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.TH "GIT-DIFF-TREE" 1 "" "" ""
.SH NAME
git-diff-tree \- Compares the content and mode of blobs found via two tree objects
.SH "SYNOPSIS"

.nf
git\-diff\-tree [\-\-stdin] [\-m] [\-s] [\-v] [\-\-no\-commit\-id] [\-\-pretty]
              [\-t] [\-r] [\-c | \-\-cc] [\-\-root] [<common diff options>]
              <tree\-ish> [<tree\-ish>] [<path>...]
.fi

.SH "DESCRIPTION"


Compares the content and mode of the blobs found via two tree objects\&.


If there is only one <tree\-ish> given, the commit is compared with its parents (see \-\-stdin below)\&.


Note that "git\-diff\-tree" can use the tree encapsulated in a commit object\&.

.SH "OPTIONS"

.TP
\-p
Generate patch (see section on generating patches)

.TP
\-u
Synonym for "\-p"\&.

.TP
\-z
\\0 line termination on output

.TP
\-\-name\-only
Show only names of changed files\&.

.TP
\-\-name\-status
Show only names and status of changed files\&.

.TP
\-\-full\-index
Instead of the first handful characters, show full object name of pre\- and post\-image blob on the "index" line when generating a patch format output\&.

.TP
\-\-abbrev[=<n>]
Instead of showing the full 40\-byte hexadecimal object name in diff\-raw format output and diff\-tree header lines, show only handful hexdigits prefix\&. This is independent of \-\-full\-index option above, which controls the diff\-patch output format\&. Non default number of digits can be specified with \-\-abbrev=<n>\&.

.TP
\-B
Break complete rewrite changes into pairs of delete and create\&.

.TP
\-M
Detect renames\&.

.TP
\-C
Detect copies as well as renames\&.

.TP
\-\-find\-copies\-harder
For performance reasons, by default, \-C option finds copies only if the original file of the copy was modified in the same changeset\&. This flag makes the command inspect unmodified files as candidates for the source of copy\&. This is a very expensive operation for large projects, so use it with caution\&.

.TP
\-l<num>
\-M and \-C options require O(n^2) processing time where n is the number of potential rename/copy targets\&. This option prevents rename/copy detection from running if the number of rename/copy targets exceeds the specified number\&.

.TP
\-S<string>
Look for differences that contain the change in <string>\&.

.TP
\-\-pickaxe\-all
When \-S finds a change, show all the changes in that changeset, not just the files that contain the change in <string>\&.

.TP
\-O<orderfile>
Output the patch in the order specified in the <orderfile>, which has one shell glob pattern per line\&.

.TP
\-R
Swap two inputs; that is, show differences from index or on\-disk file to tree contents\&.


For more detailed explanation on these common options, see also diffcore documentation: \fIdiffcore.html\fR\&.

.TP
<tree\-ish>
The id of a tree object\&.

.TP
<path>...
If provided, the results are limited to a subset of files matching one of these prefix strings\&. ie file matches /^<pattern1>|<pattern2>|.../ Note that this parameter does not provide any wildcard or regexp features\&.

.TP
\-r
recurse into sub\-trees

.TP
\-t
show tree entry itself as well as subtrees\&. Implies \-r\&.

.TP
\-\-root
When \-\-root is specified the initial commit will be showed as a big creation event\&. This is equivalent to a diff against the NULL tree\&.

.TP
\-\-stdin
When \-\-stdin is specified, the command does not take <tree\-ish> arguments from the command line\&. Instead, it reads either one <commit> or a pair of <tree\-ish> separated with a single space from its standard input\&.

When a single commit is given on one line of such input, it compares the commit with its parents\&. The following flags further affects its behaviour\&. This does not apply to the case where two <tree\-ish> separated with a single space are given\&.

.TP
\-m
By default, "git\-diff\-tree \-\-stdin" does not show differences for merge commits\&. With this flag, it shows differences to that commit from all of its parents\&.

.TP
\-s
By default, "git\-diff\-tree \-\-stdin" shows differences, either in machine\-readable form (without \-p) or in patch form (with \-p)\&. This output can be suppressed\&. It is only useful with \-v flag\&.

.TP
\-v
This flag causes "git\-diff\-tree \-\-stdin" to also show the commit message before the differences\&.

.TP
\-\-pretty[=(raw|medium|short)]
This is used to control "pretty printing" format of the commit message\&. Without "=<style>", it defaults to medium\&.

.TP
\-\-no\-commit\-id
git\-diff\-tree outputs a line with the commit ID when applicable\&. This flag suppressed the commit ID output\&.

.TP
\-c,\-\-cc
These flags change the way a merge commit is displayed (which means it is useful only when the command is given one <tree\-ish>, or \-\-stdin)\&. It shows the differences from each of the parents to the merge result simultaneously, instead of showing pairwise diff between a parent and the result one at a time, which \-m option output does\&. \-\-cc further compresses the output by omiting hunks that show differences from only one parent, or show the same change from all but one parent for an Octopus merge\&. When this optimization makes all hunks disappear, the commit itself and the commit log message is not shown, unless \-m is specified\&.

.SH "LIMITING OUTPUT"


If you're only interested in differences in a subset of files, for example some architecture\-specific files, you might do:

.nf
git\-diff\-tree \-r <tree\-ish> <tree\-ish> arch/ia64 include/asm\-ia64
.fi


and it will only show you what changed in those two directories\&.


Or if you are searching for what changed in just kernel/sched\&.c, just do

.nf
git\-diff\-tree \-r <tree\-ish> <tree\-ish> kernel/sched\&.c
.fi


and it will ignore all differences to other files\&.


The pattern is always the prefix, and is matched exactly\&. There are no wildcards\&. Even stricter, it has to match a complete path component\&. I\&.e\&. "foo" does not pick up foobar\&.h\&. "foo" does match foo/bar\&.h so it can be used to name subdirectories\&.


An example of normal usage is:

.nf
torvalds@ppc970:~/git> git\-diff\-tree 5319e4\&.\&.\&.\&.\&.\&.
*100664\->100664 blob    ac348b\&.\&.\&.\&.\&.\&.\&.\->a01513\&.\&.\&.\&.\&.\&.\&.      git\-fsck\-objects\&.c
.fi


which tells you that the last commit changed just one file (it's from this one:

.IP
commit 3c6f7ca19ad4043e9e72fa94106f352897e651a8
tree 5319e4d609cdd282069cc4dce33c1db559539b03
parent b4e628ea30d5ab3606119d2ea5caeab141d38df7
author Linus Torvalds <torvalds@ppc970\&.osdl\&.org> Sat Apr 9 12:02:30 2005
committer Linus Torvalds <torvalds@ppc970\&.osdl\&.org> Sat Apr 9 12:02:30 2005

Make "git\-fsck\-objects" print out all the root commits it finds\&.

Once I do the reference tracking, I'll also make it print out all the
HEAD commits it finds, which is even more interesting\&.

in case you care)\&.

.SH "OUTPUT FORMAT"


The output format from "git\-diff\-index", "git\-diff\-tree" and "git\-diff\-files" are very similar\&.


These commands all compare two sets of things; what is compared differs:

.TP
git\-diff\-index <tree\-ish>
compares the <tree\-ish> and the files on the filesystem\&.

.TP
git\-diff\-index \-\-cached <tree\-ish>
compares the <tree\-ish> and the index\&.

.TP
git\-diff\-tree [\-r] <tree\-ish\-1> <tree\-ish\-2> [<pattern>...]
compares the trees named by the two arguments\&.

.TP
git\-diff\-files [<pattern>...]
compares the index and the files on the filesystem\&.


An output line is formatted this way:

.IP
in\-place edit  :100644 100644 bcd1234\&.\&.\&. 0123456\&.\&.\&. M file0
copy\-edit      :100644 100644 abcd123\&.\&.\&. 1234567\&.\&.\&. C68 file1 file2
rename\-edit    :100644 100644 abcd123\&.\&.\&. 1234567\&.\&.\&. R86 file1 file3
create         :000000 100644 0000000\&.\&.\&. 1234567\&.\&.\&. A file4
delete         :100644 000000 1234567\&.\&.\&. 0000000\&.\&.\&. D file5
unmerged       :000000 000000 0000000\&.\&.\&. 0000000\&.\&.\&. U file6

That is, from the left to the right:

.TP 3
1.
a colon\&.
.TP
2.
mode for "src"; 000000 if creation or unmerged\&.
.TP
3.
a space\&.
.TP
4.
mode for "dst"; 000000 if deletion or unmerged\&.
.TP
5.
a space\&.
.TP
6.
sha1 for "src"; 0{40} if creation or unmerged\&.
.TP
7.
a space\&.
.TP
8.
sha1 for "dst"; 0{40} if creation, unmerged or "look at work tree"\&.
.TP
9.
a space\&.
.TP
10.
status, followed by optional "score" number\&.
.TP
11.
a tab or a NUL when \-z option is used\&.
.TP
12.
path for "src"
.TP
13.
a tab or a NUL when \-z option is used; only exists for C or R\&.
.TP
14.
path for "dst"; only exists for C or R\&.
.TP
15.
an LF or a NUL when \-z option is used, to terminate the record\&.
.LP


<sha1> is shown as all 0's if a file is new on the filesystem and it is out of sync with the index\&.


Example:

.IP
:100644 100644 5be4a4\&.\&.\&.\&.\&.\&. 000000\&.\&.\&.\&.\&.\&. M file\&.c

When \-z option is not used, TAB, LF, and backslash characters in pathnames are represented as \\t, \\n, and \\\\, respectively\&.

.SH "GENERATING PATCHES WITH -P"


When "git\-diff\-index", "git\-diff\-tree", or "git\-diff\-files" are run with a \-p option, they do not produce the output described above; instead they produce a patch file\&.


The patch generation can be customized at two levels\&.

.TP 3
1.
When the environment variable GIT_EXTERNAL_DIFF is not set, these commands internally invoke "diff" like this:


.nf
diff \-L a/<path> \-L b/<path> \-pu <old> <new>
.fi
For added files, /dev/null is used for <old>\&. For removed files, /dev/null is used for <new>

The "diff" formatting options can be customized via the environment variable GIT_DIFF_OPTS\&. For example, if you prefer context diff:

.nf
GIT_DIFF_OPTS=\-c git\-diff\-index \-p HEAD
.fi
.TP
2.
When the environment variable GIT_EXTERNAL_DIFF is set, the program named by it is called, instead of the diff invocation described above\&.

For a path that is added, removed, or modified, GIT_EXTERNAL_DIFF is called with 7 parameters:


.nf
path old\-file old\-hex old\-mode new\-file new\-hex new\-mode
.fi
where:

<old|new>\-file
are files GIT_EXTERNAL_DIFF can use to read the contents of <old|new>,
<old|new>\-hex
are the 40\-hexdigit SHA1 hashes,
<old|new>\-mode
are the octal representation of the file modes\&.
The file parameters can point at the user's working file (e\&.g\&. new\-file in "git\-diff\-files"), /dev/null (e\&.g\&. old\-file when a new file is added), or a temporary file (e\&.g\&. old\-file in the index)\&. GIT_EXTERNAL_DIFF should not worry about unlinking the temporary file \-\-\- it is removed when GIT_EXTERNAL_DIFF exits\&.
.LP


For a path that is unmerged, GIT_EXTERNAL_DIFF is called with 1 parameter, <path>\&.

.SH "GIT SPECIFIC EXTENSION TO DIFF FORMAT"


What \-p option produces is slightly different from the traditional diff format\&.

.TP 3
1.
It is preceded with a "git diff" header, that looks like this:


.nf
diff \-\-git a/file1 b/file2
.fi
The a/ and b/ filenames are the same unless rename/copy is involved\&. Especially, even for a creation or a deletion, /dev/null is _not_ used in place of a/ or b/ filenames\&.

When rename/copy is involved, file1 and file2 show the name of the source file of the rename/copy and the name of the file that rename/copy produces, respectively\&.
.TP
2.
It is followed by one or more extended header lines:

.nf
old mode <mode>
new mode <mode>
deleted file mode <mode>
new file mode <mode>
copy from <path>
copy to <path>
rename from <path>
rename to <path>
similarity index <number>
dissimilarity index <number>
index <hash>\&.\&.<hash> <mode>
.fi
.TP
3.
TAB, LF, and backslash characters in pathnames are represented as \\t, \\n, and \\\\, respectively\&.
.LP

.SH "COMBINED DIFF FORMAT"


git\-diff\-tree and git\-diff\-files can take \-c or \-\-cc option to produce combined diff, which looks like this:

.IP
diff \-\-combined describe\&.c
@@@ +98,7 @@@
   return (a_date > b_date) ? \-1 : (a_date == b_date) ? 0 : 1;
  }

\- static void describe(char *arg)
 \-static void describe(struct commit *cmit, int last_one)
++static void describe(char *arg, int last_one)
  {
 +     unsigned char sha1[20];
 +     struct commit *cmit;

Unlike the traditional unified diff format, which shows two files A and B with a single column that has \- (minus -- appears in A but removed in B), + (plus -- missing in A but added to B), or (space -- unchanged) prefix, this format compares two or more files file1, file2,... with one file X, and shows how X differs from each of fileN\&. One column for each of fileN is prepended to the output line to note how X's line is different from it\&.


A \- character in the column N means that the line appears in fileN but it does not appear in the last file\&. A + character in the column N means that the line appears in the last file, and fileN does not have that line\&.


In the above example output, the function signature was changed from both files (hence two \- removals from both file1 and file2, plus ++ to mean one line that was added does not appear in either file1 nor file2)\&. Also two other lines are the same from file1 but do not appear in file2 (hence prefixed with +)\&.


When shown by git diff\-tree \-c, it compares the parents of a merge commit with the merge result (i\&.e\&. file1\&.\&.fileN are the parents)\&. When shown by git diff\-files \-c, it compares the two unresolved merge parents with the working tree file (i\&.e\&. file1 is stage 2 aka "our version", file2 is stage 3 aka "their version")\&.

.SH "AUTHOR"


Written by Linus Torvalds <torvalds@osdl\&.org>

.SH "DOCUMENTATION"


Documentation by David Greaves, Junio C Hamano and the git\-list <git@vger\&.kernel\&.org>\&.

.SH "GIT"


Part of the \fBgit\fR(7) suite