What is the use of dig command ?

dig is used to get the information from a website (DNS lookup)

dig = Domain Info Groper

$ dig google.com

....

->>HEADER<<- opcode: QUERY, status: NOERROR, id: 62863

QUESTION SECTION : Your input here

....

ANSWER SECTION : Answer received from the DNS

....


AUTHORITY SECTION : DNS (available) name servers that have authority to respond to this query

....


ADDITIONAL SECTION : Address of name servers listed in the AUTHORITY SECTION

....



Stats SECTION : Statistics including how much time it took to execute this query

 
 
View short output - just the IP address of a web site
 
$ dig redhat.com +short
209.132.183.81

Using DNS server

By default, dig command uses the DNS servers defined in your /etc/resolv.conf file.

$ dig google.com

If you want to use a different DNS server to perform the query, use @dnsserver

Example

$ dig google.com @ns1.google.com

It will use ns1.google.com as the DNS server to get the answer 

instead of using the DNS servers from the /etc/resolv.conf file.