Keeps the details of the auth agent in a file, tries to load it, checks if that agent is still running, and if not, starts another one.

run_ssh_agent.sh

#!/bin/bash

SSH_ENV="$HOME/.ssh/environment"

function start_agent {
    echo "Initialising new SSH agent..."
    (umask 066; /usr/bin/ssh-agent > "${SSH_ENV}")
    . "${SSH_ENV}" > /dev/null
    /usr/bin/ssh-add;
}

if [ -f "${SSH_ENV}" ]; then
    . "${SSH_ENV}" > /dev/null
    ps -ef | grep ${SSH_AGENT_PID} | grep ssh-agent$ > /dev/null || {
        start_agent;
    }
else
    start_agent;
fi