Command	Purpose		Command	Purpose
pwd	Display current directory		chgrp	Change group ownership of a file/dir
cd	change current directory		useradd	Add a new user
ls	list directory contents		usermod	modify an existing user
cat	display contents of "file"		newgrp	change your current GID
more	display output one screen at a time		less	an alternative to 'more'
mkdir	create directory		man	lookup online documentation
rmdir	remove directory, if empty		info	another source of online documentation
touch	update timestamp of file		grep	print lines matching a pattern
cp	copy file		at	queue commands for later execution
mv	move file		gzip	compress or uncompress files
rm	delete file		diff	show differences between two files
uptime	Show load average, and last boot time		swapon	show or activate swap space
chmod	change permissions		mount	mount a file system
chown	change owner		umount	unmount a file system
w	show all users on system		ping	see if remote host is reachable
date	show system time and date		passwd	change password
whoami	show your username		vipw	manually edit password file
chfn	change your GECOS information		uniq	remove adjacent repeated lines
finger	display a users GECOS information		uname	show kernel revision
df	display free disk space		ps	display process listing
du	display disk usage by directory		fsck	filesystem checker