how to see all port open on ubuntu 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: ubuntu open port

sudo ufw allow 1191/tcp

Example 4: check if port is running in ubuntu

# Any of the following
sudo lsof -i -P -n | grep LISTEN
sudo netstat -tulpn | grep LISTEN
sudo lsof -i:22 # Port
sudo nmap -sTU -O IP-address-Here