Efficiently test if a port is open on Linux?

Question

From a bash script how can I quickly find out whether a port 445 is open/listening on a server.

I have tried a couple of options, but I want something q

Answer 1

nmap is the right tool. Simply use nmap example.com -p 80

You can use it from local or remote server. It also helps you identify if a firewall is blocking the access.