[CentOS] firewalld management on a headless server

yum (CentOS/RedHat/Fedora)

By adding the Webmin repository and Jamie Cameron's key, it is
possible to install & maintain the latest Webmin/Usermin versions.

The following will install the latest Webmin version by adding the
webmin-repo and corresponding GPG key. Yum will resolve all the
necessary dependancies.

Just Cut&Paste the entire text below and hit enter/return:

(echo "[Webmin]
name=Webmin Distribution Neutral
baseurl=http://download.webmin.com/download/yum
enabled=1
gpgcheck=1
gpgkey=http://www.webmin.com/jcameron-key.asc" >/etc/yum.repos.d/webmin.repo;
yum -y install webmin)