If you are working on a project and want to create a duplicate set of sources for some private testing or debugging, you can create a symbolic link to the SCCS subdirectory in your private working directory:
$ cd /private/working/cmd.dir $ ln -s /usr/src/cmd/SCCS SCCS
This enables you to retrieve a private (duplicate) set of working copies, of the source files using:
sccs get SCCS
While working in the duplicate directory, you can also check files in and out--just as you could if you were in the original directory.