GITATTRIBUTES(5)          (08/17/2021)           GITATTRIBUTES(5)

     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. Leading and trailing whitespaces are
          ignored. Lines that begin with # are ignored. Patterns that
          begin with a double quote are quoted in C style. 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 by which the pattern matches paths are the same as

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          in .gitignore files (see gitignore(5)), with a few
          exceptions:

          +o   negative patterns are forbidden

          +o   patterns that match a directory do not recursively match
              paths inside that directory (so using the trailing-slash
              path/ syntax is pointless in an attributes file; use
              path/** instead)

          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). Finally global and
          system-wide files are considered (they have the lowest
          precedence).

          When the .gitattributes file is missing from the work tree,
          the path in the index is used as a fall-back. During
          checkout process, .gitattributes in the index is used and
          then the file in the working tree is used as a fall-back.

          If you wish to affect only a single repository (i.e., to
          assign attributes to files that are particular to one usercqs
          workflow for that repository), 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. Attributes that should
          affect all repositories for a single user should be placed
          in a file specified by the core.attributesFile configuration
          option (see git-config(1)). Its default value is
          $XDG_CONFIG_HOME/git/attributes. If $XDG_CONFIG_HOME is
          either not set or empty, $HOME/.config/git/attributes is
          used instead. Attributes for all users on a system should be
          placed in the $(prefix)/etc/gitattributes file.

          Sometimes you would need to override a 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

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          repository are copied to the working tree files when
          commands such as git switch, 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.

          text

              This attribute enables and controls end-of-line
              normalization. When a text file is normalized, its line
              endings are converted to LF in the repository. To
              control what line ending style is used in the working
              directory, use the eol attribute for a single file and
              the core.eol configuration variable for all text files.
              Note that setting core.autocrlf to true or input
              overrides core.eol (see the definitions of those options
              in git-config(1)).

              Set
                  Setting the text attribute on a path enables
                  end-of-line normalization and marks the path as a
                  text file. End-of-line conversion takes place
                  without guessing the content type.

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

              Set to string value "auto"
                  When text is set to "auto", the path is marked for
                  automatic end-of-line conversion. If Git decides
                  that the content is text, its line endings are
                  converted to LF on checkin. When the file has been
                  committed with CRLF, no conversion is done.

              Unspecified
                  If the text attribute is unspecified, Git uses the
                  core.autocrlf configuration variable to determine if
                  the file should be converted.

              Any other value causes Git to act as if text has been
              left unspecified.

          eol

              This attribute sets a specific line-ending style to be
              used in the working directory. It enables end-of-line
              conversion without any content checks, effectively
              setting the text attribute. Note that setting this
              attribute on paths which are in the index with CRLF line
              endings may make the paths to be considered dirty.

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              Adding the path to the index again will normalize the
              line endings in the index.

              Set to string value "crlf"
                  This setting forces Git to normalize line endings
                  for this file on checkin and convert them to CRLF
                  when the file is checked out.

              Set to string value "lf"
                  This setting forces Git to normalize line endings to
                  LF on checkin and prevents conversion to CRLF when
                  the file is checked out.

          Backwards compatibility with crlf attribute

              For backwards compatibility, the crlf attribute is
              interpreted as follows:

                  crlf            text
                  -crlf           -text
                  crlf=input      eol=lf

          End-of-line conversion

              While Git normally leaves file contents alone, it can be
              configured to normalize line endings to LF in the
              repository and, optionally, to convert them to CRLF when
              files are checked out.

              If you simply want to have CRLF line endings in your
              working directory regardless of the repository you are
              working with, you can set the config variable
              "core.autocrlf" without using any attributes.

                  [core]
                          autocrlf = true

              This does not force normalization of text files, but
              does ensure that text files that you introduce to the
              repository have their line endings normalized to LF when
              they are added, and that files that are already
              normalized in the repository stay normalized.

              If you want to ensure that text files that any
              contributor introduces to the repository have their line
              endings normalized, you can set the text attribute to
              "auto" for all files.

                  *       text=auto

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              The attributes allow a fine-grained control, how the
              line endings are converted. Here is an example that will
              make Git normalize .txt, .vcproj and .sh files, ensure
              that .vcproj files have CRLF and .sh files have LF in
              the working directory, and prevent .jpg files from being
              normalized regardless of their content.

                  *               text=auto
                  *.txt           text
                  *.vcproj        text eol=crlf
                  *.sh            text eol=lf
                  *.jpg           -text

                  Note

                  When text=auto conversion is enabled in a
                  cross-platform project using push and pull to a
                  central repository the text files containing CRLFs
                  should be normalized.

              From a clean working directory:

                  $ echo "* text=auto" >.gitattributes
                  $ git add --renormalize .
                  $ git status        # Show files that will be normalized
                  $ git commit -m "Introduce end-of-line normalization"

              If any files that should not be normalized show up in
              git status, unset their text attribute before running
              git add -u.

                  manual.pdf      -text

              Conversely, text files that Git does not detect can have
              normalization enabled manually.

                  weirdchars.txt  text

              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

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                  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.

          working-tree-encoding

              Git recognizes files encoded in ASCII or one of its
              supersets (e.g. UTF-8, ISO-8859-1, ...) as text files.
              Files encoded in certain other encodings (e.g. UTF-16)
              are interpreted as binary and consequently built-in Git
              text processing tools (e.g. git diff) as well as most
              Git web front ends do not visualize the contents of
              these files by default.

              In these cases you can tell Git the encoding of a file
              in the working directory with the working-tree-encoding
              attribute. If a file with this attribute is added to
              Git, then Git re-encodes the content from the specified
              encoding to UTF-8. Finally, Git stores the UTF-8 encoded
              content in its internal data structure (called "the
              index"). On checkout the content is re-encoded back to
              the specified encoding.

              Please note that using the working-tree-encoding
              attribute may have a number of pitfalls:

              +o   Alternative Git implementations (e.g. JGit or
                  libgit2) and older Git versions (as of March 2018)
                  do not support the working-tree-encoding attribute.
                  If you decide to use the working-tree-encoding
                  attribute in your repository, then it is strongly
                  recommended to ensure that all clients working with
                  the repository support it.

                  For example, Microsoft Visual Studio resources files
                  (*.rc) or PowerShell script files (*.ps1) are
                  sometimes encoded in UTF-16. If you declare *.ps1 as
                  files as UTF-16 and you add foo.ps1 with a
                  working-tree-encoding enabled Git client, then
                  foo.ps1 will be stored as UTF-8 internally. A client
                  without working-tree-encoding support will checkout
                  foo.ps1 as UTF-8 encoded file. This will typically

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                  cause trouble for the users of this file.

                  If a Git client that does not support the
                  working-tree-encoding attribute adds a new file
                  bar.ps1, then bar.ps1 will be stored "as-is"
                  internally (in this example probably as UTF-16). A
                  client with working-tree-encoding support will
                  interpret the internal contents as UTF-8 and try to
                  convert it to UTF-16 on checkout. That operation
                  will fail and cause an error.

              +o   Reencoding content to non-UTF encodings can cause
                  errors as the conversion might not be UTF-8 round
                  trip safe. If you suspect your encoding to not be
                  round trip safe, then add it to
                  core.checkRoundtripEncoding to make Git check the
                  round trip encoding (see git-config(1)). SHIFT-JIS
                  (Japanese character set) is known to have round trip
                  issues with UTF-8 and is checked by default.

              +o   Reencoding content requires resources that might
                  slow down certain Git operations (e.g git checkout
                  or git add).

              Use the working-tree-encoding attribute only if you
              cannot store a file in UTF-8 encoding and if you want
              Git to be able to process the content as text.

              As an example, use the following attributes if your
              *.ps1 files are UTF-16 encoded with byte order mark
              (BOM) and you want Git to perform automatic line ending
              conversion based on your platform.

                  *.ps1           text working-tree-encoding=UTF-16

              Use the following attributes if your *.ps1 files are
              UTF-16 little endian encoded without BOM and you want
              Git to use Windows line endings in the working directory
              (use UTF-16LE-BOM instead of UTF-16LE if you want UTF-16
              little endian with BOM). Please note, it is highly
              recommended to explicitly define the line endings with
              eol if the working-tree-encoding attribute is used to
              avoid ambiguity.

                  *.ps1           text working-tree-encoding=UTF-16LE eol=CRLF

              You can get a list of all available encodings on your
              platform with the following command:

                  iconv --list

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              If you do not know the encoding of a file, then you can
              use the file command to guess the encoding:

                  file foo.ps1

          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. By default
              these commands process only a single blob and terminate.
              If a long running process filter is used in place of
              clean and/or smudge filters, then Git can process all
              blobs with a single filter command invocation for the
              entire life of a single Git command, for example git add
              --all. If a long running process filter is configured
              then it always takes precedence over a configured single
              blob filter. See section below for the description of
              the protocol used to communicate with a process filter.

              One use of the content filtering is to massage the
              content into a shape that is more convenient for the
              platform, filesystem, and the user to use. For this mode
              of operation, 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.

              Another use of the content filtering is to store the
              content that cannot be directly used in the repository
              (e.g. a UUID that refers to the true content stored
              outside Git, or an encrypted content) and turn it into a
              usable form upon checkout (e.g. download the external

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              content, or decrypt the encrypted content).

              These two filters behave differently, and by default, a
              filter is taken as the former, massaging the contents
              into more convenient shape. A missing filter driver
              definition in the config, or a filter driver that exits
              with a non-zero status, is not an error but makes the
              filter a no-op passthru.

              You can declare that a filter turns a content that by
              itself is unusable into a usable content by setting the
              filter.<driver>.required configuration variable to true.

              Note: Whenever the clean filter is changed, the repo
              should be renormalized: $ git add --renormalize .

              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

              For best results, clean should not alter its output
              further if it is run twice ("clean->clean" should be
              equivalent to "clean"), and multiple smudge commands
              should not alter clean's output ("smudge->smudge->clean"
              should be equivalent to "clean"). See the section on
              merging below.

              The "indent" filter is well-behaved in this regard: it
              will not modify input that is already correctly
              indented. In this case, the lack of a smudge filter
              means that the clean filter must accept its own output
              without modifying it.

              If a filter must succeed in order to make the stored
              contents usable, you can declare that the filter is
              required, in the configuration:

                  [filter "crypt"]

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                          clean = openssl enc ...
                          smudge = openssl enc -d ...
                          required

              Sequence "%f" on the filter command line is replaced
              with the name of the file the filter is working on. A
              filter might use this in keyword substitution. For
              example:

                  [filter "p4"]
                          clean = git-p4-filter --clean %f
                          smudge = git-p4-filter --smudge %f

              Note that "%f" is the name of the path that is being
              worked on. Depending on the version that is being
              filtered, the corresponding file on disk may not exist,
              or may have different contents. So, smudge and clean
              commands should not try to access the file on disk, but
              only act as filters on the content provided to them on
              standard input.

          Long Running Filter Process

              If the filter command (a string value) is defined via
              filter.<driver>.process then Git can process all blobs
              with a single filter invocation for the entire life of a
              single Git command. This is achieved by using the
              long-running process protocol (described in
              technical/long-running-process-protocol.txt).

              When Git encounters the first file that needs to be
              cleaned or smudged, it starts the filter and performs
              the handshake. In the handshake, the welcome message
              sent by Git is "git-filter-client", only version 2 is
              supported, and the supported capabilities are "clean",
              "smudge", and "delay".

              Afterwards Git sends a list of "key=value" pairs
              terminated with a flush packet. The list will contain at
              least the filter command (based on the supported
              capabilities) and the pathname of the file to filter
              relative to the repository root. Right after the flush
              packet Git sends the content split in zero or more
              pkt-line packets and a flush packet to terminate
              content. Please note, that the filter must not send any
              response before it received the content and the final
              flush packet. Also note that the "value" of a
              "key=value" pair can contain the "=" character whereas
              the key would never contain that character.

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                  packet:          git> command=smudge
                  packet:          git> pathname=path/testfile.dat
                  packet:          git> 0000
                  packet:          git> CONTENT
                  packet:          git> 0000

              The filter is expected to respond with a list of
              "key=value" pairs terminated with a flush packet. If the
              filter does not experience problems then the list must
              contain a "success" status. Right after these packets
              the filter is expected to send the content in zero or
              more pkt-line packets and a flush packet at the end.
              Finally, a second list of "key=value" pairs terminated
              with a flush packet is expected. The filter can change
              the status in the second list or keep the status as is
              with an empty list. Please note that the empty list must
              be terminated with a flush packet regardless.

                  packet:          git< status=success
                  packet:          git< 0000
                  packet:          git< SMUDGED_CONTENT
                  packet:          git< 0000
                  packet:          git< 0000  # empty list, keep "status=success" unchanged!

              If the result content is empty then the filter is
              expected to respond with a "success" status and a flush
              packet to signal the empty content.

                  packet:          git< status=success
                  packet:          git< 0000
                  packet:          git< 0000  # empty content!
                  packet:          git< 0000  # empty list, keep "status=success" unchanged!

              In case the filter cannot or does not want to process
              the content, it is expected to respond with an "error"
              status.

                  packet:          git< status=error
                  packet:          git< 0000

              If the filter experiences an error during processing,
              then it can send the status "error" after the content
              was (partially or completely) sent.

                  packet:          git< status=success
                  packet:          git< 0000
                  packet:          git< HALF_WRITTEN_ERRONEOUS_CONTENT
                  packet:          git< 0000

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                  packet:          git< status=error
                  packet:          git< 0000

              In case the filter cannot or does not want to process
              the content as well as any future content for the
              lifetime of the Git process, then it is expected to
              respond with an "abort" status at any point in the
              protocol.

                  packet:          git< status=abort
                  packet:          git< 0000

              Git neither stops nor restarts the filter process in
              case the "error"/"abort" status is set. However, Git
              sets its exit code according to the
              filter.<driver>.required flag, mimicking the behavior of
              the filter.<driver>.clean / filter.<driver>.smudge
              mechanism.

              If the filter dies during the communication or does not
              adhere to the protocol then Git will stop the filter
              process and restart it with the next file that needs to
              be processed. Depending on the filter.<driver>.required
              flag Git will interpret that as error.

          Delay

              If the filter supports the "delay" capability, then Git
              can send the flag "can-delay" after the filter command
              and pathname. This flag denotes that the filter can
              delay filtering the current blob (e.g. to compensate
              network latencies) by responding with no content but
              with the status "delayed" and a flush packet.

                  packet:          git> command=smudge
                  packet:          git> pathname=path/testfile.dat
                  packet:          git> can-delay=1
                  packet:          git> 0000
                  packet:          git> CONTENT
                  packet:          git> 0000
                  packet:          git< status=delayed
                  packet:          git< 0000

              If the filter supports the "delay" capability then it
              must support the "list_available_blobs" command. If Git
              sends this command, then the filter is expected to
              return a list of pathnames representing blobs that have
              been delayed earlier and are now available. The list
              must be terminated with a flush packet followed by a

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              "success" status that is also terminated with a flush
              packet. If no blobs for the delayed paths are available,
              yet, then the filter is expected to block the response
              until at least one blob becomes available. The filter
              can tell Git that it has no more delayed blobs by
              sending an empty list. As soon as the filter responds
              with an empty list, Git stops asking. All blobs that Git
              has not received at this point are considered missing
              and will result in an error.

                  packet:          git> command=list_available_blobs
                  packet:          git> 0000
                  packet:          git< pathname=path/testfile.dat
                  packet:          git< pathname=path/otherfile.dat
                  packet:          git< 0000
                  packet:          git< status=success
                  packet:          git< 0000

              After Git received the pathnames, it will request the
              corresponding blobs again. These requests contain a
              pathname and an empty content section. The filter is
              expected to respond with the smudged content in the
              usual way as explained above.

                  packet:          git> command=smudge
                  packet:          git> pathname=path/testfile.dat
                  packet:          git> 0000
                  packet:          git> 0000  # empty content!
                  packet:          git< status=success
                  packet:          git< 0000
                  packet:          git< SMUDGED_CONTENT
                  packet:          git< 0000
                  packet:          git< 0000  # empty list, keep "status=success" unchanged!

          Example

              A long running filter demo implementation can be found
              in contrib/long-running-filter/example.pl located in the
              Git core repository. If you develop your own long
              running filter process then the GIT_TRACE_PACKET
              environment variables can be very helpful for debugging
              (see git(1)).

              Please note that you cannot use an existing
              filter.<driver>.clean or filter.<driver>.smudge command
              with filter.<driver>.process because the former two use
              a different inter process communication protocol than
              the latter one.

          Interaction between checkin/checkout attributes

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              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 text (again, if specified and applicable).

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

          Merging branches with differing checkin/checkout attributes

              If you have added attributes to a file that cause the
              canonical repository format for that file to change,
              such as adding a clean/smudge filter or text/eol/ident
              attributes, merging anything where the attribute is not
              in place would normally cause merge conflicts.

              To prevent these unnecessary merge conflicts, Git can be
              told to run a virtual check-out and check-in of all
              three stages of a file when resolving a three-way merge
              by setting the merge.renormalize configuration variable.
              This prevents changes caused by check-in conversion from
              causing spurious merge conflicts when a converted file
              is merged with an unconverted file.

              As long as a "smudge->clean" results in the same output
              as a "clean" even on files that are already smudged,
              this strategy will automatically resolve all
              filter-related conflicts. Filters that do not act in
              this way may cause additional merge conflicts that must
              be resolved manually.

        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

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                  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 and is smaller than core.bigFileThreshold,
                  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

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              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   ada suitable for source code in the Ada language.

              +o   bash suitable for source code in the Bourne-Again
                  SHell language. Covers a superset of POSIX shell
                  function definitions.

              +o   bibtex suitable for files with BibTeX coded
                  references.

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

              +o   csharp suitable for source code in the C# language.

              +o   css suitable for cascading style sheets.

              +o   dts suitable for devicetree (DTS) files.

              +o   elixir suitable for source code in the Elixir
                  language.

              +o   fortran suitable for source code in the Fortran
                  language.

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              +o   fountain suitable for Fountain documents.

              +o   golang suitable for source code in the Go language.

              +o   html suitable for HTML/XHTML documents.

              +o   java suitable for source code in the Java language.

              +o   markdown suitable for Markdown documents.

              +o   matlab suitable for source code in the MATLAB and
                  Octave languages.

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

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

              +o   perl suitable for source code in the Perl 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   rust suitable for source code in the Rust language.

              +o   scheme suitable for source code in the Scheme
                  language.

              +o   tex suitable for source code for LaTeX documents.

          Customizing word diff

              You can customize the rules that git diff --word-diff
              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

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              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.

              Because text conversion can be slow, especially when
              doing a large number of them with git log -p, Git
              provides a mechanism to cache the output and use it in
              future diffs. To enable caching, set the "cachetextconv"
              variable in your diff drivercqs config. For example:

                  [diff "jpg"]
                          textconv = exif
                          cachetextconv = true


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              This will cache the result of running "exif" on each
              blob indefinitely. If you change the textconv config
              variable for a diff driver, Git will automatically
              invalidate the cache entries and re-run the textconv
              filter. If you want to invalidate the cache manually
              (e.g., because your version of "exif" was updated and
              now produces better output), you can remove the cache
              manually with git update-ref -d refs/notes/textconv/jpg
              (where "jpg" is the name of the diff driver, as in the
              example above).

          Choosing textconv versus external diff

              If you want to show differences between binary or
              specially-formatted blobs in your repository, you can
              choose to use either an external diff command, or to use
              textconv to convert them to a diff-able text format.
              Which method you choose depends on your exact situation.

              The advantage of using an external diff command is
              flexibility. You are not bound to find line-oriented
              changes, nor is it necessary for the output to resemble
              unified diff. You are free to locate and report changes
              in the most appropriate way for your data format.

              A textconv, by comparison, is much more limiting. You
              provide a transformation of the data into a
              line-oriented text format, and Git uses its regular diff
              tools to generate the output. There are several
              advantages to choosing this method:

               1. Ease of use. It is often much simpler to write a
                  binary to text transformation than it is to perform
                  your own diff. In many cases, existing programs can
                  be used as textconv filters (e.g., exif, odt2txt).

               2. Git diff features. By performing only the
                  transformation step yourself, you can still utilize
                  many of Gitcqs diff features, including colorization,
                  word-diff, and combined diffs for merges.

               3. Caching. Textconv caching can speed up repeated
                  diffs, such as those you might trigger by running
                  git log -p.

          Marking files as binary

              Git usually guesses correctly whether a blob contains
              text or binary data by examining the beginning of the
              contents. However, sometimes you may want to override
              its decision, either because a blob contains binary data
              later in the file, or because the content, while

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              technically composed of text characters, is opaque to a
              human reader. For example, many postscript files contain
              only ASCII characters, but produce noisy and meaningless
              diffs.

              The simplest way to mark a file as binary is to unset
              the diff attribute in the .gitattributes file:

                  *.ps -diff

              This will cause Git to generate Binary files differ (or
              a binary patch, if binary patches are enabled) instead
              of a regular diff.

              However, one may also want to specify other diff driver
              attributes. For example, you might want to use textconv
              to convert postscript files to an ASCII representation
              for human viewing, but otherwise treat them as binary
              files. You cannot specify both -diff and diff=ps
              attributes. The solution is to use the diff.*.binary
              config option:

                  [diff "ps"]
                    textconv = ps2ascii
                    binary = true

        Performing a three-way merge
          merge

              The attribute merge affects how three versions of a file
              are 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 do not have a well-defined merge semantics.

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

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                  with paths for 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 %L %P
                          recursive = binary

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

              The oqmerge.*.driver` variablecqs value is used to
              construct a command to run to merge ancestorcqs version
              (%O), current version (%A) and the other branchescq
              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.

              The merge driver can learn the pathname in which the
              merged result will be stored via placeholder %P.

          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

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                  Notice all types of potential whitespace errors
                  known to Git. The tab width is taken from the value
                  of the core.whitespace configuration variable.

              Unset
                  Do not notice anything as error.

              Unspecified
                  Use the value of the 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 the
                  core.whitespace configuration variable.

        Creating an archive
          export-ignore

              Files and directories with the attribute export-ignore
              woncqt 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. However, only one
              %(describe) placeholder is expanded per archive to avoid
              denial-of-service attacks.

        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.

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              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 MACRO ATTRIBUTES
          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 -text -diff

          but that may become cumbersome, when you have many
          attributes. Using macro attributes, you can define an
          attribute that, when set, also sets or unsets a number of
          other attributes at the same time. The system knows a
          built-in macro attribute, binary:

              *.jpg binary

          Setting the "binary" attribute also unsets the "text" and
          "diff" attributes as above. Note that macro attributes can
          only be "Set", though setting one might have the effect of
          setting or unsetting other attributes or even returning
          other attributes to the "Unspecified" state.

     DEFINING MACRO ATTRIBUTES
          Custom macro attributes can be defined only in top-level
          gitattributes files ($GIT_DIR/info/attributes, the
          .gitattributes file at the top level of the working tree, or
          the global or system-wide gitattributes files), not in
          .gitattributes files in working tree subdirectories. The
          built-in macro attribute "binary" is equivalent to:

              [attr]binary -diff -merge -text

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

     EXAMPLES
          If you have these three gitattributes file:

              (in $GIT_DIR/info/attributes)

              a*      foo !bar -baz

              (in .gitattributes)

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              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

     SEE ALSO
          git-check-attr(1).

     GIT
          Part of the git(1) suite

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