Check out the book information and briefly record the origins of Linux
Linux before, the world of Unix, but Unix is not free, and very expensive.
In 1983, Richard Stallman launched the GNU program-all software must be free to use, freely change, and distribute freely. GPL-the software release must publish the source code, which can be freely used and changed by the person, but to publish the change code after the change.
In 1991, Finnish university student Linus Tovacs (Linus Benedict Torvalds) developed Linux.
Linux joined the GNU program in 1994 and was released under the GPL agreement.
Release version
1993 Debian, Branch 2004 Ubuntu.
1993 Slackware, Branch 1994 SuSE.
1994 redhat,2002 Redhat Enterprise (RHEL) original Redhat is not released.
2003 CentOS, with Rhel source code compiled, some places slightly changed, 2014 was Redhat acquired.
Linux development history, several representative Linux distributions