Automatic Stop AWS EC2 Bastion Instance each hour if no SSH connection established

stopinator.sh

#!/bin/bash
# Copyright (c) 2018, Pierre Tomasina

INSTANCE_ID=`curl -s http://169.254.169.254/latest/meta-data/instance-id`
EC2_REGION=`curl -s http://169.254.169.254/latest/meta-data/placement/availability-zone | rev | cut -c 2- | rev`
SSH_RUNNING=`netstat -nap | grep ESTABLISHED | grep sshd`

uptimeMore60min=`cat /proc/uptime | awk '{print $1/60" > 60"}' | bc -l`

if [ 0 -eq $uptimeMore60min ];then
  echo "Less then hour, do not stop instance"
  exit 0
fi

if [ -z "$SSH_RUNNING" ];then
  echo "stopping the instance $INSTANCE_ID in $EC2_REGION"
  aws ec2 stop-instances --instance-ids $INSTANCE_ID --region $EC2_REGION
fi