[root@zhtest1 ~]# cat /etc/issue
\S
Kernel \r on an \m
[root@zhtest1 ~]# lsb_release -a
-bash: lsb_release: command not found
[root@zhtest1 ~]# cat /proc/version
Linux version 4.19.12-1.el7.elrepo.x86_64 (mockbuild@Build64R7) (gcc version 4.8.5 20150623 (Red Hat 4.8.5-36) (GCC)) #1 SMP Fri Dec 21 11:06:36 EST 2018
[root@zhtest1 ~]# cat /etc/redhat-release
CentOS Linux release 7.9.2009 (Core)