Old way:
Examine list of DNS servers in /etc/resolv.conf:

$ cat /etc/resolv.conf

– – –

New way:
May not work on newer Linuxes since resolving may be setup via (not only DNS, but also) various other services: DDNS, LDAP, Avahi, Bonjour, ZeroConf and God knows what else.

So…

To check up […]