Autostart SSH-agent and autoload private keys

bashrc

#
# Autostart SSH-agent and autoload all private keys in ~/.ssh directory
#
# How to use:
# - Place this scripts in ~/.bashrc
# - If ssh-agent is not filled by any private keys, passphrase prompts will show up for each private keys
#

# register ssh key
env=~/.ssh/agent.env

agent_load_env () { test -f "$env" && . "$env" >| /dev/null ; }

agent_start () {
    (umask 077; ssh-agent >| "$env")
    . "$env" >| /dev/null ; }

agent_load_env

# agent_run_state: 0=agent running w/ key; 1=agent w/o key; 2= agent not running
agent_run_state=$(ssh-add -l >| /dev/null 2>&1; echo $?)

if [ ! "$SSH_AUTH_SOCK" ] || [ $agent_run_state = 2 ]; then
    agent_start
    # this will load all private keys in ~/.ssh directory if agent not running
    find ~/.ssh/ -type f -exec grep -l "PRIVATE" {} \; | xargs ssh-add &> /dev/null
elif [ "$SSH_AUTH_SOCK" ] && [ $agent_run_state = 1 ]; then
    # this will load all private keys in ~/.ssh directory if agent is not filled with any private key
    find ~/.ssh/ -type f -exec grep -l "PRIVATE" {} \; | xargs ssh-add &> /dev/null
fi

unset env

# shortcut for accessing server1 via SSH
function sshsvr1() {
    ( ssh user@server1.example.com -p 2222 )
}

ssh_config

#
# Use dedicated private key only for certain host
#
# How to use:
# - Place this scrips in ~/.ssh/config
# - Everytime you access certain host via SSH, its dedicated private key will be used
#
# Example:
#   $ ssh user@server1.example.com -p 2222
#

# Global SSH configurations here will be applied to all hosts
IdentityFile ~/.ssh/github_rsa
IdentityFile ~/.ssh/server1_rsa
IdentityFile ~/.ssh/server2_rsa


Host github
    IdentityFile ~/.ssh/github_rsa

Host server1.example.com
    IdentityFile ~/.ssh/server1_rsa

Host server2.example.com
    IdentityFile ~/.ssh/server2_rsa

Can you provide a format of ~/.ssh/agent.env file?