Free software programmed in C

visual audio programming language

Sendmail is a general purpose internetwork email routing facility that supports many kinds of mail-transfer and delivery methods, including the Simple Mail Transfer Protocol (SMTP) used for email transport over the Internet.

xine is a multimedia playback engine for Unix-like operating systems released under the GNU General Public License. xine is built around a shared library (xine-lib) that supports different frontend player applications. xine uses libraries from other projects such as liba52, libmpeg2, FFmpeg, libmad, FAAD2, and Ogle. xine can also use binary Windows codecs through a wrapper, bundled as the w32codecs, for playback of some media formats that are not handled natively.

free and open-source library for 3D graphics rendering

Leafpad is a free and open-source graphical text editor for Linux, Berkeley Software Distribution (BSD), and Maemo that is similar to the Microsoft Windows program Notepad. Created with the focus of being a lightweight text editor with minimal dependencies, it is designed to be simple-to-use and easy-to-compile.

tmux is an open-source terminal multiplexer for Unix-like operating systems. It allows multiple terminal sessions to be accessed simultaneously in a single window. It is useful for running more than one command-line program at the same time. It can also be used to detach processes from their controlling terminals, allowing remote sessions to remain active without being visible.

free software IMAP and POP3 server

SPICE (Simulation Program with Integrated Circuit Emphasis) is a general-purpose, open-source analog electronic circuit simulator. It is a program used in integrated circuit and board-level design to check the integrity of circuit designs and to predict circuit behavior.

library for numerical analysis in C and C++

HandBrake is a free and open-source transcoder for digital video files. It was originally developed in 2003 by Eric Petit to make ripping DVDs to a data storage device easier. HandBrake's backend contains comparatively little original code; the program is an integration of many third-party audio and video libraries, both codecs (such as FFmpeg, x264, and x265) and other components such as video deinterlacers (referred to as "filters"). These are collected in such a manner to make their use more effective and accessible (e.g., so that a user does not have to transcode a video's audio and visual

KornShell (ksh) is a Unix shell which was developed by David Korn at Bell Labs in the early 1980s and announced at USENIX on July 14, 1983. The initial development was based on Bourne shell source code. Other early contributors were Bell Labs developers Mike Veach and Pat Sullivan, who wrote the Emacs and vi-style line editing modes' code, respectively. KornShell is backward-compatible with the Bourne shell and includes many features of the C shell, inspired by the requests of Bell Labs users.

HTTrack is a free and open-source Web crawler and offline browser, developed by Xavier Roche and licensed under the GNU General Public License Version 3.

PulseAudio is a network-capable sound server program distributed via the freedesktop.org project. It runs mainly on Linux, including Windows Subsystem for Linux on Microsoft Windows and Termux on Android; various BSD distributions such as FreeBSD, OpenBSD, and macOS; as well as Illumos distributions and the Solaris operating system. It serves as a middleware in between applications and hardware and handles raw PCM audio streams.

GNOME window manager and display server

distributed protocol for telephony and instant messaging

file manager bundled with Microsoft Windows in the 1990s, now open source and ported to modern Windows

MicroPython is a software implementation of a programming language largely compatible with Python 3, written in C, that is optimized to run on a microcontroller.

PHP scripting engine

software installer for several Linux distributions

PackageKit is a free and open-source suite of software applications designed to provide a consistent and high-level abstraction layer for a number of different package management systems. PackageKit was created by Richard Hughes in 2007, and first introduced into an operating system as a default application in May 2008 with the release of Fedora 9.

software interface for Unix-like operating systems that lets non-privileged users create file systems without editing kernel code

free optical character recognition engine

software library for video game development

OpenVZ (Open Virtuozzo) is an operating system-level virtualization technology for Linux. It allows a physical server to run multiple isolated operating system instances, supporting containerization, virtual private servers (VPSs) and virtual environments (VEs). OpenVZ is similar to Solaris Containers and LXC.

OpenLDAP is a free, open-source implementation of the Lightweight Directory Access Protocol (LDAP) developed by the OpenLDAP Project. It is released under its own BSD-style license called the OpenLDAP Public License.

member of the Perl family of programming languages

software library providing embedded database for key/value data

terminal emulator from GNOME

twm is a window manager for the X Window System. Started in 1987 by Tom LaStrange, it has been the standard window manager for the X Window System since version X11R4. The name originally stood for '''Tom's Window Manager, but the software was renamed Tab Window Manager''' by the X Consortium when they adopted it in 1989. twm is a stacking window manager that provides title bars, shaped windows and icon management. It is highly configurable and extensible.

qmail is a mail transfer agent (MTA) that runs on Unix. It was written, starting December 1995, by Daniel J. Bernstein as a more secure alternative to the popular Sendmail program. Originally license-free software, qmail's source code was later dedicated to the public domain by the author.

multi-platform free software boot loader

In the field of computer network administration, pcap is an application programming interface (API) for capturing network traffic. While the name is an abbreviation of packet capture, that is not the API's proper name. Unix-like systems implement pcap in the libpcap library; for Windows, there is a port of libpcap named WinPcap that is no longer supported or developed, and a port named Npcap for Windows 7 and later that is still supported.

Lincity is a free and open-source construction and management simulation game, which puts the player in control of managing a city's socio-economy, similar in concept to SimCity. The player can develop a city by buying appropriate buildings, services and infrastructure. Its name is both a Linux reference and a play on the title of the original city-building game, SimCity, and it was released under the GNU General Public License v2.

VeraCrypt is a free and open-source utility for on-the-fly encryption (OTFE). The software can create a virtual encrypted disk that works just like a regular disk, but within a file. It can also encrypt a partition or (in Microsoft Windows) the entire storage device with pre-boot authentication.

htop is an interactive system monitor process viewer and process manager. It is designed as an alternative to the Unix program top.

Rockbox is a free and open-source software replacement for the OEM firmware in various forms of digital audio players (DAPs) with an original kernel. It offers an alternative to the player's operating system, in many cases without removing the original firmware, which provides a plug-in architecture for adding various enhancements and functions. Enhancements include personal digital assistant (PDA) functions, applications, utilities, and games. Rockbox can also retrofit video playback functions on players first released in mid-2000. Rockbox includes a voice-driven user-interface suitable for o

Illumos (stylized as "illumos") is a partly free and open-source Unix operating system. It has been developed since 2010 and is based on OpenSolaris, after the discontinuation of that product by Oracle. It comprises a kernel, device drivers, system libraries, and utility software for system administration. Its core has become the base for many different open-sourced Illumos distributions, in a way similar to how the Linux kernel is used in different Linux distributions.

zero-configuration networking (zeroconf) implementation

thumb|RRDtool has a graph function, which presents data from an RRD in a customizable graphical format.

Praat ( ; ) is a free, open-source computer software package widely used for speech analysis and synthesis in phonetics and other fields of linguistics. The software was developed and is maintained by Paul Boersma and David Weenink at the University of Amsterdam, and is compatible most major operating systems, including Unix, Linux, Mac, and Microsoft Windows. Praat has been used in linguistic research on endangered and minority languages, as well as for analyzing regional accents and phonetic variation.

iPodLinux is a μClinux-based Linux distribution designed specifically to run on Apple Inc.'s iPod. When the iPodLinux kernel is booted it takes the place of Apple's iPod operating system and automatically loads Podzilla, an alternative GUI and launcher for a number of additional included programs such as a video player, an image viewer, a command line shell, games, emulators for video game consoles, programming demos, and other experimental or occasionally unfinished software.

CD-Ripper

Sodipodi is a free and open-source vector graphics editor, superseded since 2003 by Inkscape, an independent Sodipodi fork.

thumb|Simplified software architecture of GTK, [[Pango, GDK, ATK, GIO, Cairo and GLib.]] GLib is a bundle of three (formerly five) low-level system libraries written in C and developed mainly by GNOME. GLib's code was separated from GTK, so it can be used by software other than GNOME and has been developed in parallel ever since.

PSPP is a free software application for analysis of sampled data, intended as a free alternative for IBM SPSS Statistics. It has a graphical user interface and conventional command-line interface. It is written in C and uses GNU Scientific Library for its mathematical routines. The name has "no official acronymic expansion".

gThumb is a free and open-source image viewer and image organizer with options to edit images. It is designed to have a clean and simple user interface and follows the GNOME Human Interface Guidelines and integrates well with the GNOME desktop environment.

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web browser

BitchX is a free IRC client that has been regarded as the most popular ircII-based IRC client. The initial implementation, written by "Trench" and "HappyCrappy", was a script for the IrcII chat client. It was converted to a program in its own right by panasync (Colten Edwards). BitchX 1.1 final was released in 2004. It is written in C and is a TUI application utilizing ncurses. GTK+ toolkit support has been dropped. It works on all Unix-like operating systems, and is distributed under a BSD license. It was originally based on ircII-EPIC, and eventually it was merged into the EPIC IRC client. I

malware that turns computer systems running Linux into remotely controlled "bots"

NetSurf is an open-source web browser which uses its own layout engine. Its design goal is to be lightweight and portable. NetSurf provides features including tabbed browsing, bookmarks, and page thumbnailing.

WeeChat (Wee Enhanced Environment for Chat) is a free and open-source Internet Relay Chat client that is designed to be light and fast. It is released under the terms of the GNU GPL-3.0-or-later and has been developed since 2003.

TestDisk is a free and open-source data recovery utility that helps users recover lost partitions or repair corrupted filesystems. TestDisk can collect detailed information about a corrupted drive, which can then be sent to a technician for further analysis. TestDisk supports DOS, Microsoft Windows (i.e. NT 4.0, 2000, XP, Server 2003, Server 2008, Vista, Windows 7, Windows 8.1, Windows 10), Linux, FreeBSD, NetBSD, OpenBSD, SunOS, and MacOS. TestDisk handles non-partitioned and partitioned media. In particular, it recognizes the GUID Partition Table (GPT), Apple partition map, PC/Intel BIOS par

ratpoison is a tiling window manager for the X Window System primarily developed by Shawn Betts. The user interface and much of their functionality are inspired by the GNU Screen terminal multiplexer. While ratpoison is written in C, Betts' StumpWM re-implements a similar window manager in Common Lisp.

GTK-based Email client

Squashfs is a compressed read-only file system for Linux. Squashfs compresses files, inodes and directories, and supports block sizes from 4 KiB up to 1 MiB for greater compression. Several compression algorithms are supported. Squashfs is also the name of free software, licensed under the GPL, for accessing Squashfs filesystems.

System monitor for X

open source software driver for Nvidia GPU

Virtual machine designed to run various dynamic programming languages

framework for multilingual input