!/bin/sh
blocks=0
blocks=`df -k /opt/mysql | awk '{if(length($5)<4)
                                 {print substr($5,1,2)}}'`
echo "The database capacity is at" $blocks"%"
echo "Blocks size is "$blocks
if [ $blocks -gt 15 ]
 then
  *This is where I need the message*
elif [ $blocks -gt 10 ]
 then
  *This is where I need the message*
else
  *This is where I need the message*

fi