The Four Essential Freedoms of Free Software Users

“自由软件”尊重用户的自由，并且尊重整个社区。粗略来讲，一个软件如果是自由软件，这意味着用户可以自由地运行，拷贝，分发，学习，修改并改进该软件。因此，“自由软件”是关乎自由的问题，与价格无关。要理解这个概念，你要按照 Free Software 中的“Free”是指“自由言论（free speech）”中的自由，而非“免费午餐（free lunch）”的免费这一意项。为避免歧义，在使用英文时，我们也会借用法语或西班牙语的“Libre Software”来指自由软件，这样可以明确表示我们说的不是免费。

“Free software” means software that respects users' freedom and community. Roughly, it means that the users have the freedom to run, copy, distribute, study, change and improve the software. Thus, “free software” is a matter of liberty, not price. To understand the concept, you should think of “free” as in “free speech,” not as in “free beer.” We sometimes call it “libre software,” borrowing the French or Spanish word for “free” as in freedom, to show we do not mean the software is gratis.

你可能花钱购买了自由软件的拷贝，也可能免费拿到。但是无论你如何获得你的拷贝，你都有自由复制和修改该软件，乃至 出售 该软件的拷贝。

You may have paid money to get copies of a free program, or you may have obtained copies at no charge. But regardless of how you got your copies, you always have the freedom to copy and change the software, even to sell copies.

我们支持软件用户的自由，因为我们坚信这是每个用户应得的。有了这些自由，软件用户，无论是个人还是集体，都可以掌控所运行的软件，并决定这些程序如何为自己服务。如果一个软件令用户失去了这种控制权，我们则称它为“非自由”的，或“专有”的程序。与自由软件相反，非自由软件会操控它的用户，而软件的开发者则掌控着软件。这使得非自由软件成为了非正义力量的帮凶。

We campaign for these freedoms because everyone deserves them. With these freedoms, the users (both individually and collectively) control the program and what it does for them. When users don't control the program, we call it a “nonfree” or “proprietary” program. The nonfree program controls the users, and the developer controls the program; this makes the program an instrument of unjust power.

“开源”是另外一回事：它有基于不同价值观的非常不同的哲学。其实际定义也不同，但是几乎所有的开源程序事实上都是自由软件。我们在为什么“开源”错失了自由软件的重点一文中阐述了这些不同。

“Open source” is something different: it has a very different philosophy based on different values. Its practical definition is different too, but nearly all open source programs are in fact free. We explain the difference in Why “Open Source” misses the point of Free Software.

一个程序是自由软件，如果该程序的用户（这里指像“你”一样的个体）拥有四个基本自由：[1]

A program is free software if the program's users (referred to individually here as “you”) have the four essential freedoms: [1]

• 自由之零：无论用户出于何种目的，必须可以按照用户意愿，自由地运行该软件。
• The freedom to run the program as you wish, for any purpose (freedom 0).
• 自由之一：用户可以自由地学习并修改该软件，以此来帮助用户完成用户自己的计算。作为前提，用户必须可以访问到该软件的源代码。
• The freedom to study how the program works, and change it so it does your computing as you wish (freedom 1). Access to the source code is a precondition for this.
• 自由之二：用户可以自由地分发该软件的拷贝，这样就可以助人。
• The freedom to redistribute copies so you can help others (freedom 2).
• 自由之三：用户可以自由地分发该软件修改后的拷贝。借此，用户可以把改进后的软件分享给整个社区令他人也从中受益。作为前提，用户必须可以访问到该软件的源代码。
• The freedom to distribute copies of your modified versions to others (freedom 3). By doing this you can give the whole community a chance to benefit from your changes. Access to the source code is a precondition for this.

如果一个程序充分赋予用户所有这些自由，那么它就是自由软件。否则，它就是非自由软件。虽然我们可以根据其背离自由程度的不同来区分各种非自由软件的发行模式，但是我们认为它们在道德上都一样不可接受。

A program is free software if it gives users adequately all of these freedoms. Otherwise, it is nonfree. While we can distinguish various nonfree distribution schemes in terms of how far they fall short of being free, we consider them all equally unethical.

无论在哪种情况下，只有所有用户使用的代码都满足了这四项基本自由，该程序才能被视作自由软件。例如，有两个程序，甲程序运行的时候会自动调用乙程序。发布甲程序意味着用户必须使用到乙程序，那么必须甲乙两个程序都是自由的，甲程序才是自由的。如果通过修改甲程序，使其不再依赖乙程序，那么仅仅以自由软件的形式发布甲程序即可。

In any given scenario, these freedoms must apply to whatever code we plan to make use of, or lead others to make use of. For instance, consider a program A which automatically launches a program B to handle some cases. If we plan to distribute A as it stands, that implies users will need B, so we need to judge whether both A and B are free. However, if we plan to modify A so that it doesn't use B, only A needs to be free; B is not pertinent to that plan.

1. 使用0、1、2和3排列这些自由有历史的原因。在1990年左右，列出来的自由是1、2和3。然后，我们意识到运行软件的自由也应该明确列出来。这个自由显然比另外3个自由更基本，所以应该列在前面。我们没有修改其他3个自由的序号，而是将运行软件的自由列为 0。
2. The reason they are numbered 0, 1, 2 and 3 is historical. Around 1990 there were three freedoms, numbered 1, 2 and 3. Then we realized that the freedom to run the program needed to be mentioned explicitly. It was clearly more basic than the other three, so it properly should precede them. Rather than renumber the others, we made it freedom 0.

Source: "What is Free Software?" by the Free Software Foundation, and its official Simplified Chinese translation. Only the introduction and the section on the four essential freedoms are reproduced, paragraph by paragraph in Chinese and English. The text is verbatim and unmodified, under the Creative Commons Attribution-NoDerivatives 4.0 International license. Only the headings, the footnote anchors and the site-relative links were adjusted for this page.