Unix Commands

Command/Syntax	What it will do
awk/nawk [options] file	scan for patterns in a file and process the results
cat [options] file	concatenate (list) a file
cd [directory]	change directory
chgrp [options] group file	change the group of the file
chmod [options] file	change file or directory access permissions
chown [options] owner file	change the ownership of a file; can only be done by the superuser
chsh (passwd -e/-s) username login_shell	change the user's login shell (often only by the superuser)
cmp [options] file1 file2	compare two files and list where differences occur (text or binary files)
compress [options] file	compress file and save it as file.Z
cp [options] file1 file2	copy file1 into file2; file2 shouldn't already exist.  This command creates or overwrites file2.
cut (options) [file(s)]	cut specified field(s)/character(s) from lines in file(s)
date [options]	report the current date and time
dd [if=infile] [of=outfile] [operand=value]	copy a file, converting between ASCII and EBCDIC or swapping byte order, as  specified
diff [options] file1 file2	compare the two files and display the differences (text files only)
df [options] [resource]	report the summary of disk blocks and inodes free and in use
du [options] [directory or file]	report amount of disk space in use
echo [text string]	echo the text string to stdout
ed or ex [options] file	Unix line editors
emacs [options] file	full-screen editor
exprarguments	evaluate the arguments. Used to do arithmetic, etc. in the shell.
file [options] file	classify the file type
find directory [options] [actions]	find files matching a type or pattern
finger [options] user[@hostname]	report information about users on local and remote machines
ftp [options] host	transfer file(s) using file transfer protocol
grep [options] 'search string' argument egrep [options] 'search string' argument fgrep [options] 'search string' argument	search the argument (in this case probably a file) for all occurrences of  the search string, and list them.
gzip [options] file gunzip [options] file zcat [options] file	compress or uncompress a file. Compressed files are stored with a .gz ending
head [-number] file	display the first 10 (or number of) lines of a file
hostname	display or set (super-user only) the name of the current machine
kill [options] [-SIGNAL] [pid#] [%job]	send a signal to the process with the process id number (pid#) or job  control number (%n). The default signal is to kill the process.
ln [options] source_file target	link the source_file to the target
lpq [options] lpstat[options]	show the status of print jobs
lpr [options] file lp[options] file	print to defined printer
lprm [options] cancel [options]	remove a print job from the print queue
ls [options] [directory or file]	list directory contents or file permissions
mail [options] [user] mailx [options] [user] Mail [options] [user]	simple email utility available on Unix systems. Type a period as the first character on a new line to send message out, question mark for help.
man [options] command	show the manual (man) page for a command
mkdir [options] directory	make a directory
more [options] file less [options] file pg [options] file	page through a text file
mv [options] file1 file2	move file1 into file2
od [options] file	octal dump a binary file, in octal, ASCII, hex, decimal, or character mode.
passwd [options]	set or change your password
paste [options] file	paste field(s) onto the lines in file
pr [options] file	filter the file and print it on the terminal
ps [options]	show status of active processes
pwd	print working (current) directory
rcp [options] hostname	remotely copy files from this machine to another machine
rlogin [options] hostname	login remotely to another machine
rm [options] file	remove (delete) a file or directory (-r recursively deletes the  directory and its contents) (-i prompts before removing files)
rmdir [options] directory	remove a directory
rsh [options] hostname	remote shell to run on another machine
scriptfile	saves everything that appears on the screen to file until exit is  executed
sed [options] file	stream editor for editing files from a script or from the command line
sort [options] file	sort the lines of the file according to the options chosen
sourcefile .file	read commands from the file and execute them in the current shell. source: C shell, .: Bourne shell.
strings [options] file	report any sequence of 4 or more printable characters ending in <NL> or <NULL>. Usually used to search binary files for ASCII strings.
stty [options]	set or display terminal control options
tail [options] file	display the last few lines (or parts) of a file
tar key[options] [file(s)]	tape archiver--refer to man pages for details on creating, listing, and  retrieving from archive files. Tar files can be stored on tape or disk.
tee [options] file	copy stdout to one or more files
telnet [host [port]]	communicate with another host using telnet protocol
touch [options] [date] file	create an empty file, or update the access time of an existing file
tr [options] string1 string2	translate the characters in string1 from stdin into those in string2 in  stdout
uncompressfile.Z	uncompress file.Z and save it as a file
uniq [options] file	remove repeated lines in a file
uudecode [file]	decode a uuencoded file, recreating the original file
uuencode [file] new_name	encode binary file to 7-bit ASCII, useful when sending via email, to be  decoded as new_name at destination
vi [options] file	visual, full-screen editor
wc [options] [file(s)]	display word (or character or line) count for file(s)
whereis [options] command	report the binary, source, and man page locations for the command named
whichcommand	reports the path to the command or the shell alias in use
who or w	report who is logged in and what processes are running
zcatfile.Z	concatenate (list) uncompressed file to screen, leaving file compressed on disk