Documentation/gitattributes.txt - git - Git at Google

 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:

 	glob	attr1 attr2 ...

 That is, a glob pattern followed by an attributes list,
 separated by whitespaces.  When the glob 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 glob pattern matches the path, and nothing says if
 	the path has or does not have the attribute.

 When more than one glob pattern matches the path, a later line
 overrides an earlier line.

 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 (the further the
 directory that contains `.gitattributes` is from the path in
 question, the lower its precedence).

 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, three operations
 are attributes-aware.

 Checking-out and checking-in
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 The attribute `crlf` affects how the contents stored in the
 repository are copied to the working tree files when commands
 such as `git checkout` and `git merge` run.  It also affects how
 git stores the contents you prepare in the working tree in the
 repository upon `git add` and `git commit`.

 Set::

 	Setting the `crlf` attribute on a path is meant to mark
 	the path as a "text" file.  'core.autocrlf' conversion
 	takes place without guessing the content type by
 	inspection.

 Unset::

 	Unsetting the `crlf` attribute on a path is meant to
 	mark the path as a "binary" file.  The path never goes
 	through line endings conversion upon checkin/checkout.

 Unspecified::

 	Unspecified `crlf` attribute tells git to apply the
 	`core.autocrlf` conversion when the file content looks
 	like text.

 Set to string value "input"::

 	This is similar to setting the attribute to `true`, but
 	also forces git to act as if `core.autocrlf` is set to
 	`input` for the path.

 Any other value set to `crlf` attribute is ignored and git acts
 as if the attribute is left unspecified.


 The `core.autocrlf` conversion
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

 If the configuration variable `core.autocrlf` is false, no
 conversion is done.

 When `core.autocrlf` is true, it means that the platform wants
 CRLF line endings for files in the working tree, and you want to
 convert them back to the normal LF line endings when checking
 in to the repository.

 When `core.autocrlf` is set to "input", line endings are
 converted to LF upon checkin, but there is no conversion done
 upon checkout.


 Generating diff text
 ~~~~~~~~~~~~~~~~~~~~

 The attribute `diff` affects if `git diff` generates textual
 patch for the path or just says `Binary files differ`.

 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`.

 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`.

 Any other value set to `diff` attribute is ignored and git acts
 as if the attribute is left unspecified.


 Performing a three-way merge
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 The attribute `merge` affects how three versions of a file is
 merged when a file-level merge is necessary during `git merge`,
 and other programs 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 does
 	not have a well-defined merge semantics.

 Unspecified::

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

 Any other string value::

 	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 by "binary".


 Defining a custom merge driver
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

 The definition of a merge 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 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.

 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.


 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
    diretory 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/gitattributes`.  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 assignement to `t/abc` becomes:

 ----------------------------------------------------------------
 foo	set to true
 bar	unspecified
 baz	set to false
 merge	set to string value "filfre"
 frotz	unspecified
 ----------------------------------------------------------------


 GIT
 ---
 Part of the gitlink:git[7] suite
	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:

	glob attr1 attr2 ...

	That is, a glob pattern followed by an attributes list,
	separated by whitespaces. When the glob 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 glob pattern matches the path, and nothing says if
	the path has or does not have the attribute.

	When more than one glob pattern matches the path, a later line
	overrides an earlier line.

	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 (the further the
	directory that contains `.gitattributes` is from the path in
	question, the lower its precedence).

	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, three operations
	are attributes-aware.

	Checking-out and checking-in
	~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	The attribute `crlf` affects how the contents stored in the
	repository are copied to the working tree files when commands
	such as `git checkout` and `git merge` run. It also affects how
	git stores the contents you prepare in the working tree in the
	repository upon `git add` and `git commit`.

	Set::

	Setting the `crlf` attribute on a path is meant to mark
	the path as a "text" file. 'core.autocrlf' conversion
	takes place without guessing the content type by
	inspection.

	Unset::

	Unsetting the `crlf` attribute on a path is meant to
	mark the path as a "binary" file. The path never goes
	through line endings conversion upon checkin/checkout.

	Unspecified::

	Unspecified `crlf` attribute tells git to apply the
	`core.autocrlf` conversion when the file content looks
	like text.

	Set to string value "input"::

	This is similar to setting the attribute to `true`, but
	also forces git to act as if `core.autocrlf` is set to
	`input` for the path.

	Any other value set to `crlf` attribute is ignored and git acts
	as if the attribute is left unspecified.


	The `core.autocrlf` conversion
	^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

	If the configuration variable `core.autocrlf` is false, no
	conversion is done.

	When `core.autocrlf` is true, it means that the platform wants
	CRLF line endings for files in the working tree, and you want to
	convert them back to the normal LF line endings when checking
	in to the repository.

	When `core.autocrlf` is set to "input", line endings are
	converted to LF upon checkin, but there is no conversion done
	upon checkout.


	Generating diff text
	~~~~~~~~~~~~~~~~~~~~

	The attribute `diff` affects if `git diff` generates textual
	patch for the path or just says `Binary files differ`.

	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`.

	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`.

	Any other value set to `diff` attribute is ignored and git acts
	as if the attribute is left unspecified.


	Performing a three-way merge
	~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	The attribute `merge` affects how three versions of a file is
	merged when a file-level merge is necessary during `git merge`,
	and other programs 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 does
	not have a well-defined merge semantics.

	Unspecified::

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

	Any other string value::

	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 by "binary".


	Defining a custom merge driver
	^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

	The definition of a merge 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 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.

	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.


	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
	diretory 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/gitattributes`. 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 assignement to `t/abc` becomes:

	----------------------------------------------------------------
	foo set to true
	bar unspecified
	baz set to false
	merge set to string value "filfre"
	frotz unspecified
	----------------------------------------------------------------


	GIT
	---
	Part of the gitlink:git[7] suite