Invoking a shell from TSO/E
To begin a z/OS UNIX shell session, you first log on to TSO/E and then invoke the TSO/E OMVS command. This starts a login shell, from which you can enter shell commands.
You can also login with rlogin or telnet.
See z/OS V2R2.0 UNIX System Services User's Guide for additional information on starting a shell session.