It should be noted that this is just a quick reference guide to some of the more common utilities. This list is by no means all encompassing, nor inclusive. Descriptions of the utilities are brief. For detailed usage and information, use the man utility.
| . | The . command tells the shell to execute all the commands in the file that are given an argument. ie some_command |
| & | The & placed after a command tells the shell to run that command in the background. This allows you to keep using the shell for other commands while the background command is running, as opposed to waiting for the command to finish running in the foreground. |
| adduser | Used by the root or other admin with permission to create new user accounts. It is followed by the user name. ie adduser johndoe |
| alias | Used to make aliases or other names for commands. For example, we could make the ls command similar to the DOS version with dir.
alias dir=ls |
| apropos | A simple keyword search for the man pages. Used in the format apropos <argument>. |
| banner | Prints a large banner to standard output. If entered by itself, the user will be prompted for a single line of text. Can also be used as follows:
banner This is a line of text. |
| bg | Used to force a command running in the foreground to be put in the background. While the foreground command is being run you must press the CTRL and Z key, then type bg. |
| bind | bind is used to bind a command to a key or key sequence. Similar to keyboard shortcuts.
bind <key or key sequence> <command> |
| cat | lists the contents of a directory or file to standard output. |
| cd | changes the working directory. There are typically three different uses, as follows:
cd .. moves one directory up. cd moves to your home directory from any directory that you are currently in cd directory_name changes to that directory |
| chgrp | Used to change the group associated with the file permissions or diectory.
chgrp <new group> <file or directory> |
| chmod | Change permissions associated with a file or directory. See Unix Intermediate for detailed explanation. |
| chown | Used to change the ownership of a file or directory.
chown <new user id> <file> |
| chroot | Makes the root directory something other than / on the file system.
chroot <original location> <new location> |
| cp | Used to copy objects ( usually files ).
cp first_file second_file |
| dd | Used to convert file formats.
dd if=<filename> of -<location of file> |
| env | Used to list / view the environment variables. Used on its own without any argument. |
| fc | Used to edit the history file |
| fg | Used to put a background operation into the foreground. Opposite of bg. |
| file | Used to test arguments passed to the file. Tests for file system, magic number, or language. |
| find | looks for files in a directory. Example is:
find / -name *.bin -print |
| grep | Used to search a file or files for a particular string of text.
grep <text> <file> |
| groff | Part of the document formatting program, calls the troff program. |
| gzip | GNU type zip software.
gzip <filename> |
| halt | Used to shutdown the kernal…can only be done by root. |
| hostname | Used to display the current host or domain name of the system. |
| kill | Sends the term ( stop / terminate ) command to a specified process, unless a different signal is specified.
kill <option> <pid> |
| less | Used for backward movement in a file or forward movement. Searches files without having to read the entire file first. |
| login | Used to login to the system |
| logout | Used to logout of the system |
| lpc | Used to control the operation of the line printer system. |
| lpd | Line printer. daemon. Usually used at boot time it is use to search the /etc/printcap file to to find existing printers and jobs. |
| lpq | Used to examine the spooling area of lpd for files being printed and reports on the status of print jobs. |
| lpr | Used to print the named files. |
| ls | Used to list the contents of a directory. |
| make | Used to automatically determine which parts of a program need to be compiled and issued commands to compile them. |
| man | Used to display the manual pages of a utility.
man <utility name> |
| mesg | Used to send a message to a terminal or user for which you have permission |
| mkdir | Used to make a directory. |
| mkefs | Used to make an extended file system. |
| mkfs | Used to make a Linux / Unix file system on a device.
mkfs <filesystem> |
| mkswap | Used to set up a swap area on a device |
| more | Used to display one page of text at a time. Usually used with the pipe |
ls thisfile | more |
| mount | Used to attach file system. Can only be done by root. |
| mv | Used to move an object from one location to another or to replace a file with another file |
| netstat | Used to determine the status of a network and all the present connections |
| passwd | Used to change your password. |
| ps | Used to display a list of current processes. |
| pwd | Used to show you which directory you are in |
| rm | Used to delete files |
| rmdir | Used to delete directories |
| set | Used to temporarily change a variable in the environment |
| shutdown | Used to shutdown the system or specific areas of the system. |
| su | Used to change user to another user. |
| swapoff | Used to stop swaps to a file or device |
| swapon | Used to set the access to a swap device |
| tail | Used to display the end of a file
tail <number of lines starting at the end> <name of file> |
| talk | Used as a chat program for another user on another terminal. |
| tar | Used to store and extract files from an archive. |
| umount | Used to un-mount a file system |
| unalias | Used to unalias a command. |
| unzip | Used to extract files from a zip archive |
| wall | Used to display the contents of the standard input on all terminals of all logged on users. |
| who | Used to display who is logged onto the system |
| xhost + | Allows xTerms to be displayed on a system. |
| xmkmf | Used o create Imkaefiles for X sources. |
| xset | Used to set option in the X Windows system |
| zip | Used to add files to a zip archive. |