hg diff [OPTION]... ([-c REV] | [-r REV1 [-r REV2]]) [FILE]...

diff repository (or selected files)

    Show differences between revisions for the specified files.

    Differences between files are shown using the unified diff format.

    Note:
       diff may generate unexpected results for merges, as it will default to
       comparing against the working directory's first parent changeset if no
       revisions are specified.

    When two revision arguments are given, then changes are shown between
    those revisions. If only one revision is specified then that revision is
    compared to the working directory, and, when no revisions are specified,
    the working directory files are compared to its parent.

    Alternatively you can specify -c/--change with a revision to see the
    changes in that changeset relative to its first parent.

    Without the -a/--text option, diff will avoid generating diffs of files it
    detects as binary. With -a, diff will generate a diff anyway, probably
    with undesirable results.

    Use the -g/--git option to generate diffs in the git extended diff format.
    For more information, read "hg help diffs".

    Returns 0 on success.

options:

 -r --rev REV [+]         revision
 -c --change REV          change made by revision
 -a --text                treat all files as text
 -g --git                 use git extended diff format
    --nodates             omit dates from diff headers
 -p --show-function       show which function each change is in
    --reverse             produce a diff that undoes the changes
 -w --ignore-all-space    ignore white space when comparing lines
 -b --ignore-space-change ignore changes in the amount of white space
 -B --ignore-blank-lines  ignore changes whose lines are all blank
 -U --unified NUM         number of lines of context to show
    --stat                output diffstat-style summary of changes
 -I --include PATTERN [+] include names matching the given patterns
 -X --exclude PATTERN [+] exclude names matching the given patterns
 -S --subrepos            recurse into subrepositories

[+] marked option can be specified multiple times

use "hg -v help diff" to show more info