Unless you have a Unix machine sitting on your desktop, you're probably accessing it through telnet or a command-line shell. This interface may be a little intimidating to new users who are usually a tad more comfortable with a point-and-click interface. But it's really not as hard as it looks.
This reference sheet gives you the basic commands you'll need, focusing especially on file management. You can also learn how to combine commands and become a real power user. If you need more help getting started, take a look at Pam's excellent introduction entitled Learn Enough Unix for Your Resume. Between that article and this guide, you'll be on your way to becoming a Unix master. Soon you'll be wondering how you got along without it.
cat
Prints files to input, or reads and returns input.
cd
Changes directories, allows movement through the directory structure.
chmod
Changes permissions on a file or directory
chown
Changes ownership of files and directories
cp
Copies files.
date
Displays or sets the current date and time.
diff
Shows differences between files.
exit
Ends a process, and returns to the parent process.
find
Searches for files.
finger
Looks up user information.
grep
Look for lines which match a given string or regular expression.
head
Prints the first few lines of a file.
kill
Terminates a process by PID.
less
Displays the content of a file.
lprm
Removes printer queue requests.
ls
Lists files in a directory.
man
Displays the manual page for a program.
mkdir
Creates directories.
more
Prints the contents of files.
mv
Moves or renames files.
passwd
Creates or changes passwords.
ps
Gives a list of all active processes, along with other information.
pwd
Prints the current directory.
rlogin
Logs into remote systems
rm
Removes files.
rmdir
Removes empty directories.
su
Logs in as another user.
tail
Prints the last few lines of a file.
telnet
Communicates with other hosts via the telnet protocol.
who
Gives a list of logged in users.
