There is an need of kill one port is already in use.
The command is :
lsof -i:8000
There will be a list of:
command pid user fd type device size/off node name
The command shows which program is now use the port, the pid is process id, the user is username of the operator, the fd is something I don't konw, the type is protecol of internet, the device is sth I don't know, the name is the application's URL.
So, what we need to do to kill the process uses port 8000 is to type the command:
kill pid(the process id showed by the command we type last)
