> For the complete documentation index, see [llms.txt](https://olb.gitbook.io/linux-essentials-certification/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://olb.gitbook.io/linux-essentials-certification/1.linux_community/1.3-open_source_licensing.md).

# 1.3 Open Source licensing

**Weight 1**\
Key knowledge areas

* Open source philosophy
* Open source licensing
* Free Software Foundation (FSF), Open Source Initiative (OSI)

Partial list of the used files, terms and utilities

* Copyleft, Permissive
* GPL, BSD, Creative Commons
* Free Software, Open Source Software, FOSS, FLOSS
* Open source business models

***

## Free software

* Free Software foundation (FSF) - Richard Stallman - 1985 - GNU project
* 4 freedoms
  * 0: run the program
  * 1: study and modify w/ access to the source code
  * 2: distribute the program
  * 3: distribute modified program

## Open Source Software Vs Free Software

* FOSS / FLOSS : Free (Libre) Open Source Software
* Free Software foundation (FSF) - Richard Stallman - 1985
* starts w/ GNU (GNU is Not Unix)
* FSF : social ideology but not always pragmatic
* OSI : Open Software Initiative is more pragmatic and business oriented

## Licenses

### copyleft (GNU licences)

* GPL : General Public License (Linux kernel, MySQL, MariaDB, Wordpress) - strong copyleft
* LGPL : Lesser GPL ( for libraries) - no need to publish modified code can run with other non-free components
* AGPL : Hosted software - source code can be downloaded - strong copyleft
* FDL: Free Documentation License for documentation
* License conflict is possible
  * LGPL is a solution
  * Dual licensing (free version w/ copyleft OR commercial version)

### permissive (OSI licenses)

* BSD / Simplified BSD : Berkeley Software Distribution - (NetBSD, OpenBSD, FreeBSD projects, Nginx, Python...)
* Apache v2.0 License (Apache, Android, Rancher ...)
* MIT (Node.js, React, Leaflet, jQuery)

### Creative Commons

Licensing for creative or knowledge content 6 licenses

* CC BY : name the author
* CC BY-SA : name the author + copyleft (if modified same license)
* CC BY-ND : no derivatives (no modification)
* CC BY-NC : non commercial usage
* CC BY-NC-SA : non commercial + copyleft
* CC BY-NC-ND : most restrictive

## Business models w/ OSS

* crowdfunding
* dual licensing (ownCloud)
* services (maintenance, consulting)
* SaaS
* paid / proprietary extensions, custom developpement