inst
        another parent, use::

            brz diff -r<chosen_parent>..X

        The changes between the current revision and the previous revision
        (equivalent to -c-1 and -r-2..-1)

            brz diff -r-2..

        Show just the differences for file NEWS::

            brz diff NEWS

        Show the differences in working tree xxx for file NEWS::

            brz diff xxx/NEWS

        Show the differences from branch xxx to this working tree:

            brz diff --old xxx

        Show the differences between two branches for file NEWS::

            brz diff --old xxx --new yyy NEWS

        Same as 'brz diff' but prefix paths with old/ and new/::

            brz diff --prefix old/:new/

        Show the differences using a custom diff program with options::

            brz diff --using /usr/bin/diff --diff-options -wu
    r 