Free software movement refers to a social and technical campaign that promotes users' rights to control the computer programs they use. Advocates seek to reduce reliance on proprietary applications by encouraging software whose code and licensing allow users to run, examine, modify, and share it. Distributions such as Ubuntu are often used to make these freedoms accessible to everyday users.
Core principles
Supporters of the movement commonly describe four essential freedoms that define free software:
- The freedom to run the program for any purpose.
- The freedom to study how the program works and adapt it (access to source code is required).
- The freedom to redistribute copies so others can benefit.
- The freedom to improve the program and release those improvements to the public.
Relation to open source
The free software movement and the open source community overlap substantially: both produce and use software with source code available. However, free software emphasizes ethical and user-rights arguments, while open source tends to highlight practical benefits like reliability, security, and cost-effectiveness.
Common examples
Many widely used projects illustrate the movement's approach to software development and distribution. Web browser and client programs include Mozilla Firefox and Mozilla Thunderbird, and file-transfer utilities such as FileZilla are also common. Entire operating systems built around these ideas include the kernel-based Linux distributions and alternative efforts like ReactOS.
Opposition to proprietary software
Advocates criticize software that imposes restrictions on copying, studying, or modifying code. Examples of widely used proprietary applications that the movement opposes include Microsoft Windows and Adobe Acrobat; other commercial editors such as UltraEdit are also cited as non-free because they limit user freedoms.
Meaning of “free”
The term "free" in this context refers to liberty rather than price. A common way to express the distinction is: think of “free” as in free speech, not necessarily free beer. The emphasis is on freedom to use, share, and change software rather than on whether it costs money.