查看系统版本：
cat /etc/redhat-release（/etc/centos-release）
// 或者
rpm -q centos-release
[root@56 ~]# cat /etc/redhat-release
CentOS Linux release 7.XXX (Core)
[root@56 ~]# rpm -q centos-release
centos-release-7-XXX.centos.x86_64
升级：
yum clean all
yum update
// 或者
yum upgrade
服务器漏洞修复持续更新中
https://blog.csdn.net/weixin_44006570/article/details/107158273
.