A.15 rdiff—'patch' format diffs between releases

• rdiff [-flags] [-V vn] [-r t|-D d [-r t2|-D d2]] modules…
• Requires: repository.
• Changes: nothing.
• Synonym: patch

Builds a Larry Wall format patch(1) file between two releases, that can be fed directly into the patch program to bring an old release up-to-date with the new release. (This is one of the few CVS commands that operates directly from the repository, and doesn't require a prior checkout.) The diff output is sent to the standard output device.

You can specify (using the standard `-r' and `-D' options) any combination of one or two revisions or dates. If only one revision or date is specified, the patch file reflects differences between that revision or date and the current head revisions in the RCS file.

Note that if the software release affected is contained in more than one directory, then it may be necessary to specify the `-p' option to the patch command when patching the old sources, so that patch is able to find the files that are located in other directories.