The free software movement is a social movement with the goal of obtaining and guaranteeing certain freedoms for software users, namely the freedoms to run, study, modify, and share copies of software. Software which meets these requirements, The Four Essential Freedoms of Free Software, is termed free software.
GNU and Tux mascots around free software supporters at FISL 16
Free software, libre software, or libreware is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, not price; all users are legally free to do what they want with their copies of a free software regardless of how much is paid to obtain the program. Computer programs are deemed "free" if they give end-users ultimate control over the software and, subsequently, over their devices.
Creating a 3D car racing game using the Blender Game Engine.
Although nearly all computer viruses only affect Microsoft Windows, antivirus software such as ClamTk (shown here) is still provided for Linux and other Unix-based systems, so that users can detect malware that might infect Windows hosts.