How do I release ports which are being held by a notebook server after it has been stopped? -

i'm starting jupyter notebook server on aws instance (redhat linux server) connect on https. in config file have should on port 9999. when stop , restart process ctrl-c, port not being released, shown below.

[user@ip-xxx-xx-xx-xxx notebook]$ [i 08:39:27.901 notebookapp] port 9999 in use, trying random port. [i 08:39:27.901 notebookapp] port 10000 in use, trying random port. [i 08:39:27.902 notebookapp] port 10001 in use, trying random port. [i 08:39:27.905 notebookapp] serving notebooks local directory: /home/user/docs/notebook [i 08:39:27.905 notebookapp] 0 active kernels [i 08:39:27.905 notebookapp] jupyter notebook running at: https://[all ip addresses on system]:10002/ [i 08:39:27.905 notebookapp] use control-c stop server , shut down kernels (twice skip confirmation). 

as aside, "random ports" don't random me.

sometimes stop command of service doesn't return error , deletes pid file of process, not terminate process itself.

you can check if process still running running stop command , either

ps aux | grep -i notebook 

or

netstat -tlnp | grep <portnumber> 

as stated can either kill process manually, or fix stop script (usually /etc/init.d/servicename+d). reason process not killed (not always) linked permissions owned user executing command