UNIX Command

 

Command		Description (short)	Example	Explanation
date		Writes the current date to the screen	date	Mon Nov 20 18:25:37 EST 2000
sort infile		Sorts the contents of the input file in alphabetical order	sort names	Sorts the contents of names in alphabetical order
who		Tells you who is logged onto your server	who	None
	who am I	Tells you your user information	who am i whoami	None
	clear	Clears the window and the line buffer	clear	None
	echo whatever I type	Writes whatever I type to the screen.	echo hey you!	Writes hey you! to the screen
banner big words		Does the same thing as echo only in BIG words	banner hey!	Writes hey! in large letters on the screen
cat file1 file2 file3		Shows the three files in consecutive order as one document (can be used to combine files)	cat cheese milk	This prints the cheese file to the screen first and immediately follows it with the milk file.
cat file1> file2 cat file1>> file2		Replaces the contents of file2 with that of file1. If file2 is not present, it creates file2 with the contents of file1. Appends the contents of file1 to the end of file2
df system		Reports the number of free disk blocks	df ~ df $HOME	Both commands will print the total kb space, kb used, kb available, and %used on the home system (your system).
head file		Prints the first 10 lines of the file to the screen	head addresses	Prints the first 10 lines of addresses to the screen
		Number of lines can be modified	head -25 addresses	Prints the first 25 lines of addresses to the screen
tail file		Prints the last 10 lines of the file to the screen	tail test.txt	Prints the last 10 lines of test.txt to the screen
		Number of lines can be modified here, too	tail -32 test.txt	Prints the last 32 lines of test.txt to the screen
more input		This prints to screen whatever is input—useful because it only shows one screen at a time.	more groceries	This will list the groceries file to the screen.
		scroll bar continues to the next screen
		return moves one line forward
		Q quits
		G goes to the end
		1G goes to the beginning
		Ctrl u moves up ½  screen
		Ctrl d moves down ½ screen

Command		Description (short)			Example	Explanation
ls   (-option-optional)		Lists all the nonhidden files and directories			ls	Lists all nonhidden files and directories in the current directory
					ls bin	Lists all nonhidden files and directories in the bin directory
ls -l     or      ll		Lists all nonhidden files and directories in long format			ls -l ll	Lists all nonhidden files and directories in the current directory in long format
					ls -l work ll work	Lists all nonhidden files and directories in the work directory in long format
ls -a		Lists all files and directories including hidden ones			ls -a	Lists all files and directories, including hidden, in the current directory
					ls -a temp	Lists all files and directories in the temp directory.
ls -r		Lists all files and directories in reverse alphabetical order			ls -r	Lists all nonhidden files and directories in the current directory in reverse alphabetical order
Ls -ltr		Long listing, then based on time, then reverse of the current output(ie reverse of  that would have displayed in ls –lt)			ls -r abc	Lists all nonhidden files and directories in the abc directory in reverse alphabetical order
ls -t		Lists all nonhidden files in the order they were last modified(newest first)			ls -t	Lists all the nonhidden files in the current directory in the order they were last modified from most recent to last
					ls -t work	Lists all the nonhidden files in the work directory in the order they were last modified from most recent to last
NOTE: Options can be combined using ls					ls -al	Lists all files (including hidden (-a)) in long format (-l)
Important Characters | >  >>  & ~ <			“pipe” directs the output of the first command to the input of another. Sends the output of a command to a designated file Appends the output of a command to a designated file Runs command in the background; you can still work in the window Designates the home directory ($HOME) Designates input from somewhere other than terminal	ls -l | more ls -l > myfiles ls -l >> allfiles xclock & echo ~ progA < input1		Lists your files in long format one screen at a time Prints your listing to a file named myfiles Appends your filenames to the end of the allfiles file Runs xclock (a clock) allowing you to keep working Writes your home directory to the screen progA program gets its input from a file named input1
	Wildcards * ? [  ]	UNIX has a set of wildcards that it accepts. Any string of characters Any one character Match any character in the brackets (a hyphen is used for ranges of characters)			ls *.c ls file? ls v[6-9]file	Lists any file or directory (nonhidden) ending with c Lists any file/directory with file and 1 character at the end Lists v6file, v7file, v8file, and v9file

Command	Description (short)			Example		Explanation
cd directory	Changes your current directory to the directory specified			cd bin		Changes directory to the bin directory
				cd .. cd ../..	Moves you to the directory that contains the directory you are currently in Ex. Current directory=/home/users/bob/bin execute cd .. New directory= /home/users/bob or  executing cd ../.. New directory= /home/users.
				cd -		Moves you to the directory you just came from
				cd ~ cd		Both move you to your home directory (the directory you start from initially)
mkdir dirname	Creates a directory			mkdir junk		Makes a directory named junk in your current directory
	You can also designate where the directory is to reside.			mkdir ~/left		Makes a directory in your home directory named left
rm file1 file2 file3	Removes (deletes) file(s)			rm xyz		Deletes a file named xyz
				rm xyz abc		Deletes the files named xyz and abc
				rm *		Deletes everything nonhidden
rm -i file1 file2	Prompts before deletion of files *******USE -i AT FIRST*******			rm -i *		Prompts at each nonhidden file and lets you decide whether or not to delete it
rm -f file1 file2	Forces deletion without prompt regardless of permissions			rm -f program		Removes the file program without regard to permissions, status, etc.
rm -r directory rm -R directory	Remove a directory along with anything inside of it			rm -r bin rm -R bin		Each of these will remove the bin directory and everything inside of it.
rmdir directory	Removes a directory like rm -r does if the directory is empty			rmdir bin		Removes the bin directory if it is empty
****dangerous**** rm -fR name rm -Rf name		This combination will force the removal of any file and any directory including anything inside of it		rm -Rf c_ya		Forces removal without prompts of the c_ya directory and anything inside of it
rm -Ri directory	Deletes the contents of a directory and the directory if it is empty by prompting the user before each deletion			rm -Ri rusure		Deletes anything in the directory called rusure that you verify at the prompt, and if you remove everything in the directory, you will be prompted whether you want to remove the directory itself or not
NOTE: Options can be combined using rm
rmdir -p directory	Removes a directory and any empty parent directories above it (-pi does the same thing but it prompts before each removal)		rmdir -p /home/bin/dir1			Deletes the dir1 directory; if bin directory is empty, it is deleted, and if home directory is empty it is also deleted

Command	Description (short)	Example	Explanation
cp file1 newname	Copies a file (file1) and names the copy the new name (newname)	cp old new	Makes a copy of the file/directory named old and names the copy new, all within the current directory NOTE: If you copy a file to a newfile name and newfile already exists, the newfile contents will be overwritten.
		cp file dir2/	Places a copy of file in dir2/ and it retains its original name
		cp ../dir1/* .	Copies everything from the dir1 directory located just below where you currently are and places the copy “here” ( . ) in your current directory
cp -p name target	Preserves all permissions in the original to the target	cp -p execut1 execut2	Copies execut1 executable file and calls the copy execut2, which also has executable permissions
cp -R directory target	Copies a directory and names the copy the new name (target)	cp -R old/ junk/	Makes a copy of the directory named old and names the directory copy junk
cp -f name target	Forces existing pathnames to be destroyed before copying the file	none	No example or description needed
mv initial final	Renames files and directories	mv temp script_1	Renames the file (or directory) temp to the name script_1 in the current directory
	Also moves files to other directories	mv script.exe ~/bin	Moves the script.exe file to the bin directory that is in the home (~) parent directory and it keeps its initial name
	You can do multiple moves.	mv script_1 script.exe ~/bin	Moves both script_1 and script.exe to the bin directory
pwd	Prints the current directory to the screen	pwd	May print something like “/home/bob”
pr (option) filename	Prints the specified file to the default printer (options are not required but can be combined in any order)	pr userlist	Prints the contents of userlist to the default printer
pr +k filename	Starts printing with page k	pr +5 userlist	Prints the contents of userlist starting with page 5
pr -k filename	Prints in k columns	pr -2 userlist	Prints the contents of userlist in 2 columns
pr -a filename	Prints in multicolumns across the page (use with -k)	pr -3a userlist1	Prints userlist in three columns across the page
pr -d filename	Prints in double space format	pr -d userlist	Prints userlist with double space format
pr  -h “header” filename	Prints the file with a specified header rather than the filename	pr -h “users” userlist	Prints userlist with users as the header
NOTE: Options can be combined using pr

Command	Description (short)				Example	Explanation
lpconfig printer_id queue			Configures remote printers to a local print queue	lpconfig prntr1 bobprt			Configures a printer named prntr1 to accept print requests from a local queue named bobprt
lpconfig -r queue	Removes the said queue from the local system				lpconfig -r bobprt	Removes bobprt queue from the local system if the person removing the queue is the owner or “root”
lpconfig -d queue	Makes the said queue the default queue				lpconfig -d vpprnt	Makes vpprnt the default print queue
lpstat (-options)	Prints printer status information to screen (options not required)				lpstat	Prints status of all requests made to the default printer by the current server
lpstat -u“user1, user2”		Prints the status of requests made by the specified users			lpstat -u“bob”	Prints status of all requests made by the user with the id bob
lpstat s	Prints the queues and the printers they print to				none	None
lpstat -t	Shows all print status information				none	None
lpstat -d	Shows the default printer for the lp command				none	None
lpstat -r	Lets you know if the line printer scheduler is running				none	None
lp (-option) file(s)	Like pr, this prints designated files on the connected printer(s) (options not required and options may be combined).				lp junkfile	Prints the file junkfile to the default printer in default one-sided, single-sided, single-spaced format
lp -ddest file(s)	Prints the file(s) to a specific destination				lp -dbobsq zoom	Sends the file zoom to the bobsq print queue to print
lp -nnumber file(s)	Allows user to designate the number of copies to be printed				lp -n5 crash	Prints five copies of crash in default settings
lp -ttitle file(s)	Places title on the banner page				lp -tBobs cash	Prints Bobs on the banner page of the file printout named cash
lp -ooption file(s)	Allows printer-specific options to be used (i.e., double-sided or two pages per side, etc.)				lp -od output	Prints the output file double-sided on the printout
					lp -obold output	Prints output in bold print
					lp -ohalf output	Divides the paper into two halves for printing output
					lp -oquarter output	Prints four pages of output per side of paper
					lp -olandscape output	Prints output in landscape orientation
					lp -oportrait output	Prints output in portrait orientation
NOTE: Options can be combined using lp
cancel request_id	Stops print jobs or removes them from the queue (request_ids are obtained using lpstat)				cancel 5438	Stops the print job with the id 5438 whether it is printing or if it is sitting in the queue
cancel -a printer	Removes all print requests from the current user on the specified printer				cancel -a bobsprt	Removes all the requests from the current user to the printer named bobsprt
cancel -u login_id	Removes any print requests queued belonging to the user				cancel -u bob	Cancels all queued print requests for user bob

Command	Description (short)		Example	Explanation
ps	Shows certain information about active processes associated with the current terminal		ps	Shows a listing of process IDs, terminal identifier, cumulative execution time, and command name
ps -e	Shows information about all processes		ps -e	Shows a listing of process IDs, terminal identifiers, cumulative execution time, and command names for all processes
ps -f	Shows a full listing of information about the processes listed		ps -f	Shows UID (user or owner of the process), PID (process ID--use this number to kill it), PPID (process ID of the parent source), C (processor utilization for scheduling), STIME (start time of the process), TTY (controlling terminal for the process), TIME (cumulative time the process has run), and COMMAND (the command that started the process)
ps -u user_id	Shows all processes that are owned by the person with the pertinent user_id		ps -u bob	Shows all the processes that belong to the person with the userid bob
ps -ef	Shows all processes in a full listing		ps -ef	Shows all current processes in full listing
kill process_id	Stops the process with the said id		kill 6969	Kills the process with PID 6969
kill -9 process_id	Destroys the process with the said id		kill -9 6969	PID # 6969 doesn’t have a chance here.
grep string file	Searches input file(s) for specified string and prints the line with matches		grep mike letter	Searches for the string mike in the file named letter and prints any line with mike in it to the screen
grep -c string file	Searches and prints only the number of matches to the screen		grep -c hayes bankletter	Searches the file bankletter for the string hayes and prints the number of matches to the screen
grep -i string file	Searches without regard to letter case		grep -i hi file1	Searches file1 for hi, Hi, hI, and HI and prints all matches to the screen
grep -n string file	Prints to the screen preceded by the line number		grep -n abc alpha	Searches alpha for abc and prints the matches’ lines and line numbers to the screen
grep -v string file	All lines that do not match are printed		grep -v lead pencils	Prints all lines in pencils that do not contain the string lead
grep -x string file	Only exact matches are printed		grep -x time meetings	Prints only lines in meetings that match time exactly
	grep is useful when you use it in a | “pipe”		ps -ef | grep bob	Finds all processes in full listing and then prints only the ones that match the string bob to the screen
	You can also redirect its output to a file.	grep -i jan b_days>mymonth		Searches the file b_days for case-insensitive matches to jan and places the matching lines into a file called mymonth

Command	Description (short)	Example	Explanation
vuepad filename	Opens filename for editing/viewing in the vuepad editor	none	None
vi filename	Text editor that exists on every UNIX system in the world	none	None
emacs filename	Another text editor	none	None
compress filename	Compresses the file to save disk space.	none	None
uncompress filename	Expands a compressed file	none	None
awk	UNIX programming language	none	None
eval `resize`	Tells the target computer that you’ve resized the window during telnet	none	None
chexp # filename	Keeps the file(s) from expiring (being erased) on the target computer for # days	chexp 365 nr*	Keeps the target computer from deleting all files starting with nr for 1 year (365 days)
		chexp 4095 nr*	Makes all files whose name starts with nr never expire or be deleted (infinite)
qstat	Displays the status of a process that has been submitted the Network Queuing System (basically a batch job)	qstat	Shows the status of the requests submitted by the invoker of the command—this will print request-name, request-id, the owner, relative request priority, and request state (is it running yet?)
		qstat -a	Shows all requests
		qstat -l	Shows requests in long format
		qstat -m	Shows requests in medium-length format
		qstat -u bob	Shows only requests belonging to the user bob
		qstat -x	Queue header is shown in an extended format
xterm xterm -option xterm +option	Opens a new window (x-terminal) for you to work -option sets the option +option resets the option to default	xterm	This opens another window like the one you are currently working in. USING XTERM WILL ELIMINATE A LOT OF DESKTOP CLUTTER. I STRONGLY SUGGEST YOU LEARN TO USE IT IN YOUR SCRIPTS.
xterm -help	Displays the xterm options	xterm -help	Shows the options available

Command	Description (short)		Example	(Explanation)
xterm -e program	Executes the listed program in the new xterm window—when the program is finished, the new xterm window goes away		xterm -e myprog.exe	This opens an xterm window and executes the program myprog.exe from that window so that you may still work in your present window.
xterm -sb	Opens an xterm that saves a set number of lines when they go off the top of the page and makes them accessible with a scroll bar		xterm -sb	Puts a scroll bar on the right side of the page for reviewing past lines in the window NOTE: When clicking in the scroll bar, the left button scrolls down, the right scrolls up, and the middle snaps the scroll bar to the mouse position for dragging up and down.
xterm -sl number	Specifies the number of lines to be saved once they go off the top of the screen (default is 64)		xterm -sl 1000	The xterm will save 1,000 lines of work once it has moved off the immediate viewing area; it can be accessed using the scroll bar.
xterm -geom xxy+px+py		This option allows you to specify the size x pixels by y pixels and placement position x by position y of the new window when it opens. Position +0+0 is the top left-hand corner of the screen, and the bottom right is approx. +1200+1000 depending on your resolution. Note: The size of the window takes precedence over position, so if you position it too close to the side of the screen, it will position at the edge with the correct size.	xterm -geom 80x80+0+50 xterm -geom 10x35+300+500 xterm -geom 5x5+0+0	The first command will open a window 80 pixels wide by 80 pixels tall and position its top left-hand corner at 0 pixels to the right of the left edge and 50 pixels down from the top of the screen. The second command will open a window 10 pixs wide by 35 pixs tall and position its top left-hand corner 300 pixs from the left edge and 500 pixs down from the top. The third command will make a 5 by 5 window and position its top left-hand corner at the top left-hand corner of the screen. xterm will not compromise size when positioning.
xterm -title label	Allows you to label your window’s top title bar		xterm -title SCRIPTS	Opens an xterm window with the title SCRIPTS (default is whatever follows the -e option)
xterm -(areas) color	Allows you to modify different colors in your xterm window		xterm -bg white xterm -bd huntergreen xterm -fg red	The first command sets the background color to white. The second command sets the window border color to huntergreen. The third command window sets the text color to red.
xterm -fn font	Sets the font in the new xterm window		xterm -fn courr18	Sets the font to courr18 (default is fixed)
xterm -iconic	Starts the new xterm as an icon (double-click to maximize)		xterm -iconic -title xyz	Opens an xterm in iconic form with the title xyz
NOTE: Options can be combined using xterm