Editing Free software (section)

=={{anchor|Definition}}Definition and the Four Essential Freedoms of Free Software==

{{Main|The Free Software Definition}}
{{See also|Debian Free Software Guidelines|The Open Source Definition}}
[[File:Categories of free and nonfree software.svg|thumb|300px|Diagram of free and nonfree software, as defined by the Free Software Foundation. Left: free software, right: proprietary software, encircled: [[Freeware|gratis software]]]]

The first formal definition of free software was published by FSF in February 1986.<ref name="bull6" /> That definition, written by [[Richard Stallman]], is still maintained today and states that software is free software if people who receive a copy of the software have the following four freedoms.<ref name="free-sw" /><ref>{{cite news|url=https://fsfe.org/freesoftware/#freedoms|title=Four Freedoms|work=fsfe.org|access-date=March 22, 2022}}</ref> The numbering begins with zero, not only as a spoof on the common usage of [[zero-based numbering]] in programming languages, but also because "Freedom 0" was not initially included in the list, but later added first in the list as it was considered very important.
* Freedom 0: The freedom to use the program for any purpose.
* Freedom 1: The freedom to study how the program works, and change it to make it do what you wish.
* Freedom 2: The freedom to redistribute and make copies so you can help your neighbor.
* Freedom 3: The freedom to improve the program, and release your improvements (and modified versions in general) to the public, so that the whole community benefits.

Freedoms 1 and 3 require [[source code]] to be available because studying and modifying software without its source code can range from highly impractical to nearly impossible.

Thus, free software means that [[User (computing)|computer users]] have the freedom to cooperate with whom they choose, and to control the software they use. To summarize this into a remark distinguishing ''libre'' (freedom) software from ''[[Gratis versus libre|gratis]]'' (zero price) software, the Free Software Foundation says: "Free software is a matter of liberty, not price. To understand the concept, you should think of 'free' as in '[[freedom of speech|free speech]]', not as in 'free beer{{'"}}.<ref name="free-sw" /> (''See [[Gratis versus libre]].'')

In the late 1990s, other groups published their own definitions that describe an almost identical set of software. The most notable are ''[[Debian Free Software Guidelines]]'' published in 1997,<ref name="Perens" /> and ''[[The Open Source Definition]]'', published in 1998.

The [[Berkeley Software Distribution|BSD]]-based operating systems, such as [[FreeBSD]], [[OpenBSD]], and [[NetBSD]], do not have their own formal definitions of free software. Users of these systems generally find the same set of software to be acceptable, but sometimes see [[copyleft]] as restrictive. They generally advocate [[permissive free software license]]s, which allow others to use the software as they wish, without being legally ''forced'' to provide the source code. Their view is that this permissive approach is more free. The [[Kerberos (protocol)|Kerberos]], [[MIT License|X11]], and [[Apache License|Apache]] software licenses are substantially similar in intent and implementation.