$GIT_DIR/info/attributes, .gitattributes
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
Unset
Set to a value
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).
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).
If you wish to affect only a single repository (i.e., to assign attributes to files that are particular to one user's workflow), 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.
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 !.
Certain operations by git can be influenced by assigning particular attributes to a path. Currently, the following operations are attributes-aware.
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.
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
Unset
Set to string value "auto"
Unspecified
Any other value causes git to act as if text has been left unspecified.
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"
Set to string value "lf"
For backwards compatibility, the crlf attribute is interpreted as follows:
text
crlf text -crlf -text crlf=input eol=lf
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.
End-of-line conversion
*.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.
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.
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.
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.
A missing filter driver definition in the config is not an error but makes the filter a no-op passthru.
The content filtering is done to massage the content into a shape that is more convenient for the platform, filesystem, and the user to use. 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.
For example, in .gitattributes, you would assign the filter attribute for paths.
ident
*.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
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.
Interaction between checkin/checkout attributes
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
Unset
Unspecified
String
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
[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.
Each group of changes (called a "hunk") in the textual diff output is prefixed with a line of the form:
Defining a custom hunk-header
@@ -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:
bibtex suitable for files with BibTeX coded references.
cpp suitable for source code in the C and C++ languages.
html suitable for HTML/XHTML documents.
java suitable for source code in the Java language.
objc suitable for source code in the Objective-C language.
pascal suitable for source code in the Pascal/Delphi 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.
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:
Customizing word diff
[diff "tex"]
wordRegex = "\\\\[a-zA-Z]+|[{}]|\\\\.|[^\\{}[:space:]]+"
A built-in pattern is provided for all languages listed in the previous section.
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):
Performing text diffs of binary files
[diff "jpg"]
textconv = exif
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).
The attribute merge affects how three versions of a file is merged when a file-level merge is necessary during git merge, and other commands such as git revert and git cherry-pick.
Set
Unset
Unspecified
String
There are a few built-in low-level merge drivers defined that can be asked for via the merge attribute.
text
binary
union
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
[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.
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.
conflict-marker-size
Documentation/git-merge.txt conflict-marker-size=32
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
Unset
Unspecified
String
whitespace
Files and directories with the attribute export-ignore won't be added to archive files.
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.
export-ignore
Delta compression will not be attempted for blobs for paths with the attribute delta set to false.
delta
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)).
encoding
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 attribute macros, you can specify groups of attributes set or unset at the same time. The system knows a built-in attribute macro, binary:
*.jpg binary
which is equivalent to the above. Note that the attribute macros can only be "Set" (see the above example that sets "binary" macro as if it were an ordinary attribute --- setting it in turn unsets "text" and "diff").
Custom attribute macros can be defined only in the .gitattributes file at the toplevel (i.e. not in any subdirectory). The built-in attribute macro "binary" is equivalent to:
[attr]binary -diff -text
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:
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
Part of the git(1) suite