GITATTRIBUTES(5)



GITATTRIBUTES(5)                  Git Manual                  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 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 user's 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 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. 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

           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 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 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

           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 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"]
                       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.

               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
               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 "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
           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 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 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   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.

           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   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 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 driver's config. For example:

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

           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 Git's 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 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 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

           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.

           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
               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 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 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

EXAMPLES
       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

SEE ALSO
       git-check-attr(1).

GIT
       Part of the git(1) suite

Git 2.27.0                        06/01/2020                  GITATTRIBUTES(5)

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