Find out which version of Centos/Red Hat/Fedora you are running

bojan@veprina:~$ lsb_release -a

LSB Version:    :base-4.0-ia32:base-4.0-noarch:core-4.0-ia32:core-4.0-noarch:graphics-4.0-ia32:graphics-4.0-noarch:printing-4.0-ia32:printing-4.0-noarch
Distributor ID:    CentOS
Description:    CentOS release 6.4 (Final)
Release:    6.4
Codename:    Final