On Tue, 24 Nov 2015, Siva Prasad Nath wrote:
auto eth0 iface eth0 inet static address 192.168.50.2 netmask 255.255.255.0
That's a configuration for a Linux system running Debian or Ubuntu Linux. CentOS (the topic of this mailing list) and other distributions in the Red Hat family use a completely different syntax for network configuration.
If you're completely new to Linux, I'd suggest you find a local Linux user group and get some hands-on help.