git-show(1)

# git-show(1) Manual Page

## NAME

git-show - Show various types of objects

## SYNOPSIS

    git show [options] <object>…

## DESCRIPTION

Shows one or more objects (blobs, trees, tags and commits).

For commits it shows the log message and textual diff. It also presents the merge commit in a special format as produced by git diff-tree --cc.

For tags, it shows the tag message and the referenced objects.

For trees, it shows the names (equivalent to git ls-tree with --name-only).

For plain blobs, it shows the plain contents.

The command takes options applicable to the git diff-tree command to control how the changes the commit introduces are shown.

This manual page describes only the most frequently used options.

## OPTIONS

<object>…

  The names of objects to show. For a more complete list of ways to spell object names, see "SPECIFYING REVISIONS" section in gitrevisions(7).

--pretty[=<format>]
--format=<format>

  Pretty-print the contents of the commit logs in a given format, where <format> can be one of oneline, short, medium, full, fuller, email, raw and format:<string>. See the "PRETTY FORMATS" section for some additional details for each format. When omitted, the format defaults to medium.

  Note: you can specify the default pretty format in the repository configuration (see git-config(1)).

--abbrev-commit

  Instead of showing the full 40-byte hexadecimal commit object name, show only a partial prefix. Non default number of digits can be specified with "--abbrev=<n>" (which also modifies diff output, if it is displayed).

  This should make "--pretty=oneline" a whole lot more readable for people using 80-column terminals.

--no-abbrev-commit

  Show the full 40-byte hexadecimal commit object name. This negates `--abbrev-commit` and those options which imply it such as "--oneline". It also overrides the log.abbrevCommit variable.

--oneline

  This is a shorthand for "--pretty=oneline --abbrev-commit" used together.

--encoding=<encoding>

  The commit objects record the encoding used for the log message in their encoding header; this option can be used to tell the command to re-code the commit log message in the encoding preferred by the user. For non plumbing commands this defaults to UTF-8.

--notes[=<ref>]

  Show the notes (see git-notes(1)) that annotate the commit, when showing the commit log message. This is the default for `git log`, `git show` and `git whatchanged` commands when there is no `--pretty`, `--format` nor `--oneline` option given on the command line.

  By default, the notes shown are from the notes refs listed in the core.notesRef and notes.displayRef variables (or corresponding environment overrides). See git-config(1) for more details.

  With an optional <ref> argument, show this notes ref instead of the default notes ref(s). The ref is taken to be in `refs/notes/` if it is not qualified.

  Multiple --notes options can be combined to control which notes are being displayed. Examples: "--notes=foo" will show only notes from "refs/notes/foo"; "--notes=foo --notes" will show both notes from "refs/notes/foo" and from the default notes ref(s).

--no-notes

  Do not show notes. This negates the above `--notes` option, by resetting the list of notes refs from which notes are shown. Options are parsed in the order given on the command line, so e.g. "--notes --notes=foo --no-notes --notes=bar" will only show notes from "refs/notes/bar".

--show-notes[=<ref>]
--[no-]standard-notes

  These options are deprecated. Use the above --notes/--no-notes options instead.

--show-signature

  Check the validity of a signed commit object by passing the signature to `gpg --verify` and show the output.

## PRETTY FORMATS

If the commit is a merge, and if the pretty-format is not oneline, email or raw, an additional line is inserted before the Author: line. This line begins with "Merge: " and the sha1s of ancestral commits are printed, separated by spaces. Note that the listed commits may not necessarily be the list of the direct parent commits if you have limited your view of history: for example, if you are only interested in changes related to a certain directory or file.

There are several built-in formats, and you can define additional formats by setting a pretty.<name> config option to either another format name, or a format: string, as described below (see git-config(1)). Here are the details of the built-in formats:

- oneline

      <sha1> <title line>

  This is designed to be as compact as possible.

- short

      commit <sha1>
      Author: <author>

      <title line>

- medium

      commit <sha1>
      Author: <author>
      Date:   <author date>

      <title line>

      <full commit message>

- full

      commit <sha1>
      Author: <author>
      Commit: <committer>

      <title line>

      <full commit message>

- fuller

      commit <sha1>
      Author:     <author>
      AuthorDate: <author date>
      Commit:     <committer>
      CommitDate: <committer date>

      <title line>

      <full commit message>

- email

      From <sha1> <date>
      From: <author>
      Date: <author date>
      Subject: [PATCH] <title line>

      <full commit message>

- raw

  The raw format shows the entire commit exactly as stored in the commit object. Notably, the SHA-1s are displayed in full, regardless of whether --abbrev or --no-abbrev are used, and parents information show the true parent commits, without taking grafts nor history simplification into account.

- format:<string>

  The format:<string> format allows you to specify which information you want to show. It works a little bit like printf format, with the notable exception that you get a newline with %n instead of \n.

  E.g, format:"The author of %h was %an, %ar%nThe title was >>%s<<%n" would show something like this:

      The author of fe6e0ee was Junio C Hamano, 23 hours ago
      The title was >>t4119: test autocomputing -p<n> for traditional diff input.<<

  The placeholders are:

  - %H: commit hash

  - %h: abbreviated commit hash

  - %T: tree hash

  - %t: abbreviated tree hash

  - %P: parent hashes

  - %p: abbreviated parent hashes

  - %an: author name

  - %aN: author name (respecting .mailmap, see git-shortlog(1) or git-blame(1))

  - %ae: author email

  - %aE: author email (respecting .mailmap, see git-shortlog(1) or git-blame(1))

  - %ad: author date (format respects --date= option)

  - %aD: author date, RFC2822 style

  - %ar: author date, relative

  - %at: author date, UNIX timestamp

  - %ai: author date, ISO 8601 format

  - %cn: committer name

  - %cN: committer name (respecting .mailmap, see git-shortlog(1) or git-blame(1))

  - %ce: committer email

  - %cE: committer email (respecting .mailmap, see git-shortlog(1) or git-blame(1))

  - %cd: committer date

  - %cD: committer date, RFC2822 style

  - %cr: committer date, relative

  - %ct: committer date, UNIX timestamp

  - %ci: committer date, ISO 8601 format

  - %d: ref names, like the --decorate option of git-log(1)

  - %e: encoding

  - %s: subject

  - %f: sanitized subject line, suitable for a filename

  - %b: body

  - %B: raw body (unwrapped subject and body)

  - %N: commit notes

  - %GG: raw verification message from GPG for a signed commit

  - %G?: show "G" for a Good signature, "B" for a Bad signature, "U" for a good, untrusted signature and "N" for no signature

  - %GS: show the name of the signer for a signed commit

  - %GK: show the key used to sign a signed commit

  - %gD: reflog selector, e.g., `refs/stash@{1}`

  - %gd: shortened reflog selector, e.g., `stash@{1}`

  - %gn: reflog identity name

  - %gN: reflog identity name (respecting .mailmap, see git-shortlog(1) or git-blame(1))

  - %ge: reflog identity email

  - %gE: reflog identity email (respecting .mailmap, see git-shortlog(1) or git-blame(1))

  - %gs: reflog subject

  - %Cred: switch color to red

  - %Cgreen: switch color to green

  - %Cblue: switch color to blue

  - %Creset: reset color

  - %C(…): color specification, as described in color.branch.* config option; adding `auto,` at the beginning will emit color only when colors are enabled for log output (by `color.diff`, `color.ui`, or `--color`, and respecting the `auto` settings of the former if we are going to a terminal). `auto` alone (i.e. `%C(auto)`) will turn on auto coloring on the next placeholders until the color is switched again.

  - %m: left, right or boundary mark

  - %n: newline

  - %%: a raw %

  - %x00: print a byte from a hex code

  - %w([<w>[,<i1>[,<i2>]]]): switch line wrapping, like the -w option of git-shortlog(1).

  - %<(<N>[,trunc|ltrunc|mtrunc]): make the next placeholder take at least N columns, padding spaces on the right if necessary. Optionally truncate at the beginning (ltrunc), the middle (mtrunc) or the end (trunc) if the output is longer than N columns. Note that truncating only works correctly with N >= 2.

  - %<|(<N>): make the next placeholder take at least until Nth columns, padding spaces on the right if necessary

  - %>(<N>), %>|(<N>): similar to %<(<N>), %<|(<N>) respectively, but padding spaces on the left

  - %>>(<N>), %>>|(<N>): similar to %>(<N>), %>|(<N>) respectively, except that if the next placeholder takes more spaces than given and there are spaces on its left, use those spaces

  - %><(<N>), %><|(<N>): similar to % <(<N>), %<|(<N>) respectively, but padding both sides (i.e. the text is centered)

Note | Some placeholders may depend on other options given to the revision traversal engine. For example, the `%g*` reflog options will insert an empty string unless we are traversing reflog entries (e.g., by `git log -g`). The `%d` placeholder will use the "short" decoration format if `--decorate` was not already provided on the command line.

If you add a `+` (plus sign) after % of a placeholder, a line-feed is inserted immediately before the expansion if and only if the placeholder expands to a non-empty string.

If you add a `-` (minus sign) after % of a placeholder, line-feeds that immediately precede the expansion are deleted if and only if the placeholder expands to an empty string.

If you add a ` ` (space) after % of a placeholder, a space is inserted immediately before the expansion if and only if the placeholder expands to a non-empty string.

- tformat:

  The tformat: format works exactly like format:, except that it provides "terminator" semantics instead of "separator" semantics. In other words, each commit has the message terminator character (usually a newline) appended, rather than a separator placed between entries. This means that the final entry of a single-line format will be properly terminated with a new line, just as the "oneline" format does. For example:

      $ git log -2 --pretty=format:%h 4da45bef \
        | perl -pe '$_ .= " -- NO NEWLINE\n" unless /\n/'
      4da45be
      7134973 -- NO NEWLINE

      $ git log -2 --pretty=tformat:%h 4da45bef \
        | perl -pe '$_ .= " -- NO NEWLINE\n" unless /\n/'
      4da45be
      7134973

  In addition, any unrecognized string that has a `%` in it is interpreted as if it has `tformat:` in front of it. For example, these two are equivalent:

      $ git log -2 --pretty=tformat:%h 4da45bef
      $ git log -2 --pretty=%h 4da45bef

## COMMON DIFF OPTIONS

-p
-u
--patch

  Generate patch (see section on generating patches).

-s
--no-patch

  Suppress diff output. Useful for commands like `git show` that show the patch by default, or to cancel the effect of `--patch`.

-U<n>
--unified=<n>

  Generate diffs with <n> lines of context instead of the usual three. Implies `-p`.

--raw

  Generate the raw format.

--patch-with-raw

  Synonym for `-p --raw`.

--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.

--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 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. The width of the graph part can be limited by using `--stat-graph-width=<width>` (affects all commands generating a stat graph) or by setting `diff.statGraphWidth=<width>` (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>`.

--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.

--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`.

--summary

  Output a condensed summary of extended header information such as creations, renames and mode changes.

--patch-with-stat

  Synonym for `-p --stat`.

-z

  Separate the commits with NULs instead of with new newlines.

  Also, when `--raw` or `--numstat` has been given, do not munge pathnames and use NULs as output field terminators.

  Without this option, each pathname output will have TAB, LF, double quotes, and backslash characters replaced with `\t`, `\n`, `\"`, and `\\`, respectively, and the pathname will be enclosed in double quotes if any of those replacements occurred.

--name-only

  Show only names of changed files.

--name-status

  Show only names and status of changed files. See the description of the `--diff-filter` option on what the status letters mean.

--submodule[=<format>]

  Specify how differences in submodules are shown. When `--submodule` or `--submodule=log` is given, the log format is used. This format lists the commits in the range like git-submodule(1) `summary` does. Omitting the `--submodule` option or specifying `--submodule=short`, uses the short format. This format just shows the names of the commits at the beginning and end of the range. Can be tweaked via the `diff.submodule` configuration variable.

--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`.

--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.

  The regex can also be set via a diff driver or configuration option, see gitattributes(1) 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.

--check

  Warn if changes introduce whitespace errors. What are considered whitespace errors is controlled by `core.whitespace` configuration. By default, trailing whitespaces (including lines that solely consist 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.

--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`.

--abbrev[=<n>]

  Instead of showing the full 40-byte hexadecimal object name in diff-raw format output and diff-tree header lines, show only a partial prefix. This is independent of the `--full-index` option above, which controls the diff-patch output format. 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>]

  If generating diffs, detect and report renames for each commit. For following files across renames while traversing history, see `--follow`. 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` nor `git apply`; this is solely for people who want to just concentrate on reviewing the text after the change. In addition, the output obviously lack 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 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.

--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.

-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.

-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 !regexec(regexp, two->ptr, 1, &regmatch, 0);
      ...
      -    hit = !regexec(regexp, mf2.ptr, 1, &regmatch, 0);

  While `git log -G"regexec\(regexp"` will show this commit, `git log -S"regexec\(regexp" --pickaxe-regex` will not (because the number of occurrences of that string did not change).

  See the pickaxe entry in gitdiffcore(7) for more information.

--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>

  Output the patch in the order specified in the <orderfile>, which has one shell glob pattern per line.

-R

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

--relative[=<path>]

  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.

-a
--text

  Treat all files as text.

--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.

--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.

-W
--function-context

  Show whole surrounding functions of changes.

--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.

For more detailed explanation on these common options, see also gitdiffcore(7).

## Generating patches with -p

When "git-diff-index", "git-diff-tree", or "git-diff-files" are run with a -p option, "git diff" without the --raw option, or "git log" with the "-p" option, they do not produce the output described above; instead they produce a patch file. You can customize the creation of such patches via the GIT_EXTERNAL_DIFF and the GIT_DIFF_OPTS environment variables.

What the -p option produces is slightly different from the traditional diff format:

1. It is preceded with 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 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.

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 SHA-1 checksum 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. TAB, LF, double quote and backslash characters in pathnames are represented as `\t`, `\n`, `\"` and `\\`, respectively. If there is need for such substitution then the whole pathname is put in double quotes.

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

## 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 the `-m’ option to any of these commands to force generation of diffs with individual parents of a merge.

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 with a "git diff" header, that looks like this (when -c option is used):

       diff --combined file

   or like this (when --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 contents movement (renames and copying detection) are designed to work with diff of two <tree-ish> and are not used by combined diff format.

3. It is followed by two-line from-file/to-file header

       --- a/file
       +++ b/file

   Similar to two-line header for traditional unified diff format, `/dev/null` is used to signal created or deleted files.

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 for apply. 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 nor 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").

## EXAMPLES

`git show v1.0.0`

  Shows the tag `v1.0.0`, along with the object the tags points at.

`git show v1.0.0^{tree}`

  Shows the tree pointed to by the tag `v1.0.0`.

`git show -s --format=%s v1.0.0^{commit}`

  Shows the subject of the commit pointed to by the tag `v1.0.0`.

`git show next~10:Documentation/README`

  Shows the contents of the file `Documentation/README` as they were current in the 10th last commit of the branch `next`.

`git show master:Makefile master:t/Makefile`

  Concatenates the contents of said Makefiles in the head of the branch `master`.

## Discussion

At the core level, Git is character encoding agnostic.

- The pathnames recorded in the index and in the tree objects are treated as uninterpreted sequences of non-NUL bytes. What readdir(2) returns are what are recorded and compared with the data Git keeps track of, which in turn are expected to be what lstat(2) and creat(2) accepts. There is no such thing as pathname encoding translation.

- The contents of the blob objects are uninterpreted sequences of bytes. There is no encoding translation at the core level.

- The commit log messages are uninterpreted sequences of non-NUL bytes.

Although we encourage that the commit log messages are encoded in UTF-8, both the core and Git Porcelain are designed not to force UTF-8 on projects. If all participants of a particular project find it more convenient to use legacy encodings, Git does not forbid it. However, there are a few things to keep in mind.

1. git commit and git commit-tree issues a warning if the commit log message given to it does not look like a valid UTF-8 string, unless you explicitly say your project uses a legacy encoding. The way to say this is to have i18n.commitencoding in `.git/config` file, like this:

       [i18n]
               commitencoding = ISO-8859-1

   Commit objects created with the above setting record the value of `i18n.commitencoding` in its `encoding` header. This is to help other people who look at them later. Lack of this header implies that the commit log message is encoded in UTF-8.

2. git log, git show, git blame and friends look at the `encoding` header of a commit object, and try to re-code the log message into UTF-8 unless otherwise specified. You can specify the desired output encoding with `i18n.logoutputencoding` in `.git/config` file, like this:

       [i18n]
               logoutputencoding = ISO-8859-1

   If you do not have this configuration variable, the value of `i18n.commitencoding` is used instead.

Note that we deliberately chose not to re-code the commit log message when a commit is made to force UTF-8 at the commit object level, because re-coding to UTF-8 is not necessarily a reversible operation.

## GIT

Part of the git(1) suite