Jupyter notebook 'Connect to Jupyter' button not rendering

We don’t install netcat by default for security

https://listsprd.osu.edu/pipermail/ood-users/2018-October/000269.html

We added this function to our before script to validate the script:

port_used () {
local port="{1#*:}" sleep 2 netstat -nap 2>/dev/null | grep -q "0.0.0.0:{port} "
}