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

You can use netcat command as well

[location of netcat]/netcat -zv [ip] [port]

or

nc -zv [ip] [port]

-z – sets nc to simply scan for listening daemons, without actually sending any data to them.
-v – enables verbose mode.