Basic UNIX Commands

UNIX

Connecting:

{ } passwd:xxxxxxx
login:
username.

passwd:
password.

logout
Used to exit system.

passwd
Used to change your password.

File Manipulations

items in [] are optional

items in {} can be repeated 0 or more times.

fn = filename (possible with wildcards)

dir = directory name

{ } lpr -Psite fnxxxx
cat fn {fn}
concatenate, can be used to display a file.

more fn {fn}
displays file(s) one screenful, at a time. At MORE prompt enter: space bar - for next screenful <cr> - for next line, q - to quit more command.

cp fn1 fn2
copy file - fn1 to fn2, fn1 remains.

mv fn1 fn2
move (rename) file - fn1 to fn2, fn1 no longer exists.

rm fn
remove (delete) file.

lpr -Psite fn
print a file, site = laserXXX, where XXX is the room number.

lpr -s -Psite fn
print a file without copying it to the printer's spool directory. Use this command to print large files. It must be run from the print server.

ls [fn]
list files in current directory option filename is usually used to display files matching wildcards. (ie. ls *.s will list all assembly language source files.)

ls -lgRa
Recursive listing of all files within all subdirectories. Longest, most descriptive format.

cd [dir]
change working directory, ``home directory" if not specified. cd .. will backup one level in the directory structure.

pwd
print working directory path.

mkdir dir
make a new directory, giving it the name dir (within the current directory)

rmdir dir
remove (delete) the directory named dir (the directory must be empty)
file fn
Tries to determine what kind of information is in a file by consulting the file system index and by reading the file itself.

du
Prints a summary of total space occupied by all files in a hierarchy.

sort fn
Sorts ASCII files line-by-line.

chmod
Change file permissions. See the man pages for a complete description of settings. Use this command to determine whether files can be readable by other people.

gzip fn
Use this to compress files not needed immediately to conserve disk space. A ``.gz" will be appended to the filename.

gzip -d
Uncompresses files with ``.Z" at end of filename.

head {-n} fn
Prints first n lines of a text file. If no number is specified, the default is 10.

tail {-n} fn
Prints last n lines of a text file. If no number is specified, the default is 10.

Communication:

{ } write usernamex
finger
list users currently on the system.

who
list users currently on the system.

w
what, similar to who but includes what they are doing.

mail
Email message utility.

mail username
will send Email to username.

elm
Email message utility.

talk username
allows two users to have an interactive conversation over the computer.

write username
allows a user to put a message on another users screen.

mesg n
Makes it so other users cannot interrupt you with talk requests, and write messages.

Redirection:

{ } cmd < fn1 > fn2xx
cmd < fn1 > fn2
Run the program cmd using fn1 for the input file (normally the keyboard, but this gives the user the ability to send input from a file instead of the keyboard) and fn2 for the output file (normal the terminal screen). Bot

h < and > are optional. Use >! to overwrite an existing output file.

Help:

{ } man -k keywordxx
man command
manual, returns the manual for the given command from the UNIX on-line manual. If you cannot find a man page for a command, there may be one in a directory that isn't in your MANPATH. Your MANPATH is setup in the .login file and a command's man page is usually in a man directory off the same parent directory as the command. For example, if the command is located in /usr/local/bin, its man page is probably in /usr/local/man.

man -k keyword
display manual headings containing the word keyword.

Miscellaneous:

{ } kill %jobnumberxx
alias name def
Assigns ``def'' to the alias ``name''. Usually found in the .cshrc file. For example ``alias dir ls -la''.
clear
Clears screen.

h
List history of last 15 commands used.

!!
re-execute the last command entered.

!x
re-execute the last command that started with the given letter, eg !c will re-execute the last command that began with the letter c.

jobs -l
list all currently stopped or background jobs with job numbers and process ID's.

kill %jobnumber
kill ID
kill the given job number or process ID. (you might need to kill a job to logout if you have accidentally put a job into the background or stopped a job)

<control>C
kill the current process - the one in the foreground

<control>Z
suspend foreground process.

bg
put a suspended job in the background.

fg
put a suspended or background job in the foreground.

date
display time and date.