From the Unix manual:
CVS(1)
NAME
cvs - Concurrent Versions System
SYNOPSIS
cvs [ cvs_options ]
cvs_command [ command_options ] [ command_args ]
NOTE
This manpage is a summary of some of the features of cvs
but for more in-depth documentation, consult the Ced
erqvist manual (as described in the SEE ALSO section of
this manpage).
DESCRIPTION
CVS is a version control system, which allows you to keep
old versions of files (usually source code), keep a log of
who, when, and why changes occurred, etc., like RCS or
SCCS. Unlike the simpler systems, CVS does not just oper
ate on one file at a time or one directory at a time, but
operates on hierarchical collections of directories con
sisting of version controlled files. CVS helps to manage
releases and to control the concurrent editing of source
files among multiple authors. CVS allows triggers to
enable/log/control various operations and works well over
a wide area network.