Managing Sessions

login - prompts the user for username and password.
nohup - Prevents programs from getting killed on logout.
rlogin - enables you to establish a user session on another computer connected to the LAN. Deprecated, safety-hazard. Use ssh instead.
screen - Terminal multiplexer. This is somewhat like a virtual terminal, only much more powerful.
shutdown - Shuts down the system.
startx - This shell script, enables you to start a X session.
tty - Displays the number of the terminal device that is currently in use.
xdm, kdm, gdm - Starting the X (KDE, Gnome) Display Manager
xterm - Starts the xterm terminal emulation program. requires the X window system.

Managing sessions