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 !.

RESERVED BUILTIN_* ATTRIBUTES
builtin_* is a reserved namespace for builtin attribute values. Any
user defined attributes under this namespace will be ignored and
trigger a warning.

builtin_objectmode
This attribute is for filtering files by their file bit modes (40000,
120000, 160000, 100755, 100644). e.g.
:(attr:builtin_objectmode=160000). You may also check these values
with git check-attr builtin_objectmode -- <file>. If the object is
not in the index git check-attr --cached will return unspecified.

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 marks the path as a text file, which enables
end-of-line conversion: When a matching file is added to the
index, the file's line endings are normalized to LF in the index.
Conversely, when the file is copied from the index to the working
directory, its line endings may be converted from LF to CRLF
depending on the eol attribute, the Git config, and the platform
(see explanation of eol below).

Set
Setting the text attribute on a path enables end-of-line
conversion on checkin and checkout as described above. Line
endings are normalized to LF in the index every time the file
is checked in, even if the file was previously added to Git
with CRLF line endings.

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", Git decides by itself whether the
file is text or binary. If it is text and the file was not
already in Git with CRLF endings, line endings are converted
on checkin and checkout as described above. Otherwise, no
conversion is done on checkin or checkout.

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 marks a path to use a specific line-ending style
in the working tree when it is checked out. It has effect only if
text or text=auto is set (see above), but specifying eol
automatically sets text if text was left unspecified.

Set to string value "crlf"
This setting converts the file's line endings in the working
directory to CRLF when the file is checked out.

Set to string value "lf"
This setting uses the same line endings in the working
directory as in the index when the file is checked out.

Unspecified
If the eol attribute is unspecified for a file, its line
endings in the working directory are determined by the
core.autocrlf or core.eol configuration variable (see the
definitions of those options in git-config(1)). If text is
set but neither of those variables is, the default is
eol=crlf on Windows and eol=lf on all other platforms.

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.

If the program is able to ignore certain changes (similar to git
diff --ignore-space-change), then also set the option
trustExitCode to true. It is then expected to return exit code 1
if it finds significant changes and 0 if it doesn't.

Setting the internal diff algorithm

The diff algorithm can be set through the diff.algorithm config
key, but sometimes it may be helpful to set the diff algorithm
per path. For example, one may want to use the minimal diff
algorithm for .json files, and the histogram for .c files, and so
on without having to pass in the algorithm through the command
line each time.

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

*.json diff=<name>

Then, define a "diff.<name>.algorithm" configuration to specify
the diff algorithm, choosing from myers, patience, minimal, or
histogram.

[diff "<name>"]
algorithm = histogram

This diff algorithm applies to user facing diff output like
git-diff(1), git-show(1) and is used for the --stat output as
well. The merge machinery will not use the diff algorithm set
through this method.

Note

If diff.<name>.command is defined for path with the
diff=<name> attribute, it is executed as an external diff
driver (see above), and adding diff.<name>.algorithm has no
effect, as the algorithm is not passed to the external diff
driver.

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 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.

+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 kotlin suitable for source code in the Kotlin 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 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 common 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. When the driver crashes (e.g. killed by SEGV), it
is expected to exit with non-zero status that are higher than
128, and in such a case, the merge results in a failure (which is
different from producing a conflict).

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. The conflict labels to
be used for the common ancestor, local head and other head can be
passed by using %S, %X and '%Y` respectively.

conflict-marker-size

This attribute controls the length of conflict markers left in
the work tree file during a conflicted merge. Only a positive
integer has a 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 separated 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. 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.

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)
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 2.48.1 2025-01-13 GITATTRIBUTES(5)