Provided by: git-man_2.45.2-1.2ubuntu1_all 
NAME
git-diff-index - Compare a tree to the working tree or index
SYNOPSIS
git diff-index [-m] [--cached] [--merge-base] [<common-diff-options>] <tree-ish> [<path>...]
DESCRIPTION
Compare the content and mode of the blobs found in a tree object with the corresponding
tracked files in the working tree, or with the corresponding paths in the index. When
<path> arguments are present, compare only paths matching those patterns. Otherwise all
tracked files are compared.
OPTIONS
-p, -u, --patch
Generate patch (see the section called “GENERATING PATCH TEXT WITH -P”).
-s, --no-patch
Suppress all output from the diff machinery. Useful for commands like git show that
show the patch by default to squelch their output, or to cancel the effect of options
like --patch, --stat earlier on the command line in an alias.
-U<n>, --unified=<n>
Generate diffs with <n> lines of context instead of the usual three. Implies --patch.
--output=<file>
Output to a specific file instead of stdout.
--output-indicator-new=<char>, --output-indicator-old=<char>,
--output-indicator-context=<char>
Specify the character used to indicate new, old or context lines in the generated
patch. Normally they are +, - and ' ' respectively.
--raw
Generate the diff in raw format. This is the default.
--patch-with-raw
Synonym for -p --raw.
--indent-heuristic
Enable the heuristic that shifts diff hunk boundaries to make patches easier to read.
This is the default.
--no-indent-heuristic
Disable the indent heuristic.
--minimal
Spend extra time to make sure the smallest possible diff is produced.
--patience
Generate a diff using the "patience diff" algorithm.
--histogram
Generate a diff using the "histogram diff" algorithm.
--anchored=<text>
Generate a diff using the "anchored diff" algorithm.
This option may be specified more than once.
If a line exists in both the source and destination, exists only once, and starts with
this text, this algorithm attempts to prevent it from appearing as a deletion or
addition in the output. It uses the "patience diff" algorithm internally.
--diff-algorithm={patience|minimal|histogram|myers}
Choose a diff algorithm. The variants are as follows:
default, myers
The basic greedy diff algorithm. Currently, this is the default.
minimal
Spend extra time to make sure the smallest possible diff is produced.
patience
Use "patience diff" algorithm when generating patches.
histogram
This algorithm extends the patience algorithm to "support low-occurrence common
elements".
For instance, if you configured the diff.algorithm variable to a non-default value and
want to use the default one, then you have to use --diff-algorithm=default option.
--stat[=<width>[,<name-width>[,<count>]]]
Generate a diffstat. By default, as much space as necessary will be used for the
filename part, and the rest for the graph part. Maximum width defaults to terminal
width, or 80 columns if not connected to a terminal, and can be overridden by <width>.
The width of the filename part can be limited by giving another width <name-width>
after a comma or by setting diff.statNameWidth=<width>. The width of the graph part
can be limited by using --stat-graph-width=<width> or by setting
diff.statGraphWidth=<width>. Using --stat or --stat-graph-width affects all commands
generating a stat graph, while setting diff.statNameWidth or diff.statGraphWidth does
not affect git format-patch. By giving a third parameter <count>, you can limit the
output to the first <count> lines, followed by ... if there are more.
These parameters can also be set individually with --stat-width=<width>,
--stat-name-width=<name-width> and --stat-count=<count>.
--compact-summary
Output a condensed summary of extended header information such as file creations or
deletions ("new" or "gone", optionally "+l" if it’s a symlink) and mode changes ("+x"
or "-x" for adding or removing executable bit respectively) in diffstat. The
information is put between the filename part and the graph part. Implies --stat.
--numstat
Similar to --stat, but shows number of added and deleted lines in decimal notation and
pathname without abbreviation, to make it more machine friendly. For binary files,
outputs two - instead of saying 0 0.
--shortstat
Output only the last line of the --stat format containing total number of modified
files, as well as number of added and deleted lines.
-X[<param1,param2,...>], --dirstat[=<param1,param2,...>]
Output the distribution of relative amount of changes for each sub-directory. The
behavior of --dirstat can be customized by passing it a comma separated list of
parameters. The defaults are controlled by the diff.dirstat configuration variable
(see git-config(1)). The following parameters are available:
changes
Compute the dirstat numbers by counting the lines that have been removed from the
source, or added to the destination. This ignores the amount of pure code
movements within a file. In other words, rearranging lines in a file is not
counted as much as other changes. This is the default behavior when no parameter
is given.
lines
Compute the dirstat numbers by doing the regular line-based diff analysis, and
summing the removed/added line counts. (For binary files, count 64-byte chunks
instead, since binary files have no natural concept of lines). This is a more
expensive --dirstat behavior than the changes behavior, but it does count
rearranged lines within a file as much as other changes. The resulting output is
consistent with what you get from the other --*stat options.
files
Compute the dirstat numbers by counting the number of files changed. Each changed
file counts equally in the dirstat analysis. This is the computationally cheapest
--dirstat behavior, since it does not have to look at the file contents at all.
cumulative
Count changes in a child directory for the parent directory as well. Note that
when using cumulative, the sum of the percentages reported may exceed 100%. The
default (non-cumulative) behavior can be specified with the noncumulative
parameter.
<limit>
An integer parameter specifies a cut-off percent (3% by default). Directories
contributing less than this percentage of the changes are not shown in the output.
Example: The following will count changed files, while ignoring directories with less
than 10% of the total amount of changed files, and accumulating child directory counts
in the parent directories: --dirstat=files,10,cumulative.
--cumulative
Synonym for --dirstat=cumulative
--dirstat-by-file[=<param1,param2>...]
Synonym for --dirstat=files,<param1>,<param2>...
--summary
Output a condensed summary of extended header information such as creations, renames
and mode changes.
--patch-with-stat
Synonym for -p --stat.
-z
When --raw, --numstat, --name-only or --name-status has been given, do not munge
pathnames and use NULs as output field terminators.
Without this option, pathnames with "unusual" characters are quoted as explained for
the configuration variable core.quotePath (see git-config(1)).
--name-only
Show only names of changed files. The file names are often encoded in UTF-8. For more
information see the discussion about encoding in the git-log(1) manual page.
--name-status
Show only names and status of changed files. See the description of the --diff-filter
option on what the status letters mean. Just like --name-only the file names are often
encoded in UTF-8.
--submodule[=<format>]
Specify how differences in submodules are shown. When specifying --submodule=short the
short format is used. This format just shows the names of the commits at the beginning
and end of the range. When --submodule or --submodule=log is specified, the log format
is used. This format lists the commits in the range like git-submodule(1) summary
does. When --submodule=diff is specified, the diff format is used. This format shows
an inline diff of the changes in the submodule contents between the commit range.
Defaults to diff.submodule or the short format if the config option is unset.
--color[=<when>]
Show colored diff. --color (i.e. without =<when>) is the same as --color=always.
<when> can be one of always, never, or auto.
--no-color
Turn off colored diff. It is the same as --color=never.
--color-moved[=<mode>]
Moved lines of code are colored differently. The <mode> defaults to no if the option
is not given and to zebra if the option with no mode is given. The mode must be one
of:
no
Moved lines are not highlighted.
default
Is a synonym for zebra. This may change to a more sensible mode in the future.
plain
Any line that is added in one location and was removed in another location will be
colored with color.diff.newMoved. Similarly color.diff.oldMoved will be used for
removed lines that are added somewhere else in the diff. This mode picks up any
moved line, but it is not very useful in a review to determine if a block of code
was moved without permutation.
blocks
Blocks of moved text of at least 20 alphanumeric characters are detected greedily.
The detected blocks are painted using either the color.diff.{old,new}Moved color.
Adjacent blocks cannot be told apart.
zebra
Blocks of moved text are detected as in blocks mode. The blocks are painted using
either the color.diff.{old,new}Moved color or
color.diff.{old,new}MovedAlternative. The change between the two colors indicates
that a new block was detected.
dimmed-zebra
Similar to zebra, but additional dimming of uninteresting parts of moved code is
performed. The bordering lines of two adjacent blocks are considered interesting,
the rest is uninteresting. dimmed_zebra is a deprecated synonym.
--no-color-moved
Turn off move detection. This can be used to override configuration settings. It is
the same as --color-moved=no.
--color-moved-ws=<modes>
This configures how whitespace is ignored when performing the move detection for
--color-moved. These modes can be given as a comma separated list:
no
Do not ignore whitespace when performing move detection.
ignore-space-at-eol
Ignore changes in whitespace at EOL.
ignore-space-change
Ignore changes in amount of whitespace. This ignores whitespace at line end, and
considers all other sequences of one or more whitespace characters to be
equivalent.
ignore-all-space
Ignore whitespace when comparing lines. This ignores differences even if one line
has whitespace where the other line has none.
allow-indentation-change
Initially ignore any whitespace in the move detection, then group the moved code
blocks only into a block if the change in whitespace is the same per line. This is
incompatible with the other modes.
--no-color-moved-ws
Do not ignore whitespace when performing move detection. This can be used to override
configuration settings. It is the same as --color-moved-ws=no.
--word-diff[=<mode>]
Show a word diff, using the <mode> to delimit changed words. By default, words are
delimited by whitespace; see --word-diff-regex below. The <mode> defaults to plain,
and must be one of:
color
Highlight changed words using only colors. Implies --color.
plain
Show words as [-removed-] and {+added+}. Makes no attempts to escape the
delimiters if they appear in the input, so the output may be ambiguous.
porcelain
Use a special line-based format intended for script consumption.
Added/removed/unchanged runs are printed in the usual unified diff format,
starting with a +/-/` ` character at the beginning of the line and extending to
the end of the line. Newlines in the input are represented by a tilde ~ on a line
of its own.
none
Disable word diff again.
Note that despite the name of the first mode, color is used to highlight the changed
parts in all modes if enabled.
--word-diff-regex=<regex>
Use <regex> to decide what a word is, instead of considering runs of non-whitespace to
be a word. Also implies --word-diff unless it was already enabled.
Every non-overlapping match of the <regex> is considered a word. Anything between
these matches is considered whitespace and ignored(!) for the purposes of finding
differences. You may want to append |[^[:space:]] to your regular expression to make
sure that it matches all non-whitespace characters. A match that contains a newline is
silently truncated(!) at the newline.
For example, --word-diff-regex=. will treat each character as a word and,
correspondingly, show differences character by character.
The regex can also be set via a diff driver or configuration option, see
gitattributes(5) or git-config(1). Giving it explicitly overrides any diff driver or
configuration setting. Diff drivers override configuration settings.
--color-words[=<regex>]
Equivalent to --word-diff=color plus (if a regex was specified)
--word-diff-regex=<regex>.
--no-renames
Turn off rename detection, even when the configuration file gives the default to do
so.
--[no-]rename-empty
Whether to use empty blobs as rename source.
--check
Warn if changes introduce conflict markers or whitespace errors. What are considered
whitespace errors is controlled by core.whitespace configuration. By default, trailing
whitespaces (including lines that consist solely of whitespaces) and a space character
that is immediately followed by a tab character inside the initial indent of the line
are considered whitespace errors. Exits with non-zero status if problems are found.
Not compatible with --exit-code.
--ws-error-highlight=<kind>
Highlight whitespace errors in the context, old or new lines of the diff. Multiple
values are separated by comma, none resets previous values, default reset the list to
new and all is a shorthand for old,new,context. When this option is not given, and the
configuration variable diff.wsErrorHighlight is not set, only whitespace errors in new
lines are highlighted. The whitespace errors are colored with color.diff.whitespace.
--full-index
Instead of the first handful of characters, show the full pre- and post-image blob
object names on the "index" line when generating patch format output.
--binary
In addition to --full-index, output a binary diff that can be applied with git-apply.
Implies --patch.
--abbrev[=<n>]
Instead of showing the full 40-byte hexadecimal object name in diff-raw format output
and diff-tree header lines, show the shortest prefix that is at least <n> hexdigits
long that uniquely refers the object. In diff-patch output format, --full-index takes
higher precedence, i.e. if --full-index is specified, full blob names will be shown
regardless of --abbrev. Non default number of digits can be specified with
--abbrev=<n>.
-B[<n>][/<m>], --break-rewrites[=[<n>][/<m>]]
Break complete rewrite changes into pairs of delete and create. This serves two
purposes:
It affects the way a change that amounts to a total rewrite of a file not as a series
of deletion and insertion mixed together with a very few lines that happen to match
textually as the context, but as a single deletion of everything old followed by a
single insertion of everything new, and the number m controls this aspect of the -B
option (defaults to 60%). -B/70% specifies that less than 30% of the original should
remain in the result for Git to consider it a total rewrite (i.e. otherwise the
resulting patch will be a series of deletion and insertion mixed together with context
lines).
When used with -M, a totally-rewritten file is also considered as the source of a
rename (usually -M only considers a file that disappeared as the source of a rename),
and the number n controls this aspect of the -B option (defaults to 50%). -B20%
specifies that a change with addition and deletion compared to 20% or more of the
file’s size are eligible for being picked up as a possible source of a rename to
another file.
-M[<n>], --find-renames[=<n>]
Detect renames. If n is specified, it is a threshold on the similarity index (i.e.
amount of addition/deletions compared to the file’s size). For example, -M90% means
Git should consider a delete/add pair to be a rename if more than 90% of the file
hasn’t changed. Without a % sign, the number is to be read as a fraction, with a
decimal point before it. I.e., -M5 becomes 0.5, and is thus the same as -M50%.
Similarly, -M05 is the same as -M5%. To limit detection to exact renames, use -M100%.
The default similarity index is 50%.
-C[<n>], --find-copies[=<n>]
Detect copies as well as renames. See also --find-copies-harder. If n is specified, it
has the same meaning as for -M<n>.
--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. Giving more than one -C option
has the same effect.
-D, --irreversible-delete
Omit the preimage for deletes, i.e. print only the header but not the diff between the
preimage and /dev/null. The resulting patch is not meant to be applied with patch or
git apply; this is solely for people who want to just concentrate on reviewing the
text after the change. In addition, the output obviously lacks enough information to
apply such a patch in reverse, even manually, hence the name of the option.
When used together with -B, omit also the preimage in the deletion part of a
delete/create pair.
-l<num>
The -M and -C options involve some preliminary steps that can detect subsets of
renames/copies cheaply, followed by an exhaustive fallback portion that compares all
remaining unpaired destinations to all relevant sources. (For renames, only remaining
unpaired sources are relevant; for copies, all original sources are relevant.) For N
sources and destinations, this exhaustive check is O(N^2). This option prevents the
exhaustive portion of rename/copy detection from running if the number of
source/destination files involved exceeds the specified number. Defaults to
diff.renameLimit. Note that a value of 0 is treated as unlimited.
--diff-filter=[(A|C|D|M|R|T|U|X|B)...[*]]
Select only files that are Added (A), Copied (C), Deleted (D), Modified (M), Renamed
(R), have their type (i.e. regular file, symlink, submodule, ...) changed (T), are
Unmerged (U), are Unknown (X), or have had their pairing Broken (B). Any combination
of the filter characters (including none) can be used. When * (All-or-none) is added
to the combination, all paths are selected if there is any file that matches other
criteria in the comparison; if there is no file that matches other criteria, nothing
is selected.
Also, these upper-case letters can be downcased to exclude. E.g. --diff-filter=ad
excludes added and deleted paths.
Note that not all diffs can feature all types. For instance, copied and renamed
entries cannot appear if detection for those types is disabled.
-S<string>
Look for differences that change the number of occurrences of the specified string
(i.e. addition/deletion) in a file. Intended for the scripter’s use.
It is useful when you’re looking for an exact block of code (like a struct), and want
to know the history of that block since it first came into being: use the feature
iteratively to feed the interesting block in the preimage back into -S, and keep going
until you get the very first version of the block.
Binary files are searched as well.
-G<regex>
Look for differences whose patch text contains added/removed lines that match <regex>.
To illustrate the difference between -S<regex> --pickaxe-regex and -G<regex>, consider
a commit with the following diff in the same file:
+ return frotz(nitfol, two->ptr, 1, 0);
...
- hit = frotz(nitfol, mf2.ptr, 1, 0);
While git log -G"frotz\(nitfol" will show this commit, git log -S"frotz\(nitfol"
--pickaxe-regex will not (because the number of occurrences of that string did not
change).
Unless --text is supplied patches of binary files without a textconv filter will be
ignored.
See the pickaxe entry in gitdiffcore(7) for more information.
--find-object=<object-id>
Look for differences that change the number of occurrences of the specified object.
Similar to -S, just the argument is different in that it doesn’t search for a specific
string but for a specific object id.
The object can be a blob or a submodule commit. It implies the -t option in git-log to
also find trees.
--pickaxe-all
When -S or -G finds a change, show all the changes in that changeset, not just the
files that contain the change in <string>.
--pickaxe-regex
Treat the <string> given to -S as an extended POSIX regular expression to match.
-O<orderfile>
Control the order in which files appear in the output. This overrides the
diff.orderFile configuration variable (see git-config(1)). To cancel diff.orderFile,
use -O/dev/null.
The output order is determined by the order of glob patterns in <orderfile>. All files
with pathnames that match the first pattern are output first, all files with pathnames
that match the second pattern (but not the first) are output next, and so on. All
files with pathnames that do not match any pattern are output last, as if there was an
implicit match-all pattern at the end of the file. If multiple pathnames have the same
rank (they match the same pattern but no earlier patterns), their output order
relative to each other is the normal order.
<orderfile> is parsed as follows:
• Blank lines are ignored, so they can be used as separators for readability.
• Lines starting with a hash ("#") are ignored, so they can be used for comments.
Add a backslash ("\") to the beginning of the pattern if it starts with a hash.
• Each other line contains a single pattern.
Patterns have the same syntax and semantics as patterns used for fnmatch(3) without
the FNM_PATHNAME flag, except a pathname also matches a pattern if removing any number
of the final pathname components matches the pattern. For example, the pattern
"foo*bar" matches "fooasdfbar" and "foo/bar/baz/asdf" but not "foobarx".
--skip-to=<file>, --rotate-to=<file>
Discard the files before the named <file> from the output (i.e. skip to), or move
them to the end of the output (i.e. rotate to). These options were invented primarily
for the use of the git difftool command, and may not be very useful otherwise.
-R
Swap two inputs; that is, show differences from index or on-disk file to tree
contents.
--relative[=<path>], --no-relative
When run from a subdirectory of the project, it can be told to exclude changes outside
the directory and show pathnames relative to it with this option. When you are not in
a subdirectory (e.g. in a bare repository), you can name which subdirectory to make
the output relative to by giving a <path> as an argument. --no-relative can be used
to countermand both diff.relative config option and previous --relative.
-a, --text
Treat all files as text.
--ignore-cr-at-eol
Ignore carriage-return at the end of line when doing a comparison.
--ignore-space-at-eol
Ignore changes in whitespace at EOL.
-b, --ignore-space-change
Ignore changes in amount of whitespace. This ignores whitespace at line end, and
considers all other sequences of one or more whitespace characters to be equivalent.
-w, --ignore-all-space
Ignore whitespace when comparing lines. This ignores differences even if one line has
whitespace where the other line has none.
--ignore-blank-lines
Ignore changes whose lines are all blank.
-I<regex>, --ignore-matching-lines=<regex>
Ignore changes whose all lines match <regex>. This option may be specified more than
once.
--inter-hunk-context=<lines>
Show the context between diff hunks, up to the specified number of lines, thereby
fusing hunks that are close to each other. Defaults to diff.interHunkContext or 0 if
the config option is unset.
-W, --function-context
Show whole function as context lines for each change. The function names are
determined in the same way as git diff works out patch hunk headers (see Defining a
custom hunk-header in gitattributes(5)).
--exit-code
Make the program exit with codes similar to diff(1). That is, it exits with 1 if there
were differences and 0 means no differences.
--quiet
Disable all output of the program. Implies --exit-code.
--ext-diff
Allow an external diff helper to be executed. If you set an external diff driver with
gitattributes(5), you need to use this option with git-log(1) and friends.
--no-ext-diff
Disallow external diff drivers.
--textconv, --no-textconv
Allow (or disallow) external text conversion filters to be run when comparing binary
files. See gitattributes(5) for details. Because textconv filters are typically a
one-way conversion, the resulting diff is suitable for human consumption, but cannot
be applied. For this reason, textconv filters are enabled by default only for git-
diff(1) and git-log(1), but not for git-format-patch(1) or diff plumbing commands.
--ignore-submodules[=<when>]
Ignore changes to submodules in the diff generation. <when> can be either "none",
"untracked", "dirty" or "all", which is the default. Using "none" will consider the
submodule modified when it either contains untracked or modified files or its HEAD
differs from the commit recorded in the superproject and can be used to override any
settings of the ignore option in git-config(1) or gitmodules(5). When "untracked" is
used submodules are not considered dirty when they only contain untracked content (but
they are still scanned for modified content). Using "dirty" ignores all changes to the
work tree of submodules, only changes to the commits stored in the superproject are
shown (this was the behavior until 1.7.0). Using "all" hides all changes to
submodules.
--src-prefix=<prefix>
Show the given source prefix instead of "a/".
--dst-prefix=<prefix>
Show the given destination prefix instead of "b/".
--no-prefix
Do not show any source or destination prefix.
--default-prefix
Use the default source and destination prefixes ("a/" and "b/"). This overrides
configuration variables such as diff.noprefix, diff.srcPrefix, diff.dstPrefix, and
diff.mnemonicPrefix (see git-config(1)).
--line-prefix=<prefix>
Prepend an additional prefix to every line of output.
--ita-invisible-in-index
By default entries added by "git add -N" appear as an existing empty file in "git
diff" and a new file in "git diff --cached". This option makes the entry appear as a
new file in "git diff" and non-existent in "git diff --cached". This option could be
reverted with --ita-visible-in-index. Both options are experimental and could be
removed in future.
For more detailed explanation on these common options, see also gitdiffcore(7).
<tree-ish>
The id of a tree object to diff against.
--cached
Do not consider the on-disk file at all.
--merge-base
Instead of comparing <tree-ish> directly, use the merge base between <tree-ish> and
HEAD instead. <tree-ish> must be a commit.
-m
By default, files recorded in the index but not checked out are reported as deleted.
This flag makes git diff-index say that all non-checked-out files are up to date.
RAW OUTPUT FORMAT
The raw output format from "git-diff-index", "git-diff-tree", "git-diff-files" and "git
diff --raw" are very similar.
These commands all compare two sets of things; what is compared differs:
git-diff-index <tree-ish>
compares the <tree-ish> and the files on the filesystem.
git-diff-index --cached <tree-ish>
compares the <tree-ish> and the index.
git-diff-tree [-r] <tree-ish-1> <tree-ish-2> [<pattern>...]
compares the trees named by the two arguments.
git-diff-files [<pattern>...]
compares the index and the files on the filesystem.
The "git-diff-tree" command begins its output by printing the hash of what is being
compared. After that, all the commands print one output line per changed file.
An output line is formatted this way:
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:
1. a colon.
2. mode for "src"; 000000 if creation or unmerged.
3. a space.
4. mode for "dst"; 000000 if deletion or unmerged.
5. a space.
6. sha1 for "src"; 0{40} if creation or unmerged.
7. a space.
8. sha1 for "dst"; 0{40} if deletion, unmerged or "work tree out of sync with the index".
9. a space.
10. status, followed by optional "score" number.
11. a tab or a NUL when -z option is used.
12. path for "src"
13. a tab or a NUL when -z option is used; only exists for C or R.
14. path for "dst"; only exists for C or R.
15. an LF or a NUL when -z option is used, to terminate the record.
Possible status letters are:
• A: addition of a file
• C: copy of a file into a new one
• D: deletion of a file
• M: modification of the contents or mode of a file
• R: renaming of a file
• T: change in the type of the file (regular file, symbolic link or submodule)
• U: file is unmerged (you must complete the merge before it can be committed)
• X: "unknown" change type (most probably a bug, please report it)
Status letters C and R are always followed by a score (denoting the percentage of
similarity between the source and target of the move or copy). Status letter M may be
followed by a score (denoting the percentage of dissimilarity) for file rewrites.
The sha1 for "dst" is shown as all 0’s if a file on the filesystem is out of sync with the
index.
Example:
:100644 100644 5be4a4a 0000000 M file.c
Without the -z option, pathnames with "unusual" characters are quoted as explained for the
configuration variable core.quotePath (see git-config(1)). Using -z the filename is output
verbatim and the line is terminated by a NUL byte.
DIFF FORMAT FOR MERGES
"git-diff-tree", "git-diff-files" and "git-diff --raw" can take -c or --cc option to
generate diff output also for merge commits. The output differs from the format described
above in the following way:
1. there is a colon for each parent
2. there are more "src" modes and "src" sha1
3. status is concatenated status characters for each parent
4. no optional "score" number
5. tab-separated pathname(s) of the file
For -c and --cc, only the destination or final path is shown even if the file was renamed
on any side of history. With --combined-all-paths, the name of the path in each parent is
shown followed by the name of the path in the merge commit.
Examples for -c and --cc without --combined-all-paths:
::100644 100644 100644 fabadb8 cc95eb0 4866510 MM desc.c
::100755 100755 100755 52b7a2d 6d1ac04 d2ac7d7 RM bar.sh
::100644 100644 100644 e07d6c5 9042e82 ee91881 RR phooey.c
Examples when --combined-all-paths added to either -c or --cc:
::100644 100644 100644 fabadb8 cc95eb0 4866510 MM desc.c desc.c desc.c
::100755 100755 100755 52b7a2d 6d1ac04 d2ac7d7 RM foo.sh bar.sh bar.sh
::100644 100644 100644 e07d6c5 9042e82 ee91881 RR fooey.c fuey.c phooey.c
Note that combined diff lists only files which were modified from all parents.
GENERATING PATCH TEXT WITH -P
Running git-diff(1), git-log(1), git-show(1), git-diff-index(1), git-diff-tree(1), or git-
diff-files(1) with the -p option produces patch text. You can customize the creation of
patch text via the GIT_EXTERNAL_DIFF and the GIT_DIFF_OPTS environment variables (see
git(1)), and the diff attribute (see gitattributes(5)).
What the -p option produces is slightly different from the traditional diff format:
1. It is preceded by a "git diff" header that looks like this:
diff --git a/file1 b/file2
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 the a/ or b/
filenames.
When a 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 the rename/copy produces, respectively.
2. It is followed by one or more extended header lines:
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>
File modes are printed as 6-digit octal numbers including the file type and file
permission bits.
Path names in extended headers do not include the a/ and b/ prefixes.
The similarity index is the percentage of unchanged lines, and the dissimilarity index
is the percentage of changed lines. It is a rounded down integer, followed by a
percent sign. The similarity index value of 100% is thus reserved for two equal files,
while 100% dissimilarity means that no line from the old file made it into the new
one.
The index line includes the blob object names before and after the change. The <mode>
is included if the file mode does not change; otherwise, separate lines indicate the
old and the new mode.
3. Pathnames with "unusual" characters are quoted as explained for the configuration
variable core.quotePath (see git-config(1)).
4. All the file1 files in the output refer to files before the commit, and all the file2
files refer to files after the commit. It is incorrect to apply each change to each
file sequentially. For example, this patch will swap a and b:
diff --git a/a b/b
rename from a
rename to b
diff --git a/b b/a
rename from b
rename to a
5. Hunk headers mention the name of the function to which the hunk applies. See "Defining
a custom hunk-header" in gitattributes(5) for details of how to tailor this to
specific languages.
COMBINED DIFF FORMAT
Any diff-generating command can take the -c or --cc option to produce a combined diff when
showing a merge. This is the default format when showing merges with git-diff(1) or git-
show(1). Note also that you can give suitable --diff-merges option to any of these
commands to force generation of diffs in a specific format.
A "combined diff" format looks like this:
diff --combined describe.c
index fabadb8,cc95eb0..4866510
--- a/describe.c
+++ b/describe.c
@@@ -98,20 -98,12 +98,20 @@@
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;
struct commit_list *list;
static int initialized = 0;
struct commit_name *n;
+ if (get_sha1(arg, sha1) < 0)
+ usage(describe_usage);
+ cmit = lookup_commit_reference(sha1);
+ if (!cmit)
+ usage(describe_usage);
+
if (!initialized) {
initialized = 1;
for_each_ref(get_name);
1. It is preceded by a "git diff" header, that looks like this (when the -c option is
used):
diff --combined file
or like this (when the --cc option is used):
diff --cc file
2. It is followed by one or more extended header lines (this example shows a merge with
two parents):
index <hash>,<hash>..<hash>
mode <mode>,<mode>..<mode>
new file mode <mode>
deleted file mode <mode>,<mode>
The mode <mode>,<mode>..<mode> line appears only if at least one of the <mode> is
different from the rest. Extended headers with information about detected content
movement (renames and copying detection) are designed to work with the diff of two
<tree-ish> and are not used by combined diff format.
3. It is followed by a two-line from-file/to-file header:
--- a/file
+++ b/file
Similar to the two-line header for the traditional unified diff format, /dev/null is
used to signal created or deleted files.
However, if the --combined-all-paths option is provided, instead of a two-line
from-file/to-file, you get an N+1 line from-file/to-file header, where N is the number
of parents in the merge commit:
--- a/file
--- a/file
--- a/file
+++ b/file
This extended format can be useful if rename or copy detection is active, to allow you
to see the original name of the file in different parents.
4. Chunk header format is modified to prevent people from accidentally feeding it to
patch -p1. Combined diff format was created for review of merge commit changes, and
was not meant to be applied. The change is similar to the change in the extended index
header:
@@@ <from-file-range> <from-file-range> <to-file-range> @@@
There are (number of parents + 1) @ characters in the chunk header for combined diff
format.
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 result. A + character in the column N means that the line appears in the result,
and fileN does not have that line (in other words, the line was added, from the point of
view of that parent).
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 or file2). Also, eight 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").
OTHER DIFF FORMATS
The --summary option describes newly added, deleted, renamed and copied files. The --stat
option adds diffstat(1) graph to the output. These options can be combined with other
options, such as -p, and are meant for human consumption.
When showing a change that involves a rename or a copy, --stat output formats the
pathnames compactly by combining common prefix and suffix of the pathnames. For example, a
change that moves arch/i386/Makefile to arch/x86/Makefile while modifying 4 lines will be
shown like this:
arch/{i386 => x86}/Makefile | 4 +--
The --numstat option gives the diffstat(1) information but is designed for easier machine
consumption. An entry in --numstat output looks like this:
1 2 README
3 1 arch/{i386 => x86}/Makefile
That is, from left to right:
1. the number of added lines;
2. a tab;
3. the number of deleted lines;
4. a tab;
5. pathname (possibly with rename/copy information);
6. a newline.
When -z output option is in effect, the output is formatted this way:
1 2 README NUL
3 1 NUL arch/i386/Makefile NUL arch/x86/Makefile NUL
That is:
1. the number of added lines;
2. a tab;
3. the number of deleted lines;
4. a tab;
5. a NUL (only exists if renamed/copied);
6. pathname in preimage;
7. a NUL (only exists if renamed/copied);
8. pathname in postimage (only exists if renamed/copied);
9. a NUL.
The extra NUL before the preimage path in renamed case is to allow scripts that read the
output to tell if the current record being read is a single-path record or a rename/copy
record without reading ahead. After reading added and deleted lines, reading up to NUL
would yield the pathname, but if that is NUL, the record will show two paths.
OPERATING MODES
You can choose whether you want to trust the index file entirely (using the --cached flag)
or ask the diff logic to show any files that don’t match the stat state as being
"tentatively changed". Both of these operations are very useful indeed.
CACHED MODE
If --cached is specified, it allows you to ask:
show me the differences between HEAD and the current index
contents (the ones I'd write using 'git write-tree')
For example, let’s say that you have worked on your working directory, updated some files
in the index and are ready to commit. You want to see exactly what you are going to
commit, without having to write a new tree object and compare it that way, and to do that,
you just do
git diff-index --cached HEAD
Example: let’s say I had renamed commit.c to git-commit.c, and I had done an update-index
to make that effective in the index file. git diff-files wouldn’t show anything at all,
since the index file matches my working directory. But doing a git diff-index does:
torvalds@ppc970:~/git> git diff-index --cached HEAD
:100644 000000 4161aecc6700a2eb579e842af0b7f22b98443f74 0000000000000000000000000000000000000000 D commit.c
:000000 100644 0000000000000000000000000000000000000000 4161aecc6700a2eb579e842af0b7f22b98443f74 A git-commit.c
You can see easily that the above is a rename.
In fact, git diff-index --cached should always be entirely equivalent to actually doing a
git write-tree and comparing that. Except this one is much nicer for the case where you
just want to check where you are.
So doing a git diff-index --cached is basically very useful when you are asking yourself
"what have I already marked for being committed, and what’s the difference to a previous
tree".
NON-CACHED MODE
The "non-cached" mode takes a different approach, and is potentially the more useful of
the two in that what it does can’t be emulated with a git write-tree + git diff-tree. Thus
that’s the default mode. The non-cached version asks the question:
show me the differences between HEAD and the currently checked out
tree - index contents _and_ files that aren't up to date
which is obviously a very useful question too, since that tells you what you could commit.
Again, the output matches the git diff-tree -r output to a tee, but with a twist.
The twist is that if some file doesn’t match the index, we don’t have a backing store
thing for it, and we use the magic "all-zero" sha1 to show that. So let’s say that you
have edited kernel/sched.c, but have not actually done a git update-index on it yet -
there is no "object" associated with the new state, and you get:
torvalds@ppc970:~/v2.6/linux> git diff-index --abbrev HEAD
:100644 100644 7476bb5ba 000000000 M kernel/sched.c
i.e., it shows that the tree has changed, and that kernel/sched.c is not up to date and
may contain new stuff. The all-zero sha1 means that to get the real diff, you need to look
at the object in the working directory directly rather than do an object-to-object diff.
Note
As with other commands of this type, git diff-index does not actually look at the
contents of the file at all. So maybe kernel/sched.c hasn’t actually changed, and it’s
just that you touched it. In either case, it’s a note that you need to git
update-index it to make the index be in sync.
Note
You can have a mixture of files show up as "has been updated" and "is still dirty in
the working directory" together. You can always tell which file is in which state,
since the "has been updated" ones show a valid sha1, and the "not in sync with the
index" ones will always have the special all-zero sha1.
GIT
Part of the git(1) suite