Documentation / diff-options.txton commit graph: add commit graph design document (ae30d7b)
   1// Please don't remove this comment as asciidoc behaves badly when
   2// the first non-empty line is ifdef/ifndef. The symptom is that
   3// without this comment the <git-diff-core> attribute conditionally
   4// defined below ends up being defined unconditionally.
   5// Last checked with asciidoc 7.0.2.
   6
   7ifndef::git-format-patch[]
   8ifndef::git-diff[]
   9ifndef::git-log[]
  10:git-diff-core: 1
  11endif::git-log[]
  12endif::git-diff[]
  13endif::git-format-patch[]
  14
  15ifdef::git-format-patch[]
  16-p::
  17--no-stat::
  18        Generate plain patches without any diffstats.
  19endif::git-format-patch[]
  20
  21ifndef::git-format-patch[]
  22-p::
  23-u::
  24--patch::
  25        Generate patch (see section on generating patches).
  26ifdef::git-diff[]
  27        This is the default.
  28endif::git-diff[]
  29
  30-s::
  31--no-patch::
  32        Suppress diff output. Useful for commands like `git show` that
  33        show the patch by default, or to cancel the effect of `--patch`.
  34endif::git-format-patch[]
  35
  36-U<n>::
  37--unified=<n>::
  38        Generate diffs with <n> lines of context instead of
  39        the usual three.
  40ifndef::git-format-patch[]
  41        Implies `-p`.
  42endif::git-format-patch[]
  43
  44ifndef::git-format-patch[]
  45--raw::
  46ifndef::git-log[]
  47        Generate the diff in raw format.
  48ifdef::git-diff-core[]
  49        This is the default.
  50endif::git-diff-core[]
  51endif::git-log[]
  52ifdef::git-log[]
  53        For each commit, show a summary of changes using the raw diff
  54        format. See the "RAW OUTPUT FORMAT" section of
  55        linkgit:git-diff[1]. This is different from showing the log
  56        itself in raw format, which you can achieve with
  57        `--format=raw`.
  58endif::git-log[]
  59endif::git-format-patch[]
  60
  61ifndef::git-format-patch[]
  62--patch-with-raw::
  63        Synonym for `-p --raw`.
  64endif::git-format-patch[]
  65
  66--indent-heuristic::
  67        Enable the heuristic that shift diff hunk boundaries to make patches
  68        easier to read. This is the default.
  69
  70--no-indent-heuristic::
  71        Disable the indent heuristic.
  72
  73--minimal::
  74        Spend extra time to make sure the smallest possible
  75        diff is produced.
  76
  77--patience::
  78        Generate a diff using the "patience diff" algorithm.
  79
  80--histogram::
  81        Generate a diff using the "histogram diff" algorithm.
  82
  83--anchored=<text>::
  84        Generate a diff using the "anchored diff" algorithm.
  85+
  86This option may be specified more than once.
  87+
  88If a line exists in both the source and destination, exists only once,
  89and starts with this text, this algorithm attempts to prevent it from
  90appearing as a deletion or addition in the output. It uses the "patience
  91diff" algorithm internally.
  92
  93--diff-algorithm={patience|minimal|histogram|myers}::
  94        Choose a diff algorithm. The variants are as follows:
  95+
  96--
  97`default`, `myers`;;
  98        The basic greedy diff algorithm. Currently, this is the default.
  99`minimal`;;
 100        Spend extra time to make sure the smallest possible diff is
 101        produced.
 102`patience`;;
 103        Use "patience diff" algorithm when generating patches.
 104`histogram`;;
 105        This algorithm extends the patience algorithm to "support
 106        low-occurrence common elements".
 107--
 108+
 109For instance, if you configured diff.algorithm variable to a
 110non-default value and want to use the default one, then you
 111have to use `--diff-algorithm=default` option.
 112
 113--stat[=<width>[,<name-width>[,<count>]]]::
 114        Generate a diffstat. By default, as much space as necessary
 115        will be used for the filename part, and the rest for the graph
 116        part. Maximum width defaults to terminal width, or 80 columns
 117        if not connected to a terminal, and can be overridden by
 118        `<width>`. The width of the filename part can be limited by
 119        giving another width `<name-width>` after a comma. The width
 120        of the graph part can be limited by using
 121        `--stat-graph-width=<width>` (affects all commands generating
 122        a stat graph) or by setting `diff.statGraphWidth=<width>`
 123        (does not affect `git format-patch`).
 124        By giving a third parameter `<count>`, you can limit the
 125        output to the first `<count>` lines, followed by `...` if
 126        there are more.
 127+
 128These parameters can also be set individually with `--stat-width=<width>`,
 129`--stat-name-width=<name-width>` and `--stat-count=<count>`.
 130
 131--numstat::
 132        Similar to `--stat`, but shows number of added and
 133        deleted lines in decimal notation and pathname without
 134        abbreviation, to make it more machine friendly.  For
 135        binary files, outputs two `-` instead of saying
 136        `0 0`.
 137
 138--shortstat::
 139        Output only the last line of the `--stat` format containing total
 140        number of modified files, as well as number of added and deleted
 141        lines.
 142
 143--dirstat[=<param1,param2,...>]::
 144        Output the distribution of relative amount of changes for each
 145        sub-directory. The behavior of `--dirstat` can be customized by
 146        passing it a comma separated list of parameters.
 147        The defaults are controlled by the `diff.dirstat` configuration
 148        variable (see linkgit:git-config[1]).
 149        The following parameters are available:
 150+
 151--
 152`changes`;;
 153        Compute the dirstat numbers by counting the lines that have been
 154        removed from the source, or added to the destination. This ignores
 155        the amount of pure code movements within a file.  In other words,
 156        rearranging lines in a file is not counted as much as other changes.
 157        This is the default behavior when no parameter is given.
 158`lines`;;
 159        Compute the dirstat numbers by doing the regular line-based diff
 160        analysis, and summing the removed/added line counts. (For binary
 161        files, count 64-byte chunks instead, since binary files have no
 162        natural concept of lines). This is a more expensive `--dirstat`
 163        behavior than the `changes` behavior, but it does count rearranged
 164        lines within a file as much as other changes. The resulting output
 165        is consistent with what you get from the other `--*stat` options.
 166`files`;;
 167        Compute the dirstat numbers by counting the number of files changed.
 168        Each changed file counts equally in the dirstat analysis. This is
 169        the computationally cheapest `--dirstat` behavior, since it does
 170        not have to look at the file contents at all.
 171`cumulative`;;
 172        Count changes in a child directory for the parent directory as well.
 173        Note that when using `cumulative`, the sum of the percentages
 174        reported may exceed 100%. The default (non-cumulative) behavior can
 175        be specified with the `noncumulative` parameter.
 176<limit>;;
 177        An integer parameter specifies a cut-off percent (3% by default).
 178        Directories contributing less than this percentage of the changes
 179        are not shown in the output.
 180--
 181+
 182Example: The following will count changed files, while ignoring
 183directories with less than 10% of the total amount of changed files,
 184and accumulating child directory counts in the parent directories:
 185`--dirstat=files,10,cumulative`.
 186
 187--summary::
 188        Output a condensed summary of extended header information
 189        such as creations, renames and mode changes.
 190
 191ifndef::git-format-patch[]
 192--patch-with-stat::
 193        Synonym for `-p --stat`.
 194endif::git-format-patch[]
 195
 196ifndef::git-format-patch[]
 197
 198-z::
 199ifdef::git-log[]
 200        Separate the commits with NULs instead of with new newlines.
 201+
 202Also, when `--raw` or `--numstat` has been given, do not munge
 203pathnames and use NULs as output field terminators.
 204endif::git-log[]
 205ifndef::git-log[]
 206        When `--raw`, `--numstat`, `--name-only` or `--name-status` has been
 207        given, do not munge pathnames and use NULs as output field terminators.
 208endif::git-log[]
 209+
 210Without this option, pathnames with "unusual" characters are quoted as
 211explained for the configuration variable `core.quotePath` (see
 212linkgit:git-config[1]).
 213
 214--name-only::
 215        Show only names of changed files.
 216
 217--name-status::
 218        Show only names and status of changed files. See the description
 219        of the `--diff-filter` option on what the status letters mean.
 220
 221--submodule[=<format>]::
 222        Specify how differences in submodules are shown.  When specifying
 223        `--submodule=short` the 'short' format is used.  This format just
 224        shows the names of the commits at the beginning and end of the range.
 225        When `--submodule` or `--submodule=log` is specified, the 'log'
 226        format is used.  This format lists the commits in the range like
 227        linkgit:git-submodule[1] `summary` does.  When `--submodule=diff`
 228        is specified, the 'diff' format is used.  This format shows an
 229        inline diff of the changes in the submodule contents between the
 230        commit range.  Defaults to `diff.submodule` or the 'short' format
 231        if the config option is unset.
 232
 233--color[=<when>]::
 234        Show colored diff.
 235        `--color` (i.e. without '=<when>') is the same as `--color=always`.
 236        '<when>' can be one of `always`, `never`, or `auto`.
 237ifdef::git-diff[]
 238        It can be changed by the `color.ui` and `color.diff`
 239        configuration settings.
 240endif::git-diff[]
 241
 242--no-color::
 243        Turn off colored diff.
 244ifdef::git-diff[]
 245        This can be used to override configuration settings.
 246endif::git-diff[]
 247        It is the same as `--color=never`.
 248
 249--color-moved[=<mode>]::
 250        Moved lines of code are colored differently.
 251ifdef::git-diff[]
 252        It can be changed by the `diff.colorMoved` configuration setting.
 253endif::git-diff[]
 254        The <mode> defaults to 'no' if the option is not given
 255        and to 'zebra' if the option with no mode is given.
 256        The mode must be one of:
 257+
 258--
 259no::
 260        Moved lines are not highlighted.
 261default::
 262        Is a synonym for `zebra`. This may change to a more sensible mode
 263        in the future.
 264plain::
 265        Any line that is added in one location and was removed
 266        in another location will be colored with 'color.diff.newMoved'.
 267        Similarly 'color.diff.oldMoved' will be used for removed lines
 268        that are added somewhere else in the diff. This mode picks up any
 269        moved line, but it is not very useful in a review to determine
 270        if a block of code was moved without permutation.
 271zebra::
 272        Blocks of moved text of at least 20 alphanumeric characters
 273        are detected greedily. The detected blocks are
 274        painted using either the 'color.diff.{old,new}Moved' color or
 275        'color.diff.{old,new}MovedAlternative'. The change between
 276        the two colors indicates that a new block was detected.
 277dimmed_zebra::
 278        Similar to 'zebra', but additional dimming of uninteresting parts
 279        of moved code is performed. The bordering lines of two adjacent
 280        blocks are considered interesting, the rest is uninteresting.
 281--
 282
 283--word-diff[=<mode>]::
 284        Show a word diff, using the <mode> to delimit changed words.
 285        By default, words are delimited by whitespace; see
 286        `--word-diff-regex` below.  The <mode> defaults to 'plain', and
 287        must be one of:
 288+
 289--
 290color::
 291        Highlight changed words using only colors.  Implies `--color`.
 292plain::
 293        Show words as `[-removed-]` and `{+added+}`.  Makes no
 294        attempts to escape the delimiters if they appear in the input,
 295        so the output may be ambiguous.
 296porcelain::
 297        Use a special line-based format intended for script
 298        consumption.  Added/removed/unchanged runs are printed in the
 299        usual unified diff format, starting with a `+`/`-`/` `
 300        character at the beginning of the line and extending to the
 301        end of the line.  Newlines in the input are represented by a
 302        tilde `~` on a line of its own.
 303none::
 304        Disable word diff again.
 305--
 306+
 307Note that despite the name of the first mode, color is used to
 308highlight the changed parts in all modes if enabled.
 309
 310--word-diff-regex=<regex>::
 311        Use <regex> to decide what a word is, instead of considering
 312        runs of non-whitespace to be a word.  Also implies
 313        `--word-diff` unless it was already enabled.
 314+
 315Every non-overlapping match of the
 316<regex> is considered a word.  Anything between these matches is
 317considered whitespace and ignored(!) for the purposes of finding
 318differences.  You may want to append `|[^[:space:]]` to your regular
 319expression to make sure that it matches all non-whitespace characters.
 320A match that contains a newline is silently truncated(!) at the
 321newline.
 322+
 323For example, `--word-diff-regex=.` will treat each character as a word
 324and, correspondingly, show differences character by character.
 325+
 326The regex can also be set via a diff driver or configuration option, see
 327linkgit:gitattributes[5] or linkgit:git-config[1].  Giving it explicitly
 328overrides any diff driver or configuration setting.  Diff drivers
 329override configuration settings.
 330
 331--color-words[=<regex>]::
 332        Equivalent to `--word-diff=color` plus (if a regex was
 333        specified) `--word-diff-regex=<regex>`.
 334endif::git-format-patch[]
 335
 336--no-renames::
 337        Turn off rename detection, even when the configuration
 338        file gives the default to do so.
 339
 340ifndef::git-format-patch[]
 341--check::
 342        Warn if changes introduce conflict markers or whitespace errors.
 343        What are considered whitespace errors is controlled by `core.whitespace`
 344        configuration.  By default, trailing whitespaces (including
 345        lines that solely consist of whitespaces) and a space character
 346        that is immediately followed by a tab character inside the
 347        initial indent of the line are considered whitespace errors.
 348        Exits with non-zero status if problems are found. Not compatible
 349        with --exit-code.
 350
 351--ws-error-highlight=<kind>::
 352        Highlight whitespace errors in the `context`, `old` or `new`
 353        lines of the diff.  Multiple values are separated by comma,
 354        `none` resets previous values, `default` reset the list to
 355        `new` and `all` is a shorthand for `old,new,context`.  When
 356        this option is not given, and the configuration variable
 357        `diff.wsErrorHighlight` is not set, only whitespace errors in
 358        `new` lines are highlighted. The whitespace errors are colored
 359        whith `color.diff.whitespace`.
 360
 361endif::git-format-patch[]
 362
 363--full-index::
 364        Instead of the first handful of characters, show the full
 365        pre- and post-image blob object names on the "index"
 366        line when generating patch format output.
 367
 368--binary::
 369        In addition to `--full-index`, output a binary diff that
 370        can be applied with `git-apply`.
 371
 372--abbrev[=<n>]::
 373        Instead of showing the full 40-byte hexadecimal object
 374        name in diff-raw format output and diff-tree header
 375        lines, show only a partial prefix.  This is
 376        independent of the `--full-index` option above, which controls
 377        the diff-patch output format.  Non default number of
 378        digits can be specified with `--abbrev=<n>`.
 379
 380-B[<n>][/<m>]::
 381--break-rewrites[=[<n>][/<m>]]::
 382        Break complete rewrite changes into pairs of delete and
 383        create. This serves two purposes:
 384+
 385It affects the way a change that amounts to a total rewrite of a file
 386not as a series of deletion and insertion mixed together with a very
 387few lines that happen to match textually as the context, but as a
 388single deletion of everything old followed by a single insertion of
 389everything new, and the number `m` controls this aspect of the -B
 390option (defaults to 60%). `-B/70%` specifies that less than 30% of the
 391original should remain in the result for Git to consider it a total
 392rewrite (i.e. otherwise the resulting patch will be a series of
 393deletion and insertion mixed together with context lines).
 394+
 395When used with -M, a totally-rewritten file is also considered as the
 396source of a rename (usually -M only considers a file that disappeared
 397as the source of a rename), and the number `n` controls this aspect of
 398the -B option (defaults to 50%). `-B20%` specifies that a change with
 399addition and deletion compared to 20% or more of the file's size are
 400eligible for being picked up as a possible source of a rename to
 401another file.
 402
 403-M[<n>]::
 404--find-renames[=<n>]::
 405ifndef::git-log[]
 406        Detect renames.
 407endif::git-log[]
 408ifdef::git-log[]
 409        If generating diffs, detect and report renames for each commit.
 410        For following files across renames while traversing history, see
 411        `--follow`.
 412endif::git-log[]
 413        If `n` is specified, it is a threshold on the similarity
 414        index (i.e. amount of addition/deletions compared to the
 415        file's size). For example, `-M90%` means Git should consider a
 416        delete/add pair to be a rename if more than 90% of the file
 417        hasn't changed.  Without a `%` sign, the number is to be read as
 418        a fraction, with a decimal point before it.  I.e., `-M5` becomes
 419        0.5, and is thus the same as `-M50%`.  Similarly, `-M05` is
 420        the same as `-M5%`.  To limit detection to exact renames, use
 421        `-M100%`.  The default similarity index is 50%.
 422
 423-C[<n>]::
 424--find-copies[=<n>]::
 425        Detect copies as well as renames.  See also `--find-copies-harder`.
 426        If `n` is specified, it has the same meaning as for `-M<n>`.
 427
 428--find-copies-harder::
 429        For performance reasons, by default, `-C` option finds copies only
 430        if the original file of the copy was modified in the same
 431        changeset.  This flag makes the command
 432        inspect unmodified files as candidates for the source of
 433        copy.  This is a very expensive operation for large
 434        projects, so use it with caution.  Giving more than one
 435        `-C` option has the same effect.
 436
 437-D::
 438--irreversible-delete::
 439        Omit the preimage for deletes, i.e. print only the header but not
 440        the diff between the preimage and `/dev/null`. The resulting patch
 441        is not meant to be applied with `patch` or `git apply`; this is
 442        solely for people who want to just concentrate on reviewing the
 443        text after the change. In addition, the output obviously lacks
 444        enough information to apply such a patch in reverse, even manually,
 445        hence the name of the option.
 446+
 447When used together with `-B`, omit also the preimage in the deletion part
 448of a delete/create pair.
 449
 450-l<num>::
 451        The `-M` and `-C` options require O(n^2) processing time where n
 452        is the number of potential rename/copy targets.  This
 453        option prevents rename/copy detection from running if
 454        the number of rename/copy targets exceeds the specified
 455        number.
 456
 457ifndef::git-format-patch[]
 458--diff-filter=[(A|C|D|M|R|T|U|X|B)...[*]]::
 459        Select only files that are Added (`A`), Copied (`C`),
 460        Deleted (`D`), Modified (`M`), Renamed (`R`), have their
 461        type (i.e. regular file, symlink, submodule, ...) changed (`T`),
 462        are Unmerged (`U`), are
 463        Unknown (`X`), or have had their pairing Broken (`B`).
 464        Any combination of the filter characters (including none) can be used.
 465        When `*` (All-or-none) is added to the combination, all
 466        paths are selected if there is any file that matches
 467        other criteria in the comparison; if there is no file
 468        that matches other criteria, nothing is selected.
 469+
 470Also, these upper-case letters can be downcased to exclude.  E.g.
 471`--diff-filter=ad` excludes added and deleted paths.
 472+
 473Note that not all diffs can feature all types. For instance, diffs
 474from the index to the working tree can never have Added entries
 475(because the set of paths included in the diff is limited by what is in
 476the index).  Similarly, copied and renamed entries cannot appear if
 477detection for those types is disabled.
 478
 479-S<string>::
 480        Look for differences that change the number of occurrences of
 481        the specified string (i.e. addition/deletion) in a file.
 482        Intended for the scripter's use.
 483+
 484It is useful when you're looking for an exact block of code (like a
 485struct), and want to know the history of that block since it first
 486came into being: use the feature iteratively to feed the interesting
 487block in the preimage back into `-S`, and keep going until you get the
 488very first version of the block.
 489
 490-G<regex>::
 491        Look for differences whose patch text contains added/removed
 492        lines that match <regex>.
 493+
 494To illustrate the difference between `-S<regex> --pickaxe-regex` and
 495`-G<regex>`, consider a commit with the following diff in the same
 496file:
 497+
 498----
 499+    return !regexec(regexp, two->ptr, 1, &regmatch, 0);
 500...
 501-    hit = !regexec(regexp, mf2.ptr, 1, &regmatch, 0);
 502----
 503+
 504While `git log -G"regexec\(regexp"` will show this commit, `git log
 505-S"regexec\(regexp" --pickaxe-regex` will not (because the number of
 506occurrences of that string did not change).
 507+
 508See the 'pickaxe' entry in linkgit:gitdiffcore[7] for more
 509information.
 510
 511--find-object=<object-id>::
 512        Look for differences that change the number of occurrences of
 513        the specified object. Similar to `-S`, just the argument is different
 514        in that it doesn't search for a specific string but for a specific
 515        object id.
 516+
 517The object can be a blob or a submodule commit. It implies the `-t` option in
 518`git-log` to also find trees.
 519
 520--pickaxe-all::
 521        When `-S` or `-G` finds a change, show all the changes in that
 522        changeset, not just the files that contain the change
 523        in <string>.
 524
 525--pickaxe-regex::
 526        Treat the <string> given to `-S` as an extended POSIX regular
 527        expression to match.
 528
 529endif::git-format-patch[]
 530
 531-O<orderfile>::
 532        Control the order in which files appear in the output.
 533        This overrides the `diff.orderFile` configuration variable
 534        (see linkgit:git-config[1]).  To cancel `diff.orderFile`,
 535        use `-O/dev/null`.
 536+
 537The output order is determined by the order of glob patterns in
 538<orderfile>.
 539All files with pathnames that match the first pattern are output
 540first, all files with pathnames that match the second pattern (but not
 541the first) are output next, and so on.
 542All files with pathnames that do not match any pattern are output
 543last, as if there was an implicit match-all pattern at the end of the
 544file.
 545If multiple pathnames have the same rank (they match the same pattern
 546but no earlier patterns), their output order relative to each other is
 547the normal order.
 548+
 549<orderfile> is parsed as follows:
 550+
 551--
 552 - Blank lines are ignored, so they can be used as separators for
 553   readability.
 554
 555 - Lines starting with a hash ("`#`") are ignored, so they can be used
 556   for comments.  Add a backslash ("`\`") to the beginning of the
 557   pattern if it starts with a hash.
 558
 559 - Each other line contains a single pattern.
 560--
 561+
 562Patterns have the same syntax and semantics as patterns used for
 563fnmantch(3) without the FNM_PATHNAME flag, except a pathname also
 564matches a pattern if removing any number of the final pathname
 565components matches the pattern.  For example, the pattern "`foo*bar`"
 566matches "`fooasdfbar`" and "`foo/bar/baz/asdf`" but not "`foobarx`".
 567
 568ifndef::git-format-patch[]
 569-R::
 570        Swap two inputs; that is, show differences from index or
 571        on-disk file to tree contents.
 572
 573--relative[=<path>]::
 574        When run from a subdirectory of the project, it can be
 575        told to exclude changes outside the directory and show
 576        pathnames relative to it with this option.  When you are
 577        not in a subdirectory (e.g. in a bare repository), you
 578        can name which subdirectory to make the output relative
 579        to by giving a <path> as an argument.
 580endif::git-format-patch[]
 581
 582-a::
 583--text::
 584        Treat all files as text.
 585
 586--ignore-cr-at-eol::
 587        Ignore carrige-return at the end of line when doing a comparison.
 588
 589--ignore-space-at-eol::
 590        Ignore changes in whitespace at EOL.
 591
 592-b::
 593--ignore-space-change::
 594        Ignore changes in amount of whitespace.  This ignores whitespace
 595        at line end, and considers all other sequences of one or
 596        more whitespace characters to be equivalent.
 597
 598-w::
 599--ignore-all-space::
 600        Ignore whitespace when comparing lines.  This ignores
 601        differences even if one line has whitespace where the other
 602        line has none.
 603
 604--ignore-blank-lines::
 605        Ignore changes whose lines are all blank.
 606
 607--inter-hunk-context=<lines>::
 608        Show the context between diff hunks, up to the specified number
 609        of lines, thereby fusing hunks that are close to each other.
 610        Defaults to `diff.interHunkContext` or 0 if the config option
 611        is unset.
 612
 613-W::
 614--function-context::
 615        Show whole surrounding functions of changes.
 616
 617ifndef::git-format-patch[]
 618ifndef::git-log[]
 619--exit-code::
 620        Make the program exit with codes similar to diff(1).
 621        That is, it exits with 1 if there were differences and
 622        0 means no differences.
 623
 624--quiet::
 625        Disable all output of the program. Implies `--exit-code`.
 626endif::git-log[]
 627endif::git-format-patch[]
 628
 629--ext-diff::
 630        Allow an external diff helper to be executed. If you set an
 631        external diff driver with linkgit:gitattributes[5], you need
 632        to use this option with linkgit:git-log[1] and friends.
 633
 634--no-ext-diff::
 635        Disallow external diff drivers.
 636
 637--textconv::
 638--no-textconv::
 639        Allow (or disallow) external text conversion filters to be run
 640        when comparing binary files. See linkgit:gitattributes[5] for
 641        details. Because textconv filters are typically a one-way
 642        conversion, the resulting diff is suitable for human
 643        consumption, but cannot be applied. For this reason, textconv
 644        filters are enabled by default only for linkgit:git-diff[1] and
 645        linkgit:git-log[1], but not for linkgit:git-format-patch[1] or
 646        diff plumbing commands.
 647
 648--ignore-submodules[=<when>]::
 649        Ignore changes to submodules in the diff generation. <when> can be
 650        either "none", "untracked", "dirty" or "all", which is the default.
 651        Using "none" will consider the submodule modified when it either contains
 652        untracked or modified files or its HEAD differs from the commit recorded
 653        in the superproject and can be used to override any settings of the
 654        'ignore' option in linkgit:git-config[1] or linkgit:gitmodules[5]. When
 655        "untracked" is used submodules are not considered dirty when they only
 656        contain untracked content (but they are still scanned for modified
 657        content). Using "dirty" ignores all changes to the work tree of submodules,
 658        only changes to the commits stored in the superproject are shown (this was
 659        the behavior until 1.7.0). Using "all" hides all changes to submodules.
 660
 661--src-prefix=<prefix>::
 662        Show the given source prefix instead of "a/".
 663
 664--dst-prefix=<prefix>::
 665        Show the given destination prefix instead of "b/".
 666
 667--no-prefix::
 668        Do not show any source or destination prefix.
 669
 670--line-prefix=<prefix>::
 671        Prepend an additional prefix to every line of output.
 672
 673--ita-invisible-in-index::
 674        By default entries added by "git add -N" appear as an existing
 675        empty file in "git diff" and a new file in "git diff --cached".
 676        This option makes the entry appear as a new file in "git diff"
 677        and non-existent in "git diff --cached". This option could be
 678        reverted with `--ita-visible-in-index`. Both options are
 679        experimental and could be removed in future.
 680
 681For more detailed explanation on these common options, see also
 682linkgit:gitdiffcore[7].