如何查看Linux操作系统版本？

如何查看Linux操作系统版本？

[root@localhost ~]# cat /etc/issue

CentOS release 6.3 (Final)

Kernel \r on an \m

[root@localhost ~]# cat /etc/redhat-release

CentOS release 6.3 (Final)

[root@localhost ~]# lsb_release -a

-bash: lsb_release: command not found

[root@DENGY ~]# lsb_release -a

LSB Version:   :core-3.1-ia32:core-3.1-noarch:graphics-3.1-ia32:graphics-3.1-noarch

Distributor ID: RedHatEnterpriseServer

Description:    Red Hat Enterprise Linux Server release 5.4(Tikanga)

Release:        5.4

Codename:       Tikanga

关于lsb_release -a和/etc/issue显示的发行版本号不同，原因只有一个：系统内核手动升级了。