arx sub-commands
                        ----------------

* Basic Commands

   add               Add an inventory id for a path
   browse            Print an outline of the what is in an archive
   commit            Store the current project tree in the archive
   diff              Compare a project tree against a pristine revision
   get               get a revision from an archive, making a project tree
   init              Initialize the current tree
   log               Print out revision logs
   make-archive      Create and register an archive
   mv                Rename a path and its inventory id.
   param             print or change an ArX parameter
   rm                Delete a path and its inventory id.
   tree-lint         Audit a source tree for problems

* Branching and Merging Commands

   fork              Create a project tree for a new branch
   merge             Merge a project tree with a sibling branch
   missing           Show which patches are missing from a project tree
   replay            Update a project tree by replaying individual patches
   tag               Create a symbolic name for a revision or group of revisions

* Miscellaneous Advanced Commands

   archives          Query, add, or delete archive registrations
   edit              Make a path editable
   export            Create a project tree without ArX control files
   file-diff         Print the changes to a file
   file-orig         Print the original version of a file
   file-undo         Undo the changes to a file
   history           Query, add or delete the patches in a project tree
   ignore            print or change the ignore regexp for a project tree
   inventory         Print out an inventory of a project tree
   library           Manipulate cached revisions in a revision library
   property          Set or unset a property for a path
   redo              Redo changes in a working directory
   undo              Temporarily undo changes to a project tree

* Advanced Patch Commands

   dopatch           Apply a patch to a source tree
   get-patch         Retrieve a patch from an archive
   mkpatch           Create a patch between two source trees
   patch-report      Print out a nicely formatted description of a patch

* Administrative Commands

   archive-cache     Query, add or delete cached revisions in an archive
   break-lock        Break a branch lock
   delete-branch     IRREVOCABLY delete a branch within an archive
   delete-revision   IRREVOCABLY delete a revision within an archive
   mirror            mirror one archive to another
   sig               Manage cryptographic signatures
   tree-branch       print or set the default branch for a source tree
   tree-cache        Manipulate cached revisions in the project tree
   tree-root         Print the root of a project tree
   update-listing    update the .listing files in an archive