Using an ssh-agent in a script

ssh_agent.sh

#!/bin/bash
 
tempfile=/tmp/ssh-agent.test
 
#Check for an existing ssh-agent
if [ -e $tempfile ]
then
    echo "Examining old ssh-agent"
    . $tempfile
fi
 
#See if the agent is still working
ssh-add -l > /dev/null
 
#If it's not working yet, just start a new one.
if [ $? != 0 ]
then
    echo "Old ssh-agent is dead..creating new agent."
 
    #Create a new ssh-agent if needed
    ssh-agent -s > $tempfile
    . $tempfile
 
    #Add the key
    ssh-add
fi    
 
#Show the user which keys are being used.
ssh-add -l