302the user to use.  The key phrase here is "more convenient" and not
 303"turning something unusable into usable".  In other words, the
 304intent is that if someone unsets the filter driver definition,
 305or does not have the appropriate filter program, the project
 306should still be usable.
 307
 308For example, in .gitattributes, you would assign the `filter`
 309attribute for paths.
 310
 311------------------------
 312*.c     filter=indent
 313------------------------
 314
 315Then you would define a "filter.indent.clean" and "filter.indent.smudge"
 316configuration in your .git/config to specify a pair of commands to
 317modify the contents of C programs when the source files are checked
 318in ("clean" is run) and checked out (no change is made because the
 319command is "cat").
 320
 321------------------------
 322[filter "indent"]
 323        clean = indent
 324        smudge = cat
 325------------------------
 326
 327For best results, `clean` should not alter its output further if it is
 328run twice ("clean->clean" should be equivalent to "clean"), and
 329multiple `smudge` commands should not alter `clean`'s output
 330("smudge->smudge->clean" should be equivalent to "clean").  See the
 331section on merging below.
 332
 333The "indent" filter is well-behaved in this regard: it will not modify
 334input that is already correctly indented.  In this case, the lack of a
 335smudge filter means that the clean filter _must_ accept its own output
 336without modifying it.
 337
 338
 339Interaction between checkin/checkout attributes
 340^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 341
 342In the check-in codepath, the worktree file is first converted
 343with `filter` driver (if specified and corresponding driver
 344defined), then the result is processed with `ident` (if
 345specified), and then finally with `text` (again, if specified
 346and applicable).
 347
 348In the check-out codepath, the blob content is first converted
 349with `text`, and then `ident` and fed to `filter`.
 350
 351
 352Merging branches with differing checkin/checkout attributes
 353^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 354
 355If you have added attributes to a file that cause the canonical
 356repository format for that file to change, such as adding a
 357clean/smudge filter or text/eol/ident attributes, merging anything
 358where the attribute is not in place would normally cause merge
 359conflicts.
 360
 361To prevent these unnecessary merge conflicts, git can be told to run a
 362virtual check-out and check-in of all three stages of a file when
 363resolving a three-way merge by setting the `merge.renormalize`
 364configuration variable.  This prevents changes caused by check-in
 365conversion from causing spurious merge conflicts when a converted file
 366is merged with an unconverted file.
 367
 368As long as a "smudge->clean" results in the same output as a "clean"
 369even on files that are already smudged, this strategy will
 370automatically resolve all filter-related conflicts.  Filters that do
 371not act in this way may cause additional merge conflicts that must be
 372resolved manually.
 373
 374
 375Generating diff text
 376~~~~~~~~~~~~~~~~~~~~
 377
 378`diff`
 379^^^^^^
 380
 381The attribute `diff` affects how 'git' generates diffs for particular
 382files. It can tell git whether to generate a textual patch for the path
 383or to treat the path as a binary file.  It can also affect what line is
 384shown on the hunk header `@@ -k,l +n,m @@` line, tell git to use an
 385external command to generate the diff, or ask git to convert binary
 386files to a text format before generating the diff.
 387
 388Set::
 389
 390        A path to which the `diff` attribute is set is treated
 391        as text, even when they contain byte values that
 392        normally never appear in text files, such as NUL.
 393
 394Unset::
 395
 396        A path to which the `diff` attribute is unset will
 397        generate `Binary files differ` (or a binary patch, if
 398        binary patches are enabled).
 399
 400Unspecified::
 401
 402        A path to which the `diff` attribute is unspecified
 403        first gets its contents inspected, and if it looks like
 404        text, it is treated as text.  Otherwise it would
 405        generate `Binary files differ`.
 406
 407String::
 408
 409        Diff is shown using the specified diff driver.  Each driver may
 410        specify one or more options, as described in the following
 411        section. The options for the diff driver "foo" are defined
 412        by the configuration variables in the "diff.foo" section of the
 413        git config file.
 414
 415
 416Defining an external diff driver
 417^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 418
 419The definition of a diff driver is done in `gitconfig`, not
 420`gitattributes` file, so strictly speaking this manual page is a
 421wrong place to talk about it.  However...
 422
 423To define an external diff driver `jcdiff`, add a section to your
 424`$GIT_DIR/config` file (or `$HOME/.gitconfig` file) like this:
 425
 426----------------------------------------------------------------
 427[diff "jcdiff"]
 428        command = j-c-diff
 429----------------------------------------------------------------
 430
 431When git needs to show you a diff for the path with `diff`
 432attribute set to `jcdiff`, it calls the command you specified
 433with the above configuration, i.e. `j-c-diff`, with 7
 434parameters, just like `GIT_EXTERNAL_DIFF` program is called.
 435See linkgit:git[1] for details.
 436
 437
 438Defining a custom hunk-header
 439^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 440
 441Each group of changes (called a "hunk") in the textual diff output
 442is prefixed with a line of the form:
 443
 444        @@ -k,l +n,m @@ TEXT
 445
 446This is called a 'hunk header'.  The "TEXT" portion is by default a line
 447that begins with an alphabet, an underscore or a dollar sign; this
 448matches what GNU 'diff -p' output uses.  This default selection however
 449is not suited for some contents, and you can use a customized pattern
 450to make a selection.
 451
 452First, in .gitattributes, you would assign the `diff` attribute
 453for paths.
 454
 455------------------------
 456*.tex   diff=tex
 457------------------------
 458
 459Then, you would define a "diff.tex.xfuncname" configuration to
 460specify a regular expression that matches a line that you would
 461want to appear as the hunk header "TEXT". Add a section to your
 462`$GIT_DIR/config` file (or `$HOME/.gitconfig` file) like this:
 463
 464------------------------
 465[diff "tex"]
 466        xfuncname = "^(\\\\(sub)*section\\{.*)$"
 467------------------------
 468
 469Note.  A single level of backslashes are eaten by the
 470configuration file parser, so you would need to double the
 471backslashes; the pattern above picks a line that begins with a
 472backslash, and zero or more occurrences of `sub` followed by
 473`section` followed by open brace, to the end of line.
 474
 475There are a few built-in patterns to make this easier, and `tex`
 476is one of them, so you do not have to write the above in your
 477configuration file (you still need to enable this with the
 478attribute mechanism, via `.gitattributes`).  The following built in
 479patterns are available:
 480
 481- `bibtex` suitable for files with BibTeX coded references.
 482
 483- `cpp` suitable for source code in the C and C++ languages.
 484
 485- `csharp` suitable for source code in the C# language.
 486
 487- `fortran` suitable for source code in the Fortran language.
 488
 489- `html` suitable for HTML/XHTML documents.
 490
 491- `java` suitable for source code in the Java language.
 492
 493- `objc` suitable for source code in the Objective-C language.
 494
 495- `pascal` suitable for source code in the Pascal/Delphi language.
 496
 497- `php` suitable for source code in the PHP language.
 498
 499- `python` suitable for source code in the Python language.
 500
 501- `ruby` suitable for source code in the Ruby language.
 502
 503- `tex` suitable for source code for LaTeX documents.
 504
 505
 506Customizing word diff
 507^^^^^^^^^^^^^^^^^^^^^
 508
 509You can customize the rules that `git diff --word-diff` uses to
 510split words in a line, by specifying an appropriate regular expression
 511in the "diff.*.wordRegex" configuration variable.  For example, in TeX
 512a backslash followed by a sequence of letters forms a command, but
 513several such commands can be run together without intervening
 514whitespace.  To separate them, use a regular expression in your
 515`$GIT_DIR/config` file (or `$HOME/.gitconfig` file) like this:
 516
 517------------------------
 518[diff "tex"]
 519        wordRegex = "\\\\[a-zA-Z]+|[{}]|\\\\.|[^\\{}[:space:]]+"
 520------------------------
 521
 522A built-in pattern is provided for all languages listed in the
 523previous section.
 524
 525
 526Performing text diffs of binary files
 527^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 528
 529Sometimes it is desirable to see the diff of a text-converted
 530version of some binary files. For example, a word processor
 531document can be converted to an ASCII text representation, and
 532the diff of the text shown. Even though this conversion loses
 533some information, the resulting diff is useful for human
 534viewing (but cannot be applied directly).
 535
 536The `textconv` config option is used to define a program for
 537performing such a conversion. The program should take a single
 538argument, the name of a file to convert, and produce the
 539resulting text on stdout.
 540
 541For example, to show the diff of the exif information of a
 542file instead of the binary information (assuming you have the
 543exif tool installed), add the following section to your
 544`$GIT_DIR/config` file (or `$HOME/.gitconfig` file):
 545
 546------------------------
 547[diff "jpg"]
 548        textconv = exif
 549------------------------
 550
 551NOTE: The text conversion is generally a one-way conversion;
 552in this example, we lose the actual image contents and focus
 553just on the text data. This means that diffs generated by
 554textconv are _not_ suitable for applying. For this reason,
 555only `git diff` and the `git log` family of commands (i.e.,
 556log, whatchanged, show) will perform text conversion. `git
 557format-patch` will never generate this output. If you want to
 558send somebody a text-converted diff of a binary file (e.g.,
 559because it quickly conveys the changes you have made), you
 560should generate it separately and send it as a comment _in
 561addition to_ the usual binary diff that you might send.
 562
 563Because text conversion can be slow, especially when doing a
 564large number of them with `git log -p`, git provides a mechanism
 565to cache the output and use it in future diffs.  To enable
 566caching, set the "cachetextconv" variable in your diff driver's
 567config. For example:
 568
 569------------------------
 570[diff "jpg"]
 571        textconv = exif
 572        cachetextconv = true
 573------------------------
 574
 575This will cache the result of running "exif" on each blob
 576indefinitely. If you change the textconv config variable for a
 577diff driver, git will automatically invalidate the cache entries
 578and re-run the textconv filter. If you want to invalidate the
 579cache manually (e.g., because your version of "exif" was updated
 580and now produces better output), you can remove the cache
 581manually with `git update-ref -d refs/notes/textconv/jpg` (where
 582"jpg" is the name of the diff driver, as in the example above).
 583
 584Performing a three-way merge
 585~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 586
 587`merge`
 588^^^^^^^
 589
 590The attribute `merge` affects how three versions of a file is
 591merged when a file-level merge is necessary during `git merge`,
 592and other commands such as `git revert` and `git cherry-pick`.
 593
 594Set::
 595
 596        Built-in 3-way merge driver is used to merge the
 597        contents in a way similar to 'merge' command of `RCS`
 598        suite.  This is suitable for ordinary text files.
 599
 600Unset::
 601
 602        Take the version from the current branch as the
 603        tentative merge result, and declare that the merge has
 604        conflicts.  This is suitable for binary files that does
 605        not have a well-defined merge semantics.
 606
 607Unspecified::
 608
 609        By default, this uses the same built-in 3-way merge
 610        driver as is the case the `merge` attribute is set.
 611        However, `merge.default` configuration variable can name
 612        different merge driver to be used for paths to which the
 613        `merge` attribute is unspecified.
 614
 615String::
 616
 617        3-way merge is performed using the specified custom
 618        merge driver.  The built-in 3-way merge driver can be
 619        explicitly specified by asking for "text" driver; the
 620        built-in "take the current branch" driver can be
 621        requested with "binary".
 622
 623
 624Built-in merge drivers
 625^^^^^^^^^^^^^^^^^^^^^^
 626
 627There are a few built-in low-level merge drivers defined that
 628can be asked for via the `merge` attribute.
 629
 630text::
 631
 632        Usual 3-way file level merge for text files.  Conflicted
 633        regions are marked with conflict markers `<<<<<<<`,
 634        `=======` and `>>>>>>>`.  The version from your branch
 635        appears before the `=======` marker, and the version
 636        from the merged branch appears after the `=======`
 637        marker.
 638
 639binary::
 640
 641        Keep the version from your branch in the work tree, but
 642        leave the path in the conflicted state for the user to
 643        sort out.
 644
 645union::
 646
 647        Run 3-way file level merge for text files, but take
 648        lines from both versions, instead of leaving conflict
 649        markers.  This tends to leave the added lines in the
 650        resulting file in random order and the user should
 651        verify the result. Do not use this if you do not
 652        understand the implications.
 653
 654
 655Defining a custom merge driver
 656^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 657
 658The definition of a merge driver is done in the `.git/config`
 659file, not in the `gitattributes` file, so strictly speaking this
 660manual page is a wrong place to talk about it.  However...
 661
 662To define a custom merge driver `filfre`, add a section to your
 663`$GIT_DIR/config` file (or `$HOME/.gitconfig` file) like this:
 664
 665----------------------------------------------------------------
 666[merge "filfre"]
 667        name = feel-free merge driver
 668        driver = filfre %O %A %B
 669        recursive = binary
 670----------------------------------------------------------------
 671
 672The `merge.*.name` variable gives the driver a human-readable
 673name.
 674
 675The `merge.*.driver` variable's value is used to construct a
 676command to run to merge ancestor's version (`%O`), current
 677version (`%A`) and the other branches' version (`%B`).  These
 678three tokens are replaced with the names of temporary files that
 679hold the contents of these versions when the command line is
 680built. Additionally, %L will be replaced with the conflict marker
 681size (see below).
 682
 683The merge driver is expected to leave the result of the merge in
 684the file named with `%A` by overwriting it, and exit with zero
 685status if it managed to merge them cleanly, or non-zero if there
 686were conflicts.
 687
 688The `merge.*.recursive` variable specifies what other merge
 689driver to use when the merge driver is called for an internal
 690merge between common ancestors, when there are more than one.
 691When left unspecified, the driver itself is used for both
 692internal merge and the final merge.
 693
 694
 695`conflict-marker-size`
 696^^^^^^^^^^^^^^^^^^^^^^
 697
 698This attribute controls the length of conflict markers left in
 699the work tree file during a conflicted merge.  Only setting to
 700the value to a positive integer has any meaningful effect.
 701
 702For example, this line in `.gitattributes` can be used to tell the merge
 703machinery to leave much longer (instead of the usual 7-character-long)
 704conflict markers when merging the file `Documentation/git-merge.txt`
 705results in a conflict.
 706
 707------------------------
 708Documentation/git-merge.txt     conflict-marker-size=32
 709------------------------
 710
 711
 712Checking whitespace errors
 713~~~~~~~~~~~~~~~~~~~~~~~~~~
 714
 715`whitespace`
 716^^^^^^^^^^^^
 717
 718The `core.whitespace` configuration variable allows you to define what
 719'diff' and 'apply' should consider whitespace errors for all paths in
 720the project (See linkgit:git-config[1]).  This attribute gives you finer
 721control per path.
 722
 723Set::
 724
 725        Notice all types of potential whitespace errors known to git.
 726
 727Unset::
 728
 729        Do not notice anything as error.
 730
 731Unspecified::
 732
 733        Use the value of `core.whitespace` configuration variable to
 734        decide what to notice as error.
 735
 736String::
 737
 738        Specify a comma separate list of common whitespace problems to
 739        notice in the same format as `core.whitespace` configuration
 740        variable.
 741
 742
 743Creating an archive
 744~~~~~~~~~~~~~~~~~~~
 745
 746`export-ignore`
 747^^^^^^^^^^^^^^^
 748
 749Files and directories with the attribute `export-ignore` won't be added to
 750archive files.
 751
 752`export-subst`
 753^^^^^^^^^^^^^^
 754
 755If the attribute `export-subst` is set for a file then git will expand
 756several placeholders when adding this file to an archive.  The
 757expansion depends on the availability of a commit ID, i.e., if
 758linkgit:git-archive[1] has been given a tree instead of a commit or a
 759tag then no replacement will be done.  The placeholders are the same
 760as those for the option `--pretty=format:` of linkgit:git-log[1],
 761except that they need to be wrapped like this: `$Format:PLACEHOLDERS$`
 762in the file.  E.g. the string `$Format:%H$` will be replaced by the
 763commit hash.
 764
 765
 766Packing objects
 767~~~~~~~~~~~~~~~
 768
 769`delta`
 770^^^^^^^
 771
 772Delta compression will not be attempted for blobs for paths with the
 773attribute `delta` set to false.
 774
 775
 776Viewing files in GUI tools
 777~~~~~~~~~~~~~~~~~~~~~~~~~~
 778
 779`encoding`
 780^^^^^^^^^^
 781
 782The value of this attribute specifies the character encoding that should
 783be used by GUI tools (e.g. linkgit:gitk[1] and linkgit:git-gui[1]) to
 784display the contents of the relevant file. Note that due to performance
 785considerations linkgit:gitk[1] does not use this attribute unless you
 786manually enable per-file encodings in its options.
 787
 788If this attribute is not set or has an invalid value, the value of the
 789`gui.encoding` configuration variable is used instead
 790(See linkgit:git-config[1]).
 791
 792
 793USING ATTRIBUTE MACROS
 794----------------------
 795
 796You do not want any end-of-line conversions applied to, nor textual diffs
 797produced for, any binary file you track.  You would need to specify e.g.
 798
 799------------
 800*.jpg -text -diff
 801------------
 802
 803but that may become cumbersome, when you have many attributes.  Using
 804attribute macros, you can specify groups of attributes set or unset at
 805the same time.  The system knows a built-in attribute macro, `binary`:
 806
 807------------
 808*.jpg binary
 809------------
 810
 811which is equivalent to the above.  Note that the attribute macros can only
 812be "Set" (see the above example that sets "binary" macro as if it were an
 813ordinary attribute --- setting it in turn unsets "text" and "diff").
 814
 815
 816DEFINING ATTRIBUTE MACROS
 817-------------------------
 818
 819Custom attribute macros can be defined only in the `.gitattributes` file
 820at the toplevel (i.e. not in any subdirectory).  The built-in attribute
 821macro "binary" is equivalent to:
 822
 823------------
 824[attr]binary -diff -text
 825------------
 826
 827
 828EXAMPLE
 829-------
 830
 831If you have these three `gitattributes` file:
 832
 833----------------------------------------------------------------
 834(in $GIT_DIR/info/attributes)
 835
 836a*      foo !bar -baz
 837
 838(in .gitattributes)
 839abc     foo bar baz
 840
 841(in t/.gitattributes)
 842ab*     merge=filfre
 843abc     -foo -bar
 844*.c     frotz
 845----------------------------------------------------------------
 846
 847the attributes given to path `t/abc` are computed as follows:
 848
 8491. By examining `t/.gitattributes` (which is in the same
 850   directory as the path in question), git finds that the first
 851   line matches.  `merge` attribute is set.  It also finds that
 852   the second line matches, and attributes `foo` and `bar`
 853   are unset.
 854
 8552. Then it examines `.gitattributes` (which is in the parent
 856   directory), and finds that the first line matches, but
 857   `t/.gitattributes` file already decided how `merge`, `foo`
 858   and `bar` attributes should be given to this path, so it
 859   leaves `foo` and `bar` unset.  Attribute `baz` is set.
 860
 8613. Finally it examines `$GIT_DIR/info/attributes`.  This file
 862   is used to override the in-tree settings.  The first line is
 863   a match, and `foo` is set, `bar` is reverted to unspecified
 864   state, and `baz` is unset.
 865
 866As the result, the attributes assignment to `t/abc` becomes:
 867
 868----------------------------------------------------------------
 869foo     set to true
 870bar     unspecified
 871baz     set to false
 872merge   set to string value "filfre"
 873frotz   unspecified
 874----------------------------------------------------------------
 875
 876
 877
 878GIT
 879---
 880Part of the linkgit:git[1] suite