What is the GPL license for Linux

Introduction¶

Without good tools and a helpful team, any job is only half as fun. At this point I would like to briefly state which principles and technical properties have convinced me of Linux and the open source concept and which applications and scripts have helped me in many situations since then.

The basic idea of ​​open source

Open source can be understood as a common principle of cooperation - it is therefore not tied to a special operating system. Numerous open source programs such as Firefox, Thunderbird, LibreOffice, VLC, Gimp, and Inkscape can now be found on many operating systems. [1] The open source mentality was best known, however, through Linux, which is based entirely on free software.

Everyone can download, use and (depending on the license) also modify free software and operating systems free of charge. Sourceforge, for example, provides an overview of numerous open source programs - regardless of the operating system. The Ubuntuusers Wiki, for example, provides an overview of Linux software.

The historical development of Open Source and Linux

The open source movement arose when some software companies began selling software to their customers no longer in the form of source code, but as programs that had already been converted into machine code. Although these were readable for computers, they were no longer readable for humans.

Many programmers feared a loss of control on the part of the customer and criticized the lack of information flow on the part of the software manufacturer. In addition - in combination with the patenting of "intellectual property" - the equality of programmers was seen as endangered. It was feared that the know-how would quickly concentrate on only a few companies.

In order to counteract such patenting of information and the resulting technical and legal problems, the “Open Source” movement and the “Free Software Foundation” were brought into being and the development of joint, freely available software began ]

In the 1970s and 1980s, the GNU project, which encompasses numerous free software and even brought with it its own license regulation (GNU General Public License (GPL)), was born. The basic ideas, the source code libraries and the legal basis ultimately formed the basis for the new "Linux" operating system in the 1990s. [3]

"Free Speech" and "Free Beer"

In the case of open source software, the source code can always be viewed freely; you can always download and install such software free of charge and use it legally as a private user without any further restrictions.

“Freedom”, however, is a difficult term to define; For example, there are big differences between free speech and free beer. Applying this comparison to open source software, one can say that the first principle always applies to all open source software: The source code is always freely accessible, so you can "see" how the respective programs work at any time , and consequently download and install them legally.

On the other hand, you have to pay attention to the individual licenses if the source code of individual programs is to be modified or expanded to include additional functionalities. The source code doesn't “belong” to you (in the sense of “free beer”), so you don't just add code to it, for example, and then use or even use the result commercially as your own program (possibly even without publishing the modified source code) on a web server may sell.

The most important open source licenses are as follows:

  • Programs under a GPL license may be used freely (also commercially) at any time; Changes to the source code must, however, also be subject to a GPL license (copyleft principle). In addition, GPL code may not be incorporated into other proprietary software.
  • Programs under an LGPL or Apache license may also be used freely; Changes and extensions may, however, also be under other licenses. These licenses thus soften the copyleft principle and also allow proprietary extensions (in which the users then have to pay attention to the respective license texts).
  • In the case of works that are under a Creative Commons license (CCL) (often books, texts, images, etc.), there are various "degrees of freedom" that the author of the work can determine himself. For example, if the addition "nd" (No Derivatives) is used, the work may be used but not modified; if the addition “nc” (non-commercial) is used on the other hand, commercial use is prohibited.

Use, understand, participate!

The Linux and open source community not only invites you to download and use a variety of programs for free - they also endeavor to make users understand the benefits of open source projects and how software works. In a team in which everyone benefits from the work of everyone else, further "colleagues" are welcome at any time .. :-)

With Linux as the operating system, every user has the opportunity to look at the source code of other programmers and - by reading and writing their own code - to become a software developer themselves.

But not only source code is important: All information that is published under a non-profit license such as the Creative Commons License (CCL) or the General Public License (GPL) contributes to the freely accessible wealth of knowledge and thus to the common good of society!


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