Update WHM/cPanel Hostname in Terminal

The Linux hostname command is not enough, as it won’t change HELLO for Exim, or reset the SSL certificates.

The good hostname script is:

/usr/local/cpanel/bin/set_hostname 

The hostname need to be FQDN, in the format, for example:

/usr/local/cpanel/bin/set_hostname host.exampledomain.com