Number one, check the release version

# redhat7 and centos7 view method

Methods: [root] # cat/etc/redhat - release

[root] # cat/etc/centos - release

# redhat6 and centos6 view method

Method 1: [root] # lsb_release - a

Method 2: [root] # cat/etc/redhat - release

[root] # cat/etc/centos - release

Method 3: [root] # cat/etc/issue

Second, check the kernel version

Method 1: [root] # uname -a (recommended)

Method 2: [root] # cat/proc/version