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NAME

       gitattributes - defining attributes per path

SYNOPSIS

       $GIT_DIR/info/attributes, .gitattributes

DESCRIPTION

       A gitattributes file is a simple text file that gives attributes to
       pathnames.

       Each line in gitattributes file is of form:

           pattern attr1 attr2 ...

       That is, a pattern followed by an attributes list, separated by
       whitespaces. When the pattern matches the path in question, the
       attributes listed on the line are given to the path.

       Each attribute can be in one of these states for a given path:

       Set
           The path has the attribute with special value "true"; this is
           specified by listing only the name of the attribute in the
           attribute list.

       Unset
           The path has the attribute with special value "false"; this is
           specified by listing the name of the attribute prefixed with a dash
           - in the attribute list.

       Set to a value
           The path has the attribute with specified string value; this is
           specified by listing the name of the attribute followed by an equal
           sign = and its value in the attribute list.

       Unspecified
           No pattern matches the path, and nothing says if the path has or
           does not have the attribute, the attribute for the path is said to
           be Unspecified.

       When more than one pattern matches the path, a later line overrides an
       earlier line. This overriding is done per attribute. The rules how the
       pattern matches paths are the same as in .gitignore files; see
       gitignore(5).

       When deciding what attributes are assigned to a path, git consults
       $GIT_DIR/info/attributes file (which has the highest precedence),
       .gitattributes file in the same directory as the path in question, and
       its parent directories up to the toplevel of the work tree (the further
       the directory that contains .gitattributes is from the path in
       question, the lower its precedence).

       If you wish to affect only a single repository (i.e., to assign
       attributes to files that are particular to one user's workflow), then
       attributes should be placed in the $GIT_DIR/info/attributes file.
       Attributes which should be version-controlled and distributed to other
       repositories (i.e., attributes of interest to all users) should go into
       .gitattributes files.

       Sometimes you would need to override an setting of an attribute for a
       path to unspecified state. This can be done by listing the name of the
       attribute prefixed with an exclamation point !.

EFFECTS

       Certain operations by git can be influenced by assigning particular
       attributes to a path. Currently, the following operations are
       attributes-aware.

   Checking-out and checking-in
       These attributes affect how the contents stored in the repository are
       copied to the working tree files when commands such as git checkout and
       git merge run. They also affect how git stores the contents you prepare
       in the working tree in the repository upon git add and git commit.

       crlf
           This attribute controls the line-ending convention.

           Set
               Setting the crlf attribute on a path is meant to mark the path
               as a "text" file.  core.autocrlf conversion takes place without
               guessing the content type by inspection.

           Unset
               Unsetting the crlf attribute on a path tells git not to attempt
               any end-of-line conversion upon checkin or checkout.

           Unspecified
               Unspecified crlf attribute tells git to apply the core.autocrlf
               conversion when the file content looks like text.

           Set to string value "input"
               This is similar to setting the attribute to true, but also
               forces git to act as if core.autocrlf is set to input for the
               path.

           Any other value set to crlf attribute is ignored and git acts as if
           the attribute is left unspecified.

       The core.autocrlf conversion
           If the configuration variable core.autocrlf is false, no conversion
           is done.

           When core.autocrlf is true, it means that the platform wants CRLF
           line endings for files in the working tree, and you want to convert
           them back to the normal LF line endings when checking in to the
           repository.

           When core.autocrlf is set to "input", line endings are converted to
           LF upon checkin, but there is no conversion done upon checkout.

           If core.safecrlf is set to "true" or "warn", git verifies if the
           conversion is reversible for the current setting of core.autocrlf.
           For "true", git rejects irreversible conversions; for "warn", git
           only prints a warning but accepts an irreversible conversion. The
           safety triggers to prevent such a conversion done to the files in
           the work tree, but there are a few exceptions. Even though...

           o    git add itself does not touch the files in the work tree, the
               next checkout would, so the safety triggers;

           o    git apply to update a text file with a patch does touch the
               files in the work tree, but the operation is about text files
               and CRLF conversion is about fixing the line ending
               inconsistencies, so the safety does not trigger;

           o    git diff itself does not touch the files in the work tree, it
               is often run to inspect the changes you intend to next git add.
               To catch potential problems early, safety triggers.

       ident
           When the attribute ident is set for a path, git replaces $Id$ in
           the blob object with $Id:, followed by the 40-character hexadecimal
           blob object name, followed by a dollar sign $ upon checkout. Any
           byte sequence that begins with $Id: and ends with $ in the worktree
           file is replaced with $Id$ upon check-in.

       filter
           A filter attribute can be set to a string value that names a filter
           driver specified in the configuration.

           A filter driver consists of a clean command and a smudge command,
           either of which can be left unspecified. Upon checkout, when the
           smudge command is specified, the command is fed the blob object
           from its standard input, and its standard output is used to update
           the worktree file. Similarly, the clean command is used to convert
           the contents of worktree file upon checkin.

           A missing filter driver definition in the config is not an error
           but makes the filter a no-op passthru.

           The content filtering is done to massage the content into a shape
           that is more convenient for the platform, filesystem, and the user
           to use. The key phrase here is "more convenient" and not "turning
           something unusable into usable". In other words, the intent is that
           if someone unsets the filter driver definition, or does not have
           the appropriate filter program, the project should still be usable.

           For example, in .gitattributes, you would assign the filter
           attribute for paths.

               *.c     filter=indent

           Then you would define a "filter.indent.clean" and
           "filter.indent.smudge" configuration in your .git/config to specify
           a pair of commands to modify the contents of C programs when the
           source files are checked in ("clean" is run) and checked out (no
           change is made because the command is "cat").

               [filter "indent"]
                       clean = indent
                       smudge = cat

       Interaction between checkin/checkout attributes
           In the check-in codepath, the worktree file is first converted with
           filter driver (if specified and corresponding driver defined), then
           the result is processed with ident (if specified), and then finally
           with crlf (again, if specified and applicable).

           In the check-out codepath, the blob content is first converted with
           crlf, and then ident and fed to filter.

   Generating diff text
       diff
           The attribute diff affects how git generates diffs for particular
           files. It can tell git whether to generate a textual patch for the
           path or to treat the path as a binary file. It can also affect what
           line is shown on the hunk header @@ -k,l +n,m @@ line, tell git to
           use an external command to generate the diff, or ask git to convert
           binary files to a text format before generating the diff.

           Set
               A path to which the diff attribute is set is treated as text,
               even when they contain byte values that normally never appear
               in text files, such as NUL.

           Unset
               A path to which the diff attribute is unset will generate
               Binary files differ (or a binary patch, if binary patches are
               enabled).

           Unspecified
               A path to which the diff attribute is unspecified first gets
               its contents inspected, and if it looks like text, it is
               treated as text. Otherwise it would generate Binary files
               differ.

           String
               Diff is shown using the specified diff driver. Each driver may
               specify one or more options, as described in the following
               section. The options for the diff driver "foo" are defined by
               the configuration variables in the "diff.foo" section of the
               git config file.

       Defining an external diff driver
           The definition of a diff driver is done in gitconfig, not
           gitattributes file, so strictly speaking this manual page is a
           wrong place to talk about it. However...

           To define an external diff driver jcdiff, add a section to your
           $GIT_DIR/config file (or $HOME/.gitconfig file) like this:

               [diff "jcdiff"]
                       command = j-c-diff

           When git needs to show you a diff for the path with diff attribute
           set to jcdiff, it calls the command you specified with the above
           configuration, i.e. j-c-diff, with 7 parameters, just like
           GIT_EXTERNAL_DIFF program is called. See git(1) for details.

       Defining a custom hunk-header
           Each group of changes (called a "hunk") in the textual diff output
           is prefixed with a line of the form:

               @@ -k,l +n,m @@ TEXT

           This is called a hunk header. The "TEXT" portion is by default a
           line that begins with an alphabet, an underscore or a dollar sign;
           this matches what GNU diff -p output uses. This default selection
           however is not suited for some contents, and you can use a
           customized pattern to make a selection.

           First, in .gitattributes, you would assign the diff attribute for
           paths.

               *.tex   diff=tex

           Then, you would define a "diff.tex.xfuncname" configuration to
           specify a regular expression that matches a line that you would
           want to appear as the hunk header "TEXT". Add a section to your
           $GIT_DIR/config file (or $HOME/.gitconfig file) like this:

               [diff "tex"]
                       xfuncname = "^(\\\\(sub)*section\\{.*)$"

           Note. A single level of backslashes are eaten by the configuration
           file parser, so you would need to double the backslashes; the
           pattern above picks a line that begins with a backslash, and zero
           or more occurrences of sub followed by section followed by open
           brace, to the end of line.

           There are a few built-in patterns to make this easier, and tex is
           one of them, so you do not have to write the above in your
           configuration file (you still need to enable this with the
           attribute mechanism, via .gitattributes). The following built in
           patterns are available:

           o    bibtex suitable for files with BibTeX coded references.

           o    cpp suitable for source code in the C and C++ languages.

           o    html suitable for HTML/XHTML documents.

           o    java suitable for source code in the Java language.

           o    objc suitable for source code in the Objective-C language.

           o    pascal suitable for source code in the Pascal/Delphi language.

           o    php suitable for source code in the PHP language.

           o    python suitable for source code in the Python language.

           o    ruby suitable for source code in the Ruby language.

           o    tex suitable for source code for LaTeX documents.

       Customizing word diff
           You can customize the rules that git diff --color-words uses to
           split words in a line, by specifying an appropriate regular
           expression in the "diff.*.wordRegex" configuration variable. For
           example, in TeX a backslash followed by a sequence of letters forms
           a command, but several such commands can be run together without
           intervening whitespace. To separate them, use a regular expression
           in your $GIT_DIR/config file (or $HOME/.gitconfig file) like this:

               [diff "tex"]
                       wordRegex = "\\\\[a-zA-Z]+|[{}]|\\\\.|[^\\{}[:space:]]+"

           A built-in pattern is provided for all languages listed in the
           previous section.

       Performing text diffs of binary files
           Sometimes it is desirable to see the diff of a text-converted
           version of some binary files. For example, a word processor
           document can be converted to an ASCII text representation, and the
           diff of the text shown. Even though this conversion loses some
           information, the resulting diff is useful for human viewing (but
           cannot be applied directly).

           The textconv config option is used to define a program for
           performing such a conversion. The program should take a single
           argument, the name of a file to convert, and produce the resulting
           text on stdout.

           For example, to show the diff of the exif information of a file
           instead of the binary information (assuming you have the exif tool
           installed), add the following section to your $GIT_DIR/config file
           (or $HOME/.gitconfig file):

               [diff "jpg"]
                       textconv = exif

               Note
               The text conversion is generally a one-way conversion; in this
               example, we lose the actual image contents and focus just on
               the text data. This means that diffs generated by textconv are
               not suitable for applying. For this reason, only git diff and
               the git log family of commands (i.e., log, whatchanged, show)
               will perform text conversion. git format-patch will never
               generate this output. If you want to send somebody a
               text-converted diff of a binary file (e.g., because it quickly
               conveys the changes you have made), you should generate it
               separately and send it as a comment in addition to the usual
               binary diff that you might send.

   Performing a three-way merge
       merge
           The attribute merge affects how three versions of a file is merged
           when a file-level merge is necessary during git merge, and other
           commands such as git revert and git cherry-pick.

           Set
               Built-in 3-way merge driver is used to merge the contents in a
               way similar to merge command of RCS suite. This is suitable for
               ordinary text files.

           Unset
               Take the version from the current branch as the tentative merge
               result, and declare that the merge has conflicts. This is
               suitable for binary files that does not have a well-defined
               merge semantics.

           Unspecified
               By default, this uses the same built-in 3-way merge driver as
               is the case the merge attribute is set. However, merge.default
               configuration variable can name different merge driver to be
               used for paths to which the merge attribute is unspecified.

           String
               3-way merge is performed using the specified custom merge
               driver. The built-in 3-way merge driver can be explicitly
               specified by asking for "text" driver; the built-in "take the
               current branch" driver can be requested with "binary".

       Built-in merge drivers
           There are a few built-in low-level merge drivers defined that can
           be asked for via the merge attribute.

           text
               Usual 3-way file level merge for text files. Conflicted regions
               are marked with conflict markers <<<<<<<, ======= and >>>>>>>.
               The version from your branch appears before the ======= marker,
               and the version from the merged branch appears after the
               ======= marker.

           binary
               Keep the version from your branch in the work tree, but leave
               the path in the conflicted state for the user to sort out.

           union
               Run 3-way file level merge for text files, but take lines from
               both versions, instead of leaving conflict markers. This tends
               to leave the added lines in the resulting file in random order
               and the user should verify the result. Do not use this if you
               do not understand the implications.

       Defining a custom merge driver
           The definition of a merge driver is done in the .git/config file,
           not in the gitattributes file, so strictly speaking this manual
           page is a wrong place to talk about it. However...

           To define a custom merge driver filfre, add a section to your
           $GIT_DIR/config file (or $HOME/.gitconfig file) like this:

               [merge "filfre"]
                       name = feel-free merge driver
                       driver = filfre %O %A %B
                       recursive = binary

           The merge.*.name variable gives the driver a human-readable name.

           The 'merge.*.driver` variable's value is used to construct a
           command to run to merge ancestor's version (%O), current version
           (%A) and the other branches' version (%B). These three tokens are
           replaced with the names of temporary files that hold the contents
           of these versions when the command line is built. Additionally, %L
           will be replaced with the conflict marker size (see below).

           The merge driver is expected to leave the result of the merge in
           the file named with %A by overwriting it, and exit with zero status
           if it managed to merge them cleanly, or non-zero if there were
           conflicts.

           The merge.*.recursive variable specifies what other merge driver to
           use when the merge driver is called for an internal merge between
           common ancestors, when there are more than one. When left
           unspecified, the driver itself is used for both internal merge and
           the final merge.

       conflict-marker-size
           This attribute controls the length of conflict markers left in the
           work tree file during a conflicted merge. Only setting to the value
           to a positive integer has any meaningful effect.

           For example, this line in .gitattributes can be used to tell the
           merge machinery to leave much longer (instead of the usual
           7-character-long) conflict markers when merging the file
           Documentation/git-merge.txt results in a conflict.

               Documentation/git-merge.txt     conflict-marker-size=32

   Checking whitespace errors
       whitespace
           The core.whitespace configuration variable allows you to define
           what diff and apply should consider whitespace errors for all paths
           in the project (See git-config(1)). This attribute gives you finer
           control per path.

           Set
               Notice all types of potential whitespace errors known to git.

           Unset
               Do not notice anything as error.

           Unspecified
               Use the value of core.whitespace configuration variable to
               decide what to notice as error.

           String
               Specify a comma separate list of common whitespace problems to
               notice in the same format as core.whitespace configuration
               variable.

   Creating an archive
       export-ignore
           Files and directories with the attribute export-ignore won't be
           added to archive files.

       export-subst
           If the attribute export-subst is set for a file then git will
           expand several placeholders when adding this file to an archive.
           The expansion depends on the availability of a commit ID, i.e., if
           git-archive(1) has been given a tree instead of a commit or a tag
           then no replacement will be done. The placeholders are the same as
           those for the option --pretty=format: of git-log(1), except that
           they need to be wrapped like this: $Format:PLACEHOLDERS$ in the
           file. E.g. the string $Format:%H$ will be replaced by the commit
           hash.

   Packing objects
       delta
           Delta compression will not be attempted for blobs for paths with
           the attribute delta set to false.

   Viewing files in GUI tools
       encoding
           The value of this attribute specifies the character encoding that
           should be used by GUI tools (e.g. gitk(1) and git-gui(1)) to
           display the contents of the relevant file. Note that due to
           performance considerations gitk(1) does not use this attribute
           unless you manually enable per-file encodings in its options.

           If this attribute is not set or has an invalid value, the value of
           the gui.encoding configuration variable is used instead (See git-
           config(1)).

USING ATTRIBUTE MACROS

       You do not want any end-of-line conversions applied to, nor textual
       diffs produced for, any binary file you track. You would need to
       specify e.g.

           *.jpg -crlf -diff

       but that may become cumbersome, when you have many attributes. Using
       attribute macros, you can specify groups of attributes set or unset at
       the same time. The system knows a built-in attribute macro, binary:

           *.jpg binary

       which is equivalent to the above. Note that the attribute macros can
       only be "Set" (see the above example that sets "binary" macro as if it
       were an ordinary attribute --- setting it in turn unsets "crlf" and
       "diff").

DEFINING ATTRIBUTE MACROS

       Custom attribute macros can be defined only in the .gitattributes file
       at the toplevel (i.e. not in any subdirectory). The built-in attribute
       macro "binary" is equivalent to:

           [attr]binary -diff -crlf

EXAMPLE

       If you have these three gitattributes file:

           (in $GIT_DIR/info/attributes)

           a*      foo !bar -baz

           (in .gitattributes)
           abc     foo bar baz

           (in t/.gitattributes)
           ab*     merge=filfre
           abc     -foo -bar
           *.c     frotz

       the attributes given to path t/abc are computed as follows:

        1. By examining t/.gitattributes (which is in the same directory as
           the path in question), git finds that the first line matches.
           merge attribute is set. It also finds that the second line matches,
           and attributes foo and bar are unset.

        2. Then it examines .gitattributes (which is in the parent directory),
           and finds that the first line matches, but t/.gitattributes file
           already decided how merge, foo and bar attributes should be given
           to this path, so it leaves foo and bar unset. Attribute baz is set.

        3. Finally it examines $GIT_DIR/info/attributes. This file is used to
           override the in-tree settings. The first line is a match, and foo
           is set, bar is reverted to unspecified state, and baz is unset.

       As the result, the attributes assignment to t/abc becomes:

           foo     set to true
           bar     unspecified
           baz     set to false
           merge   set to string value "filfre"
           frotz   unspecified

GIT

       Part of the git(1) suite