DNS lookup utility.
# To lookup the IP(s) associated with a hostname (A records):
dig +short <example.com>
# To get a detailed answer for a given domain (A records):
dig +noall +answer <example.com>
# To query a specific DNS record type associated with a given domain name:
dig +short <example.com> <A|MX|TXT|CNAME|NS>
# To get all types of records for a given domain name:
dig <example.com> ANY
# To specify an alternate DNS server to query:
dig @<8.8.8.8> <example.com>
# To perform a reverse DNS lookup on an IP address (PTR record):
dig -x <8.8.8.8>
# To find authoritative name servers for the zone and display SOA records:
dig +nssearch <example.com>
# To perform iterative queries and display the entire trace path to resolve a domain name:
dig +trace <example.com>