Useful UNIX operating system commands

passwd	change password	finger	show current users
man commandname	help for commandname	apropos keyword	find commands related to keyword
mkdir dirname	create directory	pwd	print (show) current directory
cd dirname	change directory to dirname	cd ..	go to parent directory (one level up)
ls	list files in current directory	mv oldname newname	change name oldname to newname
mv filename dirname	move file from current directory to new directory	cp oldname newname	copy content of file oldname to file newname
rm filename	remove file	cat filename	show contents of file
more filename	show content of file page by page	logout	log out

UNIX is case sensitive.
UNIX commands can be repeated by using the up and down arrow keys on the keyboard.
Completion of commands. Suppose you want to copy the file, filename. You could type cp filename. Instead, you can type cp fil and then hit the tab key. If there are no other files that also begin with "fil", the file name will be completed.
UNIX is a multiprocess and multiuser environment that allows you to run several jobs at once and have long jobs run in you absence.

^C (control C)	kill job that is running interactively	^Z	suspend job that is running interactively
fg	foreground (resume) job that has been suspended	bg	background job that has been suspended
jobs	list jobs (running and suspended)	top	list processes with the highest cpu usage

To run a command in the background append & to the end of the command.
To stop a job that is running in the background, enter the command ps. Browse through the list of jobs and note the PID number of the one you wish to stop. At the prompt type kill -9 PID#.

Summary of Emacs commands

To enter emacs and read file: type emacs < filename>

C- = control character
M- (meta) = Escape key pressed first

Useful commands

M-f	next word	M-b	previous word
C-a	beginning of line	C-e	end of line
C-k	delete line (starting from cursor)	C-d	delete next character after the cursor
C-y	restore (yank) line	C-x i	insert (file)
M-<	top of file	M->	bottom of file
C-v	next screen	M-v	previous screen
C-s	search	M-x	and then type "goto-line"
C-x C-s	save file	C-x C-c	quit emacs
C-z	suspend emacs (fg to restore)	C-x C-w	save file to different name

C-x i looks for a file in the same directory as the file you are editing. If sending mail, directory would be /tmp. If you want to insert a file from your home directory, delete '/tmp/' and type '~/filename'.

Links

Please send your additions and comments to Harvey Gould, hgould@clarku.edu.

Updated 6 January 2006.