shut down when ssh idle for more than 5 minutes

close.sh

#!/bin/bash
# docker run --name=close --network=host --privileged --restart=always -d close:v0.0.1

while true; do
  if [ -f dump ]; then
    rm dump
  fi

  timeout 5m tcpdump -nn tcp and port 22 and greater 44 -w dump

  line_count=$(wc -l < dump)

  if [ $line_count -gt 0 ]; then
    rm dump
  else
    rm dump
    shutdown -h now
  fi
done