how to get the Linux OS version

how to get the Linux OS version...

To get the Linux OS version just follow any one method

1) Read the /etc/redhat-release file

[root@localhost ~]# cat /etc/redhat-release
Red Hat Enterprise Linux Server release 5.5 (Tikanga)
[root@localhost ~]#
2) use lsb_release command

[root@localhost ~]# lsb_release -a
LSB Version:    :core-3.1-amd64:core-3.1-ia32:core-3.1-noarch:graphics-3.1-amd64:graphics-3.1-ia32:graphics-3.1-noarch
Distributor ID: RedHatEnterpriseServer
Description:    Red Hat Enterprise Linux Server release 5.5 (Tikanga)
Release:        5.5
Codename:       Tikanga
[root@localhost ~]#
3) by  /etc/issue file

[root@localhost ~]# cat /etc/issue
Red Hat Enterprise Linux Server release 5.5 (Tikanga)
Kernel \r on an \m
[root@localhost ~]#

Here OS version is RHEL 5.5

First option is best to get correct information : # cat /etc/redhat-release