Provided by: git-man_1.9.1-1ubuntu0.10_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. When the pattern matches the
path in question, the attributes listed on the line are given to the path.
Each attribute can be in one of these states for a given path:
Set
The path has the attribute with special value "true"; this is specified by listing only the name of
the attribute in the attribute list.
Unset
The path has the attribute with special value "false"; this is specified by listing the name of the
attribute prefixed with a dash - in the attribute list.
Set to a value
The path has the attribute with specified string value; this is specified by listing the name of the
attribute followed by an equal sign = and its value in the attribute list.
Unspecified
No pattern matches the path, and nothing says if the path has or does not have the attribute, the
attribute for the path is said to be Unspecified.
When more than one pattern matches the path, a later line overrides an earlier line. This overriding is
done per attribute. The rules how the pattern matches paths are the same as in .gitignore files; see
gitignore(5). Unlike .gitignore, negative patterns are forbidden.
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 an setting of an attribute for a path to Unspecified state. This can
be done by listing the name of the attribute prefixed with an exclamation point !.
EFFECTS
Certain operations by Git can be influenced by assigning particular attributes to a path. Currently, the
following operations are attributes-aware.
Checking-out and checking-in
These attributes affect how the contents stored in the repository are copied to the working tree files
when commands such as git checkout and git merge run. They also affect how Git stores the contents you
prepare in the working tree in the repository upon git add and git commit.
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.
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 normalization. If Git
decides that the content is text, its line endings are normalized to LF on checkin.
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 normalization without any content checks, effectively setting the text attribute.
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.
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.
*.txt text
*.vcproj eol=crlf
*.sh eol=lf
*.jpg -text
Other source code management systems normalize all text files in their repositories, and there are
two ways to enable similar automatic normalization in Git.
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 changing any
attributes.
[core]
autocrlf = true
This does not force normalization of all 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 interoperate with a source code management system that enforces end-of-line
normalization, or you simply want all text files in your repository to be normalized, you should
instead set the text attribute to "auto" for all files.
* text=auto
This ensures that all files that Git considers to be text will have normalized (LF) line endings in
the repository. The core.eol configuration variable controls which line endings Git will use for
normalized files in your working directory; the default is to use the native line ending for your
platform, or CRLF if core.autocrlf is set.
Note
When text=auto normalization is enabled in an existing repository, any text files containing
CRLFs should be normalized. If they are not they will be normalized the next time someone tries
to change them, causing unfortunate misattribution. From a clean working directory:
$ echo "* text=auto" >>.gitattributes
$ rm .git/index # Remove the index to force Git to
$ git reset # re-scan the working directory
$ git status # Show files that will be normalized
$ git add -u
$ git add .gitattributes
$ 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.
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.
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.
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
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, 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:
• ada suitable for source code in the Ada language.
• 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.
• fortran suitable for source code in the Fortran language.
• html suitable for HTML/XHTML documents.
• java suitable for source code in the Java language.
• matlab suitable for source code in the MATLAB language.
• 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.
• 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
recursive = binary
The merge.*.name variable gives the driver a human-readable name.
The ‘merge.*.driver` variable’s value is used to construct a command to run to merge ancestor’s
version (%O), current version (%A) and the other branches’ version (%B). These three tokens are
replaced with the names of temporary files that hold the contents of these versions when the command
line is built. Additionally, %L will be replaced with the conflict marker size (see below).
The merge driver is expected to leave the result of the merge in the file named with %A by
overwriting it, and exit with zero status if it managed to merge them cleanly, or non-zero if there
were conflicts.
The merge.*.recursive variable specifies what other merge driver to use when the merge driver is
called for an internal merge between common ancestors, when there are more than one. When left
unspecified, the driver itself is used for both internal merge and the final merge.
conflict-marker-size
This attribute controls the length of conflict markers left in the work tree file during a conflicted
merge. Only setting to the value to a positive integer has any meaningful effect.
For example, this line in .gitattributes can be used to tell the merge machinery to leave much longer
(instead of the usual 7-character-long) conflict markers when merging the file
Documentation/git-merge.txt results in a conflict.
Documentation/git-merge.txt conflict-marker-size=32
Checking whitespace errors
whitespace
The core.whitespace configuration variable allows you to define what diff and apply should consider
whitespace errors for all paths in the project (See git-config(1)). This attribute gives you finer
control per path.
Set
Notice all types of potential whitespace errors known to Git. 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
EXAMPLE
If you have these three gitattributes file:
(in $GIT_DIR/info/attributes)
a* foo !bar -baz
(in .gitattributes)
abc foo bar baz
(in t/.gitattributes)
ab* merge=filfre
abc -foo -bar
*.c frotz
the attributes given to path t/abc are computed as follows:
1. By examining t/.gitattributes (which is in the same directory as the path in question), Git finds
that the first line matches. merge attribute is set. It also finds that the second line matches, and
attributes foo and bar are unset.
2. Then it examines .gitattributes (which is in the parent directory), and finds that the first line
matches, but t/.gitattributes file already decided how merge, foo and bar attributes should be given
to this path, so it leaves foo and bar unset. Attribute baz is set.
3. Finally it examines $GIT_DIR/info/attributes. This file is used to override the in-tree settings. The
first line is a match, and foo is set, bar is reverted to unspecified state, and baz is unset.
As the result, the attributes assignment to t/abc becomes:
foo set to true
bar unspecified
baz set to false
merge set to string value "filfre"
frotz unspecified
SEE ALSO
git-check-attr(1).
GIT
Part of the git(1) suite