• BackTrack 5 r1

 #!/bin/bash
 DEVICE="eth0"
 EVENT="/usr/bin/truecrypt --text --dismount --force > /dev/null 2>&1"
 CNT=0
 while true ; do
   if ! ethtool $DEVICE 2> /dev/null | grep "Link detected: yes" 1> /dev/null ; then
     (( CNT++ ))
   else
     CNT=0
   fi
   if [[|$CNT -gt 6 ]] ; then $EVENT ; fi
   sleep 10
 done
 exit 0