porta grátis no Linux
netstat -tulnap // list all ports and processes
netstat -anp|grep "port_number" // show port details
sudo fuser -k Port_Number/tcp // free the port needed
# or
lsof -n -i :'port-number' | grep LISTEN // get port details
# sample response: java 4744 (PID) test 364u IP0 asdasdasda 0t0 TCP *:port-number (LISTEN)
kill -9 PID // free port
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