Provided by: git-man_2.48.1-0ubuntu1.1_all 
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:
• negative patterns are forbidden
• 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...
• git add itself does not touch the files in the work tree, the next checkout would, so the safety
triggers;
• 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;
• 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:
• 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.
• 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.
• 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:
• ada suitable for source code in the Ada language.
• bash suitable for source code in the Bourne-Again SHell language. Covers a superset of POSIX
shell function definitions.
• bibtex suitable for files with BibTeX coded references.
• cpp suitable for source code in the C and C++ languages.
• csharp suitable for source code in the C# language.
• css suitable for cascading style sheets.
• dts suitable for devicetree (DTS) files.
• elixir suitable for source code in the Elixir language.
• fortran suitable for source code in the Fortran language.
• fountain suitable for Fountain documents.
• golang suitable for source code in the Go language.
• html suitable for HTML/XHTML documents.
• java suitable for source code in the Java language.
• kotlin suitable for source code in the Kotlin language.
• markdown suitable for Markdown documents.
• matlab suitable for source code in the MATLAB and Octave languages.
• objc suitable for source code in the Objective-C language.
• pascal suitable for source code in the Pascal/Delphi language.
• perl suitable for source code in the Perl language.
• php suitable for source code in the PHP language.
• python suitable for source code in the Python language.
• ruby suitable for source code in the Ruby language.
• rust suitable for source code in the Rust language.
• scheme suitable for source code in the Scheme language.
• 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 07/02/2025 GITATTRIBUTES(5)