Document the -m flag to up.
=head1 SYNOPSIS
-B<up> [B<-v>] [B<-1>] [B<-f>] [B<-r>] [B<-x>]
+B<up> [B<-v>] [B<-1>] [B<-f>] [B<-r>] [B<-x>] [B<-m>]
<I<source directory>> <I<destination directory>>
=head1 DESCRIPTION
first (user) C<w> (write) mode bit is turned off on the version in the
destination directory.
+=item B<-m>
+
+Recognize and copy mount points rather than traversing the volumes they
+reference during the recursive copy operation. Without B<-m>, B<up>'s
+default behavior is to copy the contents of all volumes and subvolumes
+mounted under the source directory into the volume containing the
+destination directory.
+
=item B<-r>
Creates a backup copy of all files overwritten in the destination