The acronym GNU is most often used for "GNU is not Unix". It is a project that was started in 1984 by the Free Software Foundation (FSF). The goal of the GNU project was to develop an open, license-free operating system that would be similar to Unix.
The development initiative was influenced by the concurrent development of Linux, with the developer of the Linux kernel, Linus Torvalds, providing it for the GNU Project, which at the time did not have a kernel. Independently of this, further development was carried out on the GNU kernel. The GNU operating system is available to all interested parties free of charge as open source. It can be used for all applications and the user who has access to the source code can change it for his applications.