一、查看Linux系统版本的命令（3种方法）
1、适用于所有的Linux发行版
cat /etc/issue
[root@S-CentOS home]# cat /etc/issue
CentOS release 6.5 (Final)
Kernel \r on an \m
2、只适合Redhat系的Linux：
cat /etc/redhat-release
[root@S-CentOS home]# cat /etc/redhat-release
CentOS release 6.5 (Final)
3、列出所有版本信息：
lsb_release -a
[root@S-CentOS ~]# lsb_release -a
LSB Version: :base-4.0-amd64:base-4.0-noarch:core-4.0-amd64:core-4.0-noarch:graphics-4.0-amd64:graphics-4.0-noarch:printing-4.0-amd64:printing-4.0-noarch
Distributor ID: CentOS
Description: CentOS release 6.5 (Final)
Release: 6.5
Codename: Final
lsb_release命令安装：
yum -y install redhat-lsb
二、查看Linux内核版本：
1、cat /proc/version
[root@S-CentOS home]# cat /proc/version
Linux version 2.6.32-431.el6.x86_64 (mockbuild@c6b8.bsys.dev.centos.org) (gcc version 4.4.7 20120313 (Red Hat 4.4.7-4) (GCC) ) #1 SMP Fri Nov 22 03:15:09 UTC 2017
2、uname -a
[root@S-CentOS home]# uname -a
Linux S-CentOS 2.6.32-431.el6.x86_64 #1 SMP Fri Nov 22 03:15:09 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux