Let the Sunshine In: Software support engineer in Tokyo

I wanted to check whether our business critical web server is up in every 6 hours.

First I thought I run ping every 6 hours via 'cron'. But I want to ping more often once server is detected down and until it comes back up.

So, I came up with this self registering 'at' script. This begins pinging the server in incremental backoff intervals once it's detected down. Starts at 1 minute, and then 2 minutes. 3,4,5... If you replace "+1" wit "*2", it will do exponential backoff. 1,2,4,8,16...

$ cat ~/misc/myServerPing.at
# THISFILE should be full path or relative from $HOME
# Run this in bash by ". {this file}"
THISFILE=misc/myServerPing.at
INTERVAL=1

curl --silent --connect-timeout 8 http://ourserver.sun.com | grep "Our critical page" > /dev/null

if [ $? -ne 0 ]; then
  date | mailx -s "Failed ping to ourserver" my.mail.address@sun.com
  sed "s/^\(INTERVAL=\)[1-9]*$/\\1$(($INTERVAL+1))/" $THISFILE | at now + $INTERVAL minutes > /dev/null 2>&1
else
  at now + 360 minutes < $THISFILE > /dev/null 2>&1
fi