Difference between UNIX and LINUX

[RH-Calvin]

If you add the GNU userland tools, you get GNU/Linux, which is a UNIX-like operating system. Along with GNU/Linux, there are several other UNIX-like operating systems, including the BSDs, (Open)Solaris, and some commercial operating systems (HP-UX and AIX are still kicking, IRIX hasn't seen activity since 2006).