login - is used when signing onto a system

login (with no argument) prompts for a user name and password (This also effectively logs you out)
login name may be used instead, although the password will still be requested

After a user logs in, the directory is set to /home/name/
(except for root login where the directory is set to /root/)

Login restrictions may be set for each user as follows:
time and date spans
tty console selections (i.e. Alt-F3 is tty3)
acceptable TCP/IP address ranges

see shutdown to bring the system down
see mail to send and receive mail