How to check whether port is open or not in Linux

Syntax:

echo > /dev/tcp/[host]/[port] && echo "Port is open"
echo > /dev/udp/[host]/[port] && echo "Port is open"

Example:

echo > /dev/tcp/172.16.11.45/7091 && echo "Port is open"

 echo > /dev/tcp/172.16.11.45/7091 && echo "Port is open"