"wport" - tells you ports that are LISTENing or checks a specific port

wport.sh

# add to ~/.zhsrc
# run source ~/.zshrc
# run w/ `wport` or `wport <port>`
function wport(){
    if [ "$1" = "help" ] || [ "$1" = "-h" ]; then
        echo "Usage: wport [port]"
        echo "Without a port argument, list all ports that are currently being listened to."
        echo
        echo "If a port is provided, list only the port that is being listened to."
        echo
        return
    fi
    if [ -z "$1" ]; then
        lsof -i -P | grep -e "LISTEN"
    else
        lsof -i -P | grep -e "$1.*LISTEN"
    fi
}