Linux is a free and open-source monolithic kernel created by Linus Torvalds in 1991. Unlike BSD Flavours(FreeBSD , OpenBSD and NetBSD Linux is not a full operating system; it is only a kernel and is packaged with other tools and utilities into a "distribution" or distro. Examples of these distros are Debian , Fedora , Boop!_OS and risiOS . Linux is licensed under GNU GPL-2 .