1. $ lsof -P -i -n | cut -f 1 -d " "| uniq | tail -n +2
2. $ slof -P -i -n
3. $ ss -p
a. ss -p | cat
b. ss -p | grep STA
c. ss -p | cut -f2 -sd\"
d. ss -p | grep STA | cut -f2 -d\"
4. $ netstat -lantp | grep -i stab | awk -F/ '{print $2}' | sort | uniq
5. $ netstat -lantp | grep -i establ | awk -F/ '{print $2}' | sort | uniq
6. $ netstat -lantp | grep -i establ | awk -F/ '{print $2}' | uniq | sort

Food for thought.