Command Line: Determine If Port Is Open & Listening

Asset.sh

netstat -an |grep 445 |grep LISTEN

# 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 quick:
# 1. lsof -i :445 (Takes seconds)
# 2. netstat -an |grep 445 |grep LISTEN (Takes seconds)
# 3. telnet (it doesn't return)
# 4. nmap, netcat are not available on the server
# 
# It will be nice to know of a way that doesn't enumerate first and greps after that.