Contacts a CVS server and confirms authentication information for a particular repository. This command does not affect either the working copy or the repository; it just confirms a password (for use with the :pserver: access method) with a repository and stores the password for later use in the .cvspass file in your home directory. Future commands accessing the same repository with the same username will not require you to rerun login, because the client-side CVS will just consult the .cvspass file for the password.
If you use this command, you should specify a repository using the pserver access method, like this
floss$ cvs -d :pserver:firstname.lastname@example.org:/usr/local/newrepos
or by setting the CVSROOT environment variable.
If the password changes on the server side, you have to rerun login.