* Unix is the 1st operating system came in word in 1917's.
* Linux is one of the flavor among Solaris ,HP-unix and AIX .
* Linux is open source software. it means it can be freely available .
* Linux is the Linux kernel, an operating System kernel first released on October 5, 1991 by Linus Torvalds.
*Most of the companies are using Linux instead Windows .
*Linux Kernel is designed in such a manner that Virus is wont effect to it .
* From Security perspective, In Linux we have IP Tables, which is inbuilt firewall.
* In Linux systems we have file level security which provides SELinux.
4for more deeper about Linux please refer https://en.wikipedia.org/wiki/Linux