Start ssh-agent properly and register keys

.bash_ssh

# 
# Start ssh-agent once only and register keys
#
# Usage : put this in .bashrc
# if [ -f ~/.bash_ssh ]; then
#    . ~/.bash_ssh
# fi
#
# http://stackoverflow.com/questions/18880024/start-ssh-agent-on-login#18915067
#
# useful commands :
# > eval $(ssh-agent -s)
# > ps -e | grep [s]sh-agent
# > ssh-add ~/.ssh/id_rsa
# > ssh-add -l

SSH_ENV="$HOME/.ssh/environment"

function start_agent {
    echo "Initialising new SSH agent..."
    /usr/bin/ssh-agent | sed 's/^echo/#echo/' > "${SSH_ENV}"
    echo succeeded
    chmod 600 "${SSH_ENV}"
    . "${SSH_ENV}" > /dev/null
    /usr/bin/ssh-add;
}

# Source SSH settings, if applicable

if [ -f "${SSH_ENV}" ]; then
    . "${SSH_ENV}" > /dev/null
    #ps ${SSH_AGENT_PID} doesn't work under cywgin
    ps -ef | grep ${SSH_AGENT_PID} | grep ssh-agent$ > /dev/null || {
        start_agent;
    }
else
    start_agent;
fi