TIL: Resolve the Public IP of a URL

The dig command is a utility for doing DNS lookups. You can run it with a URL argument to lookup the public IP for that domain.

$ dig joshbranchaud.com
; <<>> DiG 9.8.3-P1 <<>> joshbranchaud.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 62836
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;joshbranchaud.com.             IN      A
;; ANSWER SECTION:
joshbranchaud.com.      1800    IN      A       159.203.106.229
;; Query time: 50 msec
;; SERVER: 75.75.75.75#53(75.75.75.75)
;; WHEN: Sun Apr 14 12:34:52 2019
;; MSG SIZE  rcvd: 51

The output is a bit noisy, but if you parse down to the ANSWER SECTION, you'll see the IP address that it resolves to.

Alternatively, you can skip the noise and get right to the IP address by including the +short flag.

$ dig joshbranchaud.com +short
159.203.106.229

See man dig for more details.