(Or utility program, tool) Any software that performs some specific task that is secondary to the main purpose of using the computer (the latter would be called application programs) but is not essential to the operation of the computer (system software).

Many utilities could be considered as part of the system software, which can in turn be considered part of the operating system.

The following are some broad categories of utility software, specific types and examples.

* Disks

disk formatter: FDISK, format

defragmenter

disk checker: fsck

disk cleaner

system profiler

backup

file system compression

* Files and directories

list directory: ls, dir

copy, move, remove: cp, mv, rm, xcopy

archive: tar

compression: zip

format conversion: atob

comparison: diff

sort: sort

* Security

authentication: login

antivirus software: avast, Norton Antivirus

firewall: Zone Alarm, Windows firewall

encryption: gpg)

* Editors for general-purpose formats (as opposed to specific formats like a word processing document)

text editor: Emacs

binary editor, hex editor

* Communications

mail transfer agent: sendmail

e-mail notification: biff

file transfer: ftp, rcp, Firefox

file synchronisation: unison, briefcase

chat: Gaim, cu

directory services: bind, nslookup, whois

network diagnosis: ping, traceroute

remote access: rlogin, ssh

* Software development

compiler: gcc

build: make, ant

codewalker

preprocessor: cpp

debugger: adb, gdb

installation: apt-get, msiexec, patch

compiler compiler: yacc

* Hardware

device configuration: PCU, devman, stty