Hostname_configuration

I am looking for information on the proper way to change my hostname after
install.  I needed the network settings to obtain ip address automatically
and the install wouldn't let me declare a hostname but also have the system
obtain other network settings automatically.  So now I have
localhost.localdomain which I need to change:  what is the proper way to do
this?  I noticed that if I use the hostname command, the hostname changes in
the terminal but this change is not reflected in /etc/hosts file or in the
dns configuration settings.  Advice is much appreciated - thanks in advance.