linux check port in use code example

Example 1: linux how to see ports in use

# Any of the following
sudo lsof -i -P -n | grep LISTEN
sudo netstat -tulpn | grep LISTEN
sudo lsof -i:22 # see a specific port such as 22
sudo nmap -sTU -O IP-address-Here

Example 2: ubuntu check process on port

sudo lsof -i:22

Example 3: ports in use linux

# To see ports in use
sudo lsof -i -P -n | grep LISTEN 
sudo netstat -tulpn | grep LISTEN

Example 4: how to check list of open ports in linux

sudo lsof -i -P -n | grep LISTEN
sudo netstat -tulpn | grep LISTEN
sudo lsof -i:22 # see a specific port such as 22
sudo nmap -sTU -O IP-address-Here

Example 5: kill a port in ubuntu

kill -9 $(sudo lsof -t -i:'portName')
//Ex. if portname is 3000
//then we will execute "kill -9 $(sudo lsof -t -i:3000)"

Example 6: check what ports are open linux

## if you use linux
sudo ss -tulw