Basic firewall-cmd commands
For reference, these are some of the most used firewall-cmd I use on CentOS 7.
firewall-cmd --list-all-zones firewall-cmd --zone=internal --change-interface=eth1 firewall-cmd --zone=internal --add-port=80/tcp --permanent firewall-cmd --zone=internal --add-protocol=vrrp --permanent firewall-cmd --reload firewall-cmd --list-ports --zone=internal firewall-cmd --list-proto --zone=internal
For a complete list got to the official documentation.