2518     By default, grep searches the expression on the working directory.

  2518     By default, grep prints the most recent revision number for each

  2519     To search history and show the most recent revision number for each

  2519     file in which it finds a match. To get it to print every revision

  2520     file in which it finds a match, use :hg:`grep -r tip:0`.

  2520     that contains a change in match status ("-" for a match that becomes

  2521     To get it to print every revision that contains a change in match status

  2521     a non-match, or "+" for a non-match that becomes a match), use the

  2522     ("-" for a match that becomes a non-match, or "+" for a non-match that

  2522     --diff flag.

  2523     becomes a match), use the --diff flag.