有以下命令可以查看：

# lsb_release -a
LSB Version:    :core-3.1-ia32:core-3.1-noarch:graphics-3.1-ia32:graphics-3.1-noarch
Distributor ID: CentOS
Description:    CentOS release 5.4 (Final)
Release:        5.4
Codename:       Final

这个命令适用于所有的linux，包括Redhat、SuSE、Debian等发行版。

root@MyMail ~ # uname
Linux
root@MyMail ~ # uname -r
2.6.18-164.el5

以下二种方法适用于RedHat,CentOS

root@MyMail ~ # cat /etc/redhat-release
CentOS release 5.4 (Final)

登录到linux执行rpm -q redhat-release 

#rpm -q redhat-release
或CentOS

root@MyMail ~ # rpm -q centos-release
centos-release-5-4.el5.centos.1

如何查看centos版本