rcs [options] files
An administrative command for setting up or changing the default attributes of RCS files. Among other things, rcs lets you set strict locking (-L), delete revisions (-o), and override locks set by co (-l and -u). RCS files have an access list (created via -a); anyone whose username is on the list can run rcs. The access list is often empty, meaning that rcs is available to everyone. In addition, you can always invoke rcs if you own the file, if you’re a privileged user, or if you run rcs with -i. rcs accepts the standard options -q, -V, -x, and -z.
Append the comma-separated list of users to the access list.
Append otherfile’s access list to the access list of files.
Set the default branch to R or, if R is omitted, to the highest branch on the trunk.
Set the comment character to string str. This option is obsolete, because RCS normally uses the preceding $Log$ line’s prefix when inserting log lines during checkout.
Erase everyone (or only the specified users) from the access list.
Create (initialize) an RCS file, but don’t deposit a revision.
Interactive mode; prompt user even when standard input is not a terminal. (New in RCS Version 5.)
Use c as the default style for keyword substitution. (See co for values of c.) -kkv restores the default substitution style.
Lock revision R or the latest revision. -l “retroactively locks” a file and is useful if you checked out a file incorrectly ...