Ctrl-D            allows you to leave the computer properly.
cp                  allows you to copy files
echo $shell        displays the shell that you are currently runing
exist              ends a shell you have started
hostmane   displays the name of the host computer that you are logged onto
login             allows you to log onto the computer with a valid usename/password pair
ls                  allows you to display names of files and directories
man             allows you view a manual page for a comand of topic
mv                allows you to move or rename files
passwd       allows you to change you password on the computer
set                allows you to see and change the enviroment variables in sh,bash or ksh
setenv          allows you to see and change the enviroment variables in csh
telnet            allowss you to log on to a computer on a network ot the internet
uname         displays information about the operating system running the computer.
whatis          allows you to view a brief description of a command
whereis        display the path(s) to commands and utilities in certain key directories.
whoami        displays your usename