The old text made it sound like macros are only allowed in the .gitattributes file at the top-level of the working tree. Make it clear that they are also allowed in $GIT_DIR/info/attributes and in the global and system-wide gitattributes files. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
		
			
				
	
	
		
			1001 lines
		
	
	
		
			34 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
			
		
		
	
	
			1001 lines
		
	
	
		
			34 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
gitattributes(5)
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================
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NAME
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----
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gitattributes - defining attributes per path
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SYNOPSIS
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--------
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$GIT_DIR/info/attributes, .gitattributes
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DESCRIPTION
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-----------
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A `gitattributes` file is a simple text file that gives
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`attributes` to pathnames.
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Each line in `gitattributes` file is of form:
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	pattern	attr1 attr2 ...
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That is, a pattern followed by an attributes list,
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separated by whitespaces.  When the pattern matches the
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path in question, the attributes listed on the line are given to
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the path.
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Each attribute can be in one of these states for a given path:
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Set::
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	The path has the attribute with special value "true";
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	this is specified by listing only the name of the
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	attribute in the attribute list.
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Unset::
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	The path has the attribute with special value "false";
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	this is specified by listing the name of the attribute
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	prefixed with a dash `-` in the attribute list.
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Set to a value::
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	The path has the attribute with specified string value;
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	this is specified by listing the name of the attribute
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	followed by an equal sign `=` and its value in the
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	attribute list.
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Unspecified::
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	No pattern matches the path, and nothing says if
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	the path has or does not have the attribute, the
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	attribute for the path is said to be Unspecified.
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When more than one pattern matches the path, a later line
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overrides an earlier line.  This overriding is done per
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attribute.  The rules how the pattern matches paths are the
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same as in `.gitignore` files; see linkgit:gitignore[5].
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Unlike `.gitignore`, negative patterns are forbidden.
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When deciding what attributes are assigned to a path, Git
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consults `$GIT_DIR/info/attributes` file (which has the highest
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precedence), `.gitattributes` file in the same directory as the
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path in question, and its parent directories up to the toplevel of the
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work tree (the further the directory that contains `.gitattributes`
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is from the path in question, the lower its precedence). Finally
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global and system-wide files are considered (they have the lowest
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precedence).
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When the `.gitattributes` file is missing from the work tree, the
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path in the index is used as a fall-back.  During checkout process,
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`.gitattributes` in the index is used and then the file in the
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working tree is used as a fall-back.
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If you wish to affect only a single repository (i.e., to assign
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attributes to files that are particular to
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one user's workflow for that repository), then
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attributes should be placed in the `$GIT_DIR/info/attributes` file.
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Attributes which should be version-controlled and distributed to other
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repositories (i.e., attributes of interest to all users) should go into
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`.gitattributes` files. Attributes that should affect all repositories
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for a single user should be placed in a file specified by the
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`core.attributesfile` configuration option (see linkgit:git-config[1]).
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Its default value is $XDG_CONFIG_HOME/git/attributes. If $XDG_CONFIG_HOME
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is either not set or empty, $HOME/.config/git/attributes is used instead.
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Attributes for all users on a system should be placed in the
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`$(prefix)/etc/gitattributes` file.
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Sometimes you would need to override an setting of an attribute
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for a path to `Unspecified` state.  This can be done by listing
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the name of the attribute prefixed with an exclamation point `!`.
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EFFECTS
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-------
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Certain operations by Git can be influenced by assigning
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particular attributes to a path.  Currently, the following
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operations are attributes-aware.
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Checking-out and checking-in
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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These attributes affect how the contents stored in the
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repository are copied to the working tree files when commands
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such as 'git checkout' and 'git merge' run.  They also affect how
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Git stores the contents you prepare in the working tree in the
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repository upon 'git add' and 'git commit'.
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`text`
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^^^^^^
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This attribute enables and controls end-of-line normalization.  When a
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text file is normalized, its line endings are converted to LF in the
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repository.  To control what line ending style is used in the working
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directory, use the `eol` attribute for a single file and the
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`core.eol` configuration variable for all text files.
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Set::
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	Setting the `text` attribute on a path enables end-of-line
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	normalization and marks the path as a text file.  End-of-line
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	conversion takes place without guessing the content type.
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Unset::
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	Unsetting the `text` attribute on a path tells Git not to
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	attempt any end-of-line conversion upon checkin or checkout.
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Set to string value "auto"::
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	When `text` is set to "auto", the path is marked for automatic
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	end-of-line normalization.  If Git decides that the content is
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	text, its line endings are normalized to LF on checkin.
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Unspecified::
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	If the `text` attribute is unspecified, Git uses the
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	`core.autocrlf` configuration variable to determine if the
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	file should be converted.
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Any other value causes Git to act as if `text` has been left
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unspecified.
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`eol`
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^^^^^
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This attribute sets a specific line-ending style to be used in the
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working directory.  It enables end-of-line normalization without any
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content checks, effectively setting the `text` attribute.
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Set to string value "crlf"::
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	This setting forces Git to normalize line endings for this
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	file on checkin and convert them to CRLF when the file is
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	checked out.
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Set to string value "lf"::
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	This setting forces Git to normalize line endings to LF on
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	checkin and prevents conversion to CRLF when the file is
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	checked out.
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Backwards compatibility with `crlf` attribute
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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For backwards compatibility, the `crlf` attribute is interpreted as
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follows:
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------------------------
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crlf		text
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-crlf		-text
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crlf=input	eol=lf
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------------------------
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End-of-line conversion
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^^^^^^^^^^^^^^^^^^^^^^
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While Git normally leaves file contents alone, it can be configured to
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normalize line endings to LF in the repository and, optionally, to
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convert them to CRLF when files are checked out.
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Here is an example that will make Git normalize .txt, .vcproj and .sh
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files, ensure that .vcproj files have CRLF and .sh files have LF in
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the working directory, and prevent .jpg files from being normalized
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regardless of their content.
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------------------------
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*.txt		text
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*.vcproj	eol=crlf
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*.sh		eol=lf
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*.jpg		-text
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------------------------
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Other source code management systems normalize all text files in their
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repositories, and there are two ways to enable similar automatic
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normalization in Git.
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If you simply want to have CRLF line endings in your working directory
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regardless of the repository you are working with, you can set the
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config variable "core.autocrlf" without changing any attributes.
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------------------------
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[core]
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	autocrlf = true
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------------------------
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This does not force normalization of all text files, but does ensure
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that text files that you introduce to the repository have their line
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endings normalized to LF when they are added, and that files that are
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already normalized in the repository stay normalized.
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If you want to interoperate with a source code management system that
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enforces end-of-line normalization, or you simply want all text files
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in your repository to be normalized, you should instead set the `text`
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attribute to "auto" for _all_ files.
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------------------------
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*	text=auto
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------------------------
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This ensures that all files that Git considers to be text will have
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normalized (LF) line endings in the repository.  The `core.eol`
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configuration variable controls which line endings Git will use for
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normalized files in your working directory; the default is to use the
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native line ending for your platform, or CRLF if `core.autocrlf` is
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set.
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NOTE: When `text=auto` normalization is enabled in an existing
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repository, any text files containing CRLFs should be normalized.  If
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they are not they will be normalized the next time someone tries to
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change them, causing unfortunate misattribution.  From a clean working
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directory:
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-------------------------------------------------
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$ echo "* text=auto" >>.gitattributes
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$ rm .git/index     # Remove the index to force Git to
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$ git reset         # re-scan the working directory
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$ git status        # Show files that will be normalized
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$ git add -u
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$ git add .gitattributes
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$ git commit -m "Introduce end-of-line normalization"
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-------------------------------------------------
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If any files that should not be normalized show up in 'git status',
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unset their `text` attribute before running 'git add -u'.
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------------------------
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manual.pdf	-text
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------------------------
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Conversely, text files that Git does not detect can have normalization
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enabled manually.
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------------------------
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weirdchars.txt	text
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------------------------
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If `core.safecrlf` is set to "true" or "warn", Git verifies if
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the conversion is reversible for the current setting of
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`core.autocrlf`.  For "true", Git rejects irreversible
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conversions; for "warn", Git only prints a warning but accepts
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an irreversible conversion.  The safety triggers to prevent such
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a conversion done to the files in the work tree, but there are a
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few exceptions.  Even though...
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- 'git add' itself does not touch the files in the work tree, the
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  next checkout would, so the safety triggers;
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- 'git apply' to update a text file with a patch does touch the files
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  in the work tree, but the operation is about text files and CRLF
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  conversion is about fixing the line ending inconsistencies, so the
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  safety does not trigger;
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- 'git diff' itself does not touch the files in the work tree, it is
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  often run to inspect the changes you intend to next 'git add'.  To
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  catch potential problems early, safety triggers.
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`ident`
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^^^^^^^
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When the attribute `ident` is set for a path, Git replaces
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`$Id$` in the blob object with `$Id:`, followed by the
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40-character hexadecimal blob object name, followed by a dollar
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sign `$` upon checkout.  Any byte sequence that begins with
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`$Id:` and ends with `$` in the worktree file is replaced
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with `$Id$` upon check-in.
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`filter`
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^^^^^^^^
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A `filter` attribute can be set to a string value that names a
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filter driver specified in the configuration.
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A filter driver consists of a `clean` command and a `smudge`
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command, either of which can be left unspecified.  Upon
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checkout, when the `smudge` command is specified, the command is
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fed the blob object from its standard input, and its standard
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output is used to update the worktree file.  Similarly, the
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`clean` command is used to convert the contents of worktree file
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upon checkin.
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One use of the content filtering is to massage the content into a shape
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that is more convenient for the platform, filesystem, and the user to use.
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For this mode of operation, the key phrase here is "more convenient" and
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not "turning something unusable into usable".  In other words, the intent
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is that if someone unsets the filter driver definition, or does not have
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the appropriate filter program, the project should still be usable.
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Another use of the content filtering is to store the content that cannot
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be directly used in the repository (e.g. a UUID that refers to the true
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content stored outside Git, or an encrypted content) and turn it into a
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usable form upon checkout (e.g. download the external content, or decrypt
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the encrypted content).
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These two filters behave differently, and by default, a filter is taken as
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the former, massaging the contents into more convenient shape.  A missing
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filter driver definition in the config, or a filter driver that exits with
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a non-zero status, is not an error but makes the filter a no-op passthru.
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You can declare that a filter turns a content that by itself is unusable
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into a usable content by setting the filter.<driver>.required configuration
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variable to `true`.
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For example, in .gitattributes, you would assign the `filter`
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attribute for paths.
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------------------------
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*.c	filter=indent
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------------------------
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Then you would define a "filter.indent.clean" and "filter.indent.smudge"
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configuration in your .git/config to specify a pair of commands to
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modify the contents of C programs when the source files are checked
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in ("clean" is run) and checked out (no change is made because the
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command is "cat").
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------------------------
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[filter "indent"]
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	clean = indent
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	smudge = cat
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------------------------
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For best results, `clean` should not alter its output further if it is
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run twice ("clean->clean" should be equivalent to "clean"), and
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multiple `smudge` commands should not alter `clean`'s output
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("smudge->smudge->clean" should be equivalent to "clean").  See the
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section on merging below.
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The "indent" filter is well-behaved in this regard: it will not modify
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input that is already correctly indented.  In this case, the lack of a
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smudge filter means that the clean filter _must_ accept its own output
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without modifying it.
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If a filter _must_ succeed in order to make the stored contents usable,
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you can declare that the filter is `required`, in the configuration:
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------------------------
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[filter "crypt"]
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	clean = openssl enc ...
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	smudge = openssl enc -d ...
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	required
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------------------------
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Sequence "%f" on the filter command line is replaced with the name of
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the file the filter is working on.  A filter might use this in keyword
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substitution.  For example:
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------------------------
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[filter "p4"]
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	clean = git-p4-filter --clean %f
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	smudge = git-p4-filter --smudge %f
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------------------------
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Interaction between checkin/checkout attributes
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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In the check-in codepath, the worktree file is first converted
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with `filter` driver (if specified and corresponding driver
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defined), then the result is processed with `ident` (if
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specified), and then finally with `text` (again, if specified
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and applicable).
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In the check-out codepath, the blob content is first converted
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with `text`, and then `ident` and fed to `filter`.
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Merging branches with differing checkin/checkout attributes
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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If you have added attributes to a file that cause the canonical
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repository format for that file to change, such as adding a
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clean/smudge filter or text/eol/ident attributes, merging anything
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where the attribute is not in place would normally cause merge
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conflicts.
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To prevent these unnecessary merge conflicts, Git can be told to run a
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virtual check-out and check-in of all three stages of a file when
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resolving a three-way merge by setting the `merge.renormalize`
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configuration variable.  This prevents changes caused by check-in
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conversion from causing spurious merge conflicts when a converted file
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is merged with an unconverted file.
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As long as a "smudge->clean" results in the same output as a "clean"
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even on files that are already smudged, this strategy will
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automatically resolve all filter-related conflicts.  Filters that do
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not act in this way may cause additional merge conflicts that must be
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resolved manually.
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Generating diff text
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~~~~~~~~~~~~~~~~~~~~
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`diff`
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^^^^^^
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The attribute `diff` affects how Git generates diffs for particular
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files. It can tell Git whether to generate a textual patch for the path
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or to treat the path as a binary file.  It can also affect what line is
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shown on the hunk header `@@ -k,l +n,m @@` line, tell Git to use an
 | 
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external command to generate the diff, or ask Git to convert binary
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files to a text format before generating the diff.
 | 
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Set::
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	A path to which the `diff` attribute is set is treated
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	as text, even when they contain byte values that
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	normally never appear in text files, such as NUL.
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Unset::
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	A path to which the `diff` attribute is unset will
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	generate `Binary files differ` (or a binary patch, if
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	binary patches are enabled).
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Unspecified::
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	A path to which the `diff` attribute is unspecified
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	first gets its contents inspected, and if it looks like
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	text, it is treated as text.  Otherwise it would
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	generate `Binary files differ`.
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String::
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	Diff is shown using the specified diff driver.  Each driver may
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	specify one or more options, as described in the following
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	section. The options for the diff driver "foo" are defined
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	by the configuration variables in the "diff.foo" section of the
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	Git config file.
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Defining an external diff driver
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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The definition of a diff driver is done in `gitconfig`, not
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`gitattributes` file, so strictly speaking this manual page is a
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wrong place to talk about it.  However...
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 | 
						|
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 linkgit: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 linkgit: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
 | 
						|
linkgit: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 linkgit: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. linkgit:gitk[1] and linkgit:git-gui[1]) to
 | 
						|
display the contents of the relevant file. Note that due to performance
 | 
						|
considerations linkgit: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 linkgit: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
 | 
						|
--------
 | 
						|
linkgit:git-check-attr[1].
 | 
						|
 | 
						|
GIT
 | 
						|
---
 | 
						|
Part of the linkgit:git[1] suite
 |