Linux distributions -- Mapping kernel version to release

There are a plenty of linux distribution and people are blinded . Best way to take call is using command uname --all

Example :

For  RHEL 5


Linux hostname 2.6.18-274.12.1.el5PAE #1 SMP Tue Nov 8 21:58:59 EST 2011 i686 i686 i386 GNU/Linux

For RHEL 6

Linux hostname 2.6.32-220.el6.x86_64 #1 SMP Wed Nov 9 08:03:13 EST 2011 x86_64 x86_64 x86_64 GNU/Linux