一、查看系统版本命令
1.查看内核版本命令
<1> cat /proc/version
<2>uname -r
<3>uname -a
2.查看linux版本命令
<1>lsb_release -a
注:这个命令适用于所有的linux，包括Redhat、SuSE、Debian等发行版。
<2>cat /etc/issue
<3>cat /etc/redhat-release
注:这种方式下可以直接看到具体的版本号。
<4>rpm -q redhat-release
注:这种方式下可看到一个所谓的release号
这个release号和实际的版本之间存在一定的对应关系，如下：
redhat-release-3AS-1 -> Redhat Enterprise Linux AS 3
redhat-release-3AS-7.4 -> Redhat Enterprise Linux AS 3 Update 4
redhat-release-4AS-2 -> Redhat Enterprise Linux AS 4
redhat-release-4AS-2.4 -> Redhat Enterprise Linux AS 4 Update 1
redhat-release-4AS-3 -> Redhat Enterprise Linux AS 4 Update 2
redhat-release-4AS-4.1 -> Redhat Enterprise Linux AS 4 Update 3
redhat-release-4AS-5.5 -> Redhat Enterprise Linux AS 4 Update 4
2.只对Red hat linux有效的两种方法：
<1> file /bin/bash
<2>file /bin/cat
