List of program for linux

General user

* dd – Convert and copy a file (Disk Dump)
* echo – Print to standard output
* env – Show environment variables; run a program with altered environment variables
* file – Determine the type of a file
* nohup – Run a command with immunity to hangups outputting to non-tty
* sh – The Bourne shell, the standard Unix shell
* uptime – Print how long the system has been running

System Management

* fuser – Identify processes by files or sockets
* logger – Make entries in the system log
* newgrp (or sg) – Log in to a new group
* pathchk – Check the validity/portability of filenames

Kernel specific

* date – Print or set the system date and/or time
* dmesg – Print the kernel message ring buffer
* ipcrm – Remove a message queue, semaphore set or shared memory id
* ipcs – Provide information on IPC facilities
* uname – Print assorted system statistics

Processes and tasks management

* anacron – Periodic command scheduler
* at – Single-time command scheduler
* chroot – Change the system root directory for all child processes
* cron – Periodic command scheduler
* crontab – Crontab file editor
* daemonic – Interface to daemon init scripts
* exit – Terminate the current shell process
* htop – Interactive ncurses-based process viewer that allows scrolling to see all processes and their full command lines
* kill – Send a signal to process, or terminate a process (by PID)
* killall – Terminate all processes (in GNU/Linux, it's kill by name)
* nice – Alter priorities for processes
* pgrep – Find PIDs of processes by name
* pidof – GNU/Linux equivalent of pgrep
* pkill – Send a signal to process, or terminate a process (by name). Equivalent to Linux killall
* ps – Report process status
* renice – Alter the priorities of an already running process
* sleep – Delay for specified time
* time – Time a command
* timex – Time process shell execution, measure process data and system activity
* top – Produce a dynamic list of all resident processes
* wait – Wait for the specified process
* watch – Runs the specified command repeatedly

Job Control

* bg – Resume a job in background
* jobs – Lists active jobs
* fg – Resume a job in foreground

User management and support

* chsh – Change user shell
* finger – Get details about user
* id – Print real/effective UIDs/GIDs
* last – show listing of last logged in users
* lastlog – show last log in information for users
* locale – Get locale specific information
* localedef – Compile locale definitions
* logname – Print user's login name
* man – Manual browser
* mesg – Control write access to your terminal
* passwd – Change user password
* su – Start a new process (defaults to shell) as a different user (defaults to root)
* sudo – execute a command as a different user.
* users – Show who is logged on (only users names)
* w – Show logged-in users and their current tasks
* whatis – command description from whatis database
* whereis – locates the command's binary and manual pages associated with it
* which (Unix) – locates where a command is executed from
* who – Show who is logged on (with some details)
* write – Send a message to another user

Terminal configuration

* stty – Change and print terminal line settings
* tput – Initialize a terminal/query terminfo database
* tty – Print filename of terminal connected to standard input

Files and texts

* info – The GNU alternative to man
* man – The standard unix documentation system

Filesystem Utilities

* chattr – Change file attributes on a Linux second extended file system
* chgrp – Change the group of a file or directory
* chmod – Change the permissions of a file or directory
* chown – Change the owner of a file or directory
* cd – Change to another directory location
* cp – Copy a file or directory to another location
* df – Report disk space
* dircmp – Compare contents of files between two directories
* du – Calculate used disk space
* fdupes – Find or remove duplicate files within a directory
* find – Search for files through a directory hierarchy
* fsck – Filesystem check
* ln – Link one file/directory to another
* ls – List directory contents
* lsattr – List file attributes on a Linux second extended file system
* lsof – list open files
* mkdir – Make a directory
* mkfifo – Make a named pipe
* mount – Mount a filesystem
* mv – Move or rename a file or directory
* pwd – Print the current working directory
* rm – Delete a file or directory tree
* readlink – Display value of a symbolic link, or display canonical path for a file
* rmdir – Delete an empty directory
* touch – Create a new file or update its modification time
* tree – Print a depth-indented tree of a given directory
* unlink – System call to remove a file or directory

Archivers and compression

* afio – Compatible superset of cpio with added functionality
* ar – Maintain, modify, and extract from archives. Now largely obsoleted by tar
* bzip2 – Block-sorting file compressor
* compress – Traditional compressor using the LZW algorithm
* cpio – A traditional archiving tool/format
* gzip – The gzip file compressor
* p7zip – 7zip for unix/linux
* pack, pcat, unpack – included in old versions of ATT Unix. Uses Huffman coding, obsoleted by compress.
* pax – POSIX archive tool that handles multiple formats.
* tar – Tape ARchiver, concatenates files
* uncompress – Uncompresses files compressed with compress.
* zcat – Prints files to stdout from gzip archives without unpacking them to separate file(s)

Text Processing

* awk – A pattern scanning and processing language
* banner – Creates ascii art version of an input string for printing large banners
* cat – Concatenate files to standard output
* cksum – Print the CRC checksum and bytecount of a file (see also MD5)
* cmp – Compare two files byte for byte
* comm – Sort two files and compare them line for line
* csplit – Split a file into sections determined by context lines
* cut – Remove sections from each line of a file or standard input
* diff3 – Compare one text file against two other files
* diff – Compare two text files line by line
* egrep – Extended pattern matching (synonym for "grep -E")
* expand – Convert tabs to spaces
* fc – Processes the command history list
* fgrep – Simplified pattern matching (synonym for "grep -F")
* fold – Wrap each input line to fit within the given width
* grep – Print lines matching a pattern
* head – Output the first parts of a file
* iconv – Convert the encoding of the specified files
* join – Join lines of two files on a common field
* less – Improved more-like text pager
* merge – Three way merge of files (see also paste)
* more – Pager
* nkf – Convert Japanese characters
* nl – Number the lines of a file
* nroff – Fixed-width (non-typesetter) version of the standard Unix typesetting system
* od – Dump files in various formats, e.g. octal
* paste – Merge lines of files
* patch – Change files based on a patch file
* rev – reverse lines of a file
* sed – Stream EDitor
* sort – Sort lines of text files
* split – Split a file into pieces
* tac – cat in reverse — displays files to standard output in reverse order starting at the end of the file
* tail – Output the tail end of files
* tee – Read from standard input, write to standard output and files
* tr – Translate characters
* tsort – Perform a topological sort
* unexpand – Convert spaces to tabs
* uniq – Remove duplicate lines from a sorted file
* uudecode – Decodes a binary file that was used for transmission using electronic mail
* uuencode – Encodes a binary file for transmission using electronic mail
* wc – Word/line/byte count

Text editors

* acme – Bitmapped text editor and integrated development environment ported from the Plan 9 operating system with client-server design, by Rob Pike. This is the successor of sam.
* ed – Original line-oriented, regular-expression based Unix text editor
* ex – Line-oriented text editor from BSD Unix, originally derived from Unix ed, later augmented by a screen-oriented "visual" mode, creating vi; typically a symbolic link to vi (or vim) causing it to start up in line-editing mode
* GNU Emacs – Freely programmable full-screen text editor and general computing environment (using builtin Elisp, a simple dialect of the Lisp programming language)
* Joe – a screen-oriented text editor using a Wordstar-style command set
* Jove – a screen-oriented text editor using an Emacs-style command set
* MicroEMACS – a screen-oriented text editor using an Emacs-style command set
* nano – Clone of pico (see below)
* NEdit – A Motif based text editor for the X11 windowing system, remniscient of text editors on Mac or Windows systems
* nvi – "New" vi, unencumbered (no remaining original Unix code) reimplementation of ex/vi for the 4.4BSD operating system release
* pico – PIne's message COmposition editor (simple, easy to use screen editor)
* sam – Bitmapped text editor ported from the Plan 9 operating system with client-server design, by Rob Pike
* vi – "Visual" (screen-oriented) text editor (originally ex in screen-oriented "visual" mode)
* VILE – "Vi like Emacs", a vi-like text editor that has been derived from the MicroEMACS text editor
* vim – Vi IMproved, portable vi-compatible editor with multiple buffers, screen splitting, syntax highlighting and a lot of other features not found in standard ex/vi
* XEmacs – Popular version of emacs that is derived from GNU Emacs

Communication, networking and remote access

* Apache webserver
* efax – integrated fax program
* ftp, sftp – File transfer protocol, secure FTP
* HylaFAX – Fax server
* netcat – "TCP/IP Swiss Army knife"
* NFS – Network filesystem
* OpenVPN – virtual private (encrypting) networking software
* Postfix — mail transfer agent
* rsh, SSH, telnet – Remote login
* Samba – SMB and CIFS client and server for UNIX
* Sendmail – popular E-Mail transport software
* talk – Talk to another logged-in user
* uustat – a Basic Networking Utilities (BNU) command that displays status information about several types of BNU operations
* uux – Remote command execution over UUCP

Email programs (user agents)

* elm – (Once very popular) screen-oriented mail program
* mail – Original Unix email program
* mailx/Mail – Improved version of Unix mail from BSD Unix
* Mulberry – powerful graphical IMAP-centric e-mail client (Proprietary Software)
* Mutt – screen-oriented mail program
* Opera – Web browser and e-mail client (Proprietary Software)
* Pine – screen-oriented mail and news program, originally derived from elm
* Mozilla Thunderbird – Extensible e-mail client

Network system services

* fingerd – a daemon for finger – a program used return a human-readable status report on either the system at the moment or a particular person in depth
* inetd – a daemon on many Unix systems that manages Internet services
* xinetd – replacement for inetd

Network Utilities

* dhclient – the DHCP client
* dhcpd – the DHCP daemon
* ifconfig – a tool used to configure a network interface for TCP/IP
* iwconfig – similar to ifconfig, but is dedicated to wireless networking interfaces
* ping – a network tool that tests of whether a particular host is up and reachable on the network
* pppd – Point-to-Point Protocol daemon
* tcpd – Secures programs launched from inetd

Network monitoring and security

* Ethereal and tethereal – a feature rich protocol analyzer (now called Wireshark, see below)
* ettercap – a tool for network protocol analysis
* John the Ripper – password cracking software
* Nessus – a comprehensive open-source network vulnerability scanning program
* Netstat – displays a list of the active network connections the computer
* Nmap – free port scanning software
* SAINT – System Administrator’s Integrated Network Tool – Network Vulnerability Scanner.
* SATAN – the Security Administrator Tool for Analyzing Networks – a testing and reporting tool that collects information about networked hosts
* Snoop – Solaris packet sniffer
* Snort – an open source network intrusion detection system
* tcpdump – a computer network debugging tool that intercepts and displays TCP/IP packets being transmitted or received
* Wireshark – a protocol analyzer, or "packet sniffer", similar to tcpdump, that adds a GUI frontend, and more sorting and filtering options (formerly named Ethereal)

Programming tools

Script Interpreters

Shells

* bash – Bourne Again SHell, (mostly) sh-compatible and csh-compatible, standard shell on Linux systems and Mac OS X.
* csh – C shell. Written by Bill Joy for BSD systems.
* ksh – Korn shell, standard shell on many proprietary Unix systems, powerful successor to the Unix Bourne shell (sh), written by David Korn,
* rc – originally written for Plan 9.
* sh – Bourne shell, only shell present on all UNIX and Unix-like systems, written by Stephen Bourne for Version 7 Unix.
* tcsh – TENEX C shell, standard shell on BSD systems.
* zsh – Z shell.

Non-shells

* awk – Standard Unix pattern scanning and text processing tool.
* perl – Perl scripting language.
* PHP – PHP scripting language.
* Python – Python scripting language.

Compilers and Programming tools

The classic UNIX environment includes a basic set of broadly available programming tools, but in the 21st century this classic environment is increasingly rare, as Unix-like operating system distributions diversify. Some include vastly more, and more modern and sophisticated, programming tools and environments, whereas others, focussing on serving a less technical audience, may exclude even the most rudimentary programming utilities. Commands most familiar to a prior generation of UNIX users include:

* admin – Administer SCCS files.
* as – GNU assembler tool.
* c99 – C programming language.
* cc – C compiler.
* cfront – C++ front-end compiler
* ctags – Generate tags file summarising location of objects in source files.
* dbx – (System V and BSD) Symbolic debugger.
* distcc – Tool for distributing compiles across multiple machines.
* f77 – Fortran 77 compiler.
* gcc – GNU Compiler Collection C frontend (also known as GNU C Compiler)
* gdb – GNU symbolic debugger.
* ktrace – (BSD) Analogous to strace.
* ld – Program linker.
* lex – Lexical scanner generator.
* ltrace – (Linux) Trace dynamic library calls in the address space of the watched process.
* m4 – Macro language.
* make – Automate builds.
* nm – List symbols from object files.
* rmdel – remove a delta from an SCCS file.
* size – return the size of the sections of an ELF file.
* strace – (Linux) or truss (Solaris) Trace system calls with their arguments and signals. Useful debugging tool, but does not trace calls outside the kernel, in the address space of the process(es) being watched.
* strip – Remove debugging symbols from object files.
* yacc – LALR parser generator.

Scripting utilities

* basename – Returns the final component of a path
* batch – Runs jobs when the system load level permits
* false – Return a value that evaluates as False
* hash – Command that remembers or reports command path names
* printf – Format and print data
* strings – Print strings of printable characters found in a file
* test – Test an expression
* times
* true – Return a value that evaluates as True
* unset – Unsets a shell variable
* xargs – Build and execute command lines from standard input
* expr – Evaluate expressions

User interfaces

* X11 – Graphical user interface (GUI)
o startx and xinit
o xterm

Desktops/Graphical User Interfaces

* Blackbox and its variants (including Fluxbox and Waimea)
* CDE – Common Desktop Environment, most commonly found on proprietary UNIX systems
* Enlightenment – an open source window manager for the X Window System
* FVWM and its variant FVWM95, which has been modified to behave like Windows 95 Also FVWM-Crystal that aims to be eye candy
* GNOME – GNU Network Object Model Environment
* IceWM – ICE Window Manager
* Ion (window manager) – tiling and tabbing window manager for the X Window System. Designed for use without a mouse.
* JWM – Joe's Window Manager
* KDE – K Desktop Environment
* Quartz Compositor – Apple's GUI interface for the Darwin BSD based operating system Mac OS X
* Window Maker
* WMI – Window Manager Improved
* XFce – a desktop environment for Unix and other Unix-like platforms
* EDE

Shells

See Script Interpreters.

Computer security

Antivirus software

* ClamAV – E-mail virus scanner.

Cryptography

* Enigmail – Graphical interface to gpg for Mozilla Application Suite and Mozilla Thunderbird.
* gpg – GNU Privacy Guard, a complete and free replacement for PGP (to do file and email encryption and signature).
* mcrypt -- Replacement for the legacy crypt program; can also make OpenPGP-compatible files.
* openssl – Secure Sockets Layer and general crypto library.
* pinepgp – Filters that enable pine to use signed/encrypted email.

Package management software

* apt – Front-end for dpkg or rpm
* debconf – Debian package configuration management system
* dpkg – The Debian package manager
* drakconf – Front-end configuration utility for Mandriva Linux
* emerge – A frontend to portage
* pacman – A package manager used primarily by Arch Linux
* portage – The Gentoo Linux package manager
* rpm – Originally the package manager for Red Hat Linux, now used by several distributions including Mandriva Linux
* Synaptic – GTK+ frontend for the apt package manager. Primarily used by Ubuntu Linux, Debian Sarge, and other Debian-based systems; but usable on any system using apt.
* urpmi – Front-end to rpm, used by Mandriva Linux
* YaST - System management utility mainly used by SuSE
* yum - Front-end for rpm, used by Fedora

OS X/Darwin specific programs

* defaults (software) – Access the Mac OS X user defaults system
* fink – The Fink package manager
* open – opens it's argument(s) in the GUI as if the user had double clicked
* osacompile – Compile AppleScripts and other OSA language scripts
* osalang – Information about installed OSA languages
* osascript – Execute AppleScripts and other OSA language scripts
* say – Convert text to audible speech

Application software

Office

* AbiWord
* Gnumeric
* KOffice
* OpenOffice.org

Multimedia

* Amarok – Audio jukebox
* Ardour – Digital audio workstation for multitrack HD recording and editing
* Audacity – Sound recording and editing program
* Baudline – Audio recorder, analyzer, and player
* GIMP – Powerful image manipulation package
* GStreamer – Plugin-based multimedia framework
* ImageMagick – Image conversion library
* Inkscape – Vector graphics editor
* mpg123 – MP3 player
* MPlayer – General-purpose media player
* Netpbm – package of graphics programs and programming library
* Rhythmbox – Audio jukebox similar to Apple's iTunes
* Rosegarden – Powerful digital audio workstation
* SoX – Sound conversion tool
* Totem – Media player
* transcode – Flexible command-line media encoding tool
* VLC media player – Video player
* xine – Video Player
* XMMS – Winamp-like multimedia player

Web browsers

* Dillo – Extremely light-weight web browser
* ELinks – Enhanced links
* Epiphany – Light-weight GNOME web browser
* Galeon – Light-weight old GNOME web browser
* Konqueror – KDE web browser
* Links – Console based web browser
* lynx – Console based web browser
* Mozilla Application Suite – Graphical cross platform web browser & email client
* Mozilla Firefox – Extensible Web browser
* Opera – Web browser and e-mail client (Proprietary Software)
* w3m – Console based web browser

Desktop Publishing

* groff – Traditional typesetting system
* LaTeX – Popular TeX macro package for higher-level typesetting
* lp – Print a file (on a line printer)
* Passepartout – Desktop publishing program
* pr – Convert text files for printing
* Scribus – Desktop publishing program
* TeX – Macro-based typesetting system
* troff – The original and standard Unix typesetting system

Databases

* DB2
* Firebird
* MySQL
* Oracle
* PostgreSQL
* Progress Software
* SQLite
* Sybase

Mathematical and scientific software

* maxima – Symbol manipulation program.
* octave – Numerical computing language (mostly compatible with Matlab) and environment.
* R – Statistical programming language.
* units – Unit conversion program.

Desktop utilities

* bc – An arbitrary precision calculator language with syntax similar to the C programming language.
* cal – Displays a calendar
* dc – Reverse-Polish desk calculator which supports unlimited precision arithmetic
* fortune – Fortune cookie program that prints a random quote