[usr@svr dir]# cvs -d :pserver:cvsuser@cvs:/usr/local/cvsroot login
Logging in to :pserver:cvsuser@cvs:2401/usr/local/cvsroot
CVS password:

OR,

set export CVSROOT in .bash_profile in your root directory:

:pserver:cvsuser@cvsserver:/usr/local/cvsroot

Then

cvs login

cvs co ProjectName