Display the system's DNS domain name.
The dnsdomainname command is used to show the domain name part of the system's fully qualified domain name (FQDN).
dnsdomainname (options)
-v Verbose mode, output detailed information about the command execution.
[root@AY1307311912260196fcZ ~]# dnsdomainname -v
gethostname()=`AY1307311912260196fcZ'
Resolving `AY1307311912260196fcZ' ...
Result: h_name=`AY1307311912260196fcZ'
Result: h_addr_list=`10.160.7.81'