[01] WHAT UNIX SHELLS ARE AVAILABLE HERE?

    A 'shell' is how you interact with the 'kernel'.  The kernel is the
    software that translates your commands into instructions that the
    hardware (machine) can understand.  The origin of the word 'shell'
    actually comes from MULTICS, which UNIX attempts to mimic.

    /bin/sh             Stephen Bourne's Shell
    /bin/csh            A shell with a C-like syntax
    /bin/ksh            David Korn's Shell  (default)
    /usr/pkg/bin/bash   GNU's Broken Again SHell
    /usr/pkg/bin/tcsh   BBN TENEX Shell .. Not quite like EXEC
    /usr/pkg/bin/rc     PLAN 9 'Run Commands' Shell
    /usr/pkg/bin/zsh    Paul Falstad's Shell

    The best thing to do is read up on the shell using the 'man'
    command.  You can run the shell by just executing it.  When
    you are sure you really want to change to that shell you:

    run the 'maint' command at shell to connect to 'ol.freeshell.org'
    and maintain/adjust password and shell settings.