Basic UNIX Commands
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Note: Whatever is in parentheses in the table below are examples

COMMAND FORMAT DESCRIPTION
man man [command] Provides information on a specific command.
e.g.: man man (Provides information on the man command.)
man cp (Provides information on the cp command.)
ls ls Lists the contents, such as the files and subdirectories, in a directory.
e.g.: ls (Lists all files and subdirectories in the current directory.)
ls -l (Lists all files and subdirectories in the current directory in the long format, giving information about mode, number of links, owner, group, size in bytes, and time of last modification.)
pwd pwd Displays the current working directory.
e.g.: pwd (Displays the current working directory the user is in.)
mkdir mkdir [directory or path] Creates a directory.
e.g.: mkdir mydirectory (Creates a directory called mydirectory below the current directory.)
cd cd [directory or path] Changes the current working directory.
e.g.: cd newdirectory (Moves to the directory newdirectory which is below the current directory.)
cd /mydir1/mydir2 (Moves to the directory mydir2 which is below the directory mydir1 which in turn is under the current directory.)
cd (Moves to the home directory; the directory where the user is placed when he/she logs in.)
cat cat filename Lists the contents of the file called filename.
e.g.: cat myfile (Lists the contents of myfile.)
pr pr filename Lists the contents of the file called filename in a formatted fashion - page headers and numbers.
e.g.: pr myfile (Lists the contents of myfile in a formatted fashion - page headers and numbers.)
lpr lpr filename Prints a file, called filename, on the line printer.
e.g.: lpr myfile (Prints myfile on the line printer.)
rm rm filename Deletes a file called filename.
e.g.: rm example.file (Deletes the file called example.file.)
rmdir rmdir directoryname Deletes a directory called directoryname.
e.g.: rmdir sample.dir (Deletes the directory called sample.dir.)
cp cp filename1 filename2 Copies the contents of a file to another file.
e.g.: cp example sample (Copies the contents of the file example to sample.)
mv mv oldfile newfile Renames a file; moves the contents of the old file to the new file.
e.g.: mv myfile1 myfile2 (Changes the name of the file from myfile1 to myfile2.)
mv olddirectory newdirectory Renames a directory; moves the contents of the old directory to the new directory.
e.g.: mv mydir1 mydir2 (Changes the name of the directory from mydir1 to mydir2.)
pine pine Invokes screen oriented mail program.
elm elm Invokes screen oriented mail program.
date date Displays the current date and time.
ps ps Shows the status of the job processes in the system.
passwd passwd Changes your password.
kill kill PID Terminates a job process which is represented by a Process IDentification (PID) number.
e.g.: kill 46 (Kills or aborts job process 46.)
who who Lists all the users who are currently using the system.
logout logout Leaves the system that you are in.
CTRL-s CTRL-s Pauses the display of information on the terminal screen. (Hold down the CTRL key and press the s key.)
CTRL-q CTRL-q Resumes the display of information on the terminal screen. (Hold down the CTRL key and press the q key.)
CTRL-c CTRL-c Aborts the execution of the current command. (Hold down the CTRL key and press the c key.)

Metacharacters

Metacharacters are certain characters that have a special meaning in Unix.

CHARACTER DESCRIPTION EXAMPLE
* Matches all or any string of characters ls *
? Matches any single character ls chart?
& Places the command as a task in the background process grep word myfile&
; Allows multiple commands to be issued on a single line cd;pwd;ls -al
\ Turns off the special meaning of a metacharacter grep \* trial
< Redirects the input of a command from a file mail boss < report
> Redirects the output of a command into a file spell memo > misspell
| Directs the output from one command to be the input of the next command pr myfile | lpr