How to check if a port is open on a server?

I wanted to check if the service I am trying to access on a server is actually listening on the port I am hitting. I tried to look for a ping variant which could tell me if the port is listening and required service is up and running.

Found nmap command as answer.

nmap -p 80 google.com

Starting Nmap 6.40 ( http://nmap.org ) at 2016-03-02 16:05 IST
Nmap scan report for google.com (216.58.197.78)
Host is up (0.050s latency).
rDNS record for 216.58.197.78: maa03s21-in-f14.1e100.net
PORT STATE SERVICE
80/tcp open http

It checks the port state and also what service is listening at the port.