The dig (Domain Information Groper) is a very useful utilities for querying DNS name servers.
List of useful dig commands.
To check dig version
# dig -v
To get help page
# dig -h
To query a single host (domain) without any additional options
# dig gitlab.com
To get a short answer to your query
# dig gitlab.com +short
To turn off all the results and then turn on only the answer section
# dig gitlab.com +noall +answer
To specify a name server ( By default use /etc/resolv.conf file if no name server is specified)
# dig gitlab.com @8.8.8.8
To query based on record type ( any, a , cname, txt, mx and ns record )
# dig +nocmd gitlab.com any +noall +answer
# dig +nocmd gitlab.com a +noall +answer
#dig +nocmd gitlab.com cname +noall +answer
#dig +nocmd gitlab.com txt +noall +answer
#dig +nocmd gitlab.com mx +noall +answer
#dig +nocmd gitlab.com ns +noall +answer
To query reverse lookup
#dig -x 95.216.246.23 +noall +answer
To query a large number of domains ( i.e from a file )
#dig -f test.txt +short
