Linux Administration Cookbook

CentOS

We can determine the version of our CentOS installation by printing the contents of the centos-release file, as follows:

$ cat /etc/centos-releaseCentOS Linux release 7.5.1804 (Core)

Here's a fun fact (among a certain type of people): if you cat the contents of redhat-release on your box, you'll get the same information, due to the fact that CentOS and Red Hat systems are so closely aligned:

$ cat /etc/redhat-release CentOS Linux release 7.5.1804 (Core)

cat (derived from concatenate) is a program that was historically used to print the contents of multiple files to standard out.

Likewise, system-release is a symbolic link to centos-release:

$ cat /etc/system-releaseCentOS Linux release 7.5.1804 (Core)

If you wanted more detailed ...