Reusing gpg-agent across login sessions (bashrc) on a headless server

gpg_agent_daemon_bashrc.sh

# Run:
#  sudo apt-get install gnupg-agent
#  sudo apt-get install pinentry-curses
# Edit:
#  $HOME/.gnupg/gpg-agent.conf: 
#   pinentry-program /usr/bin/pinentry-curses
#   default-cache-ttl 28800000
#   max-cache-ttl 28800000
# Edit:
#  $HOME/.subversion/config:
#   password-stores = gpg-agent
if [ -f /usr/bin/gpg-agent ]; then
       export GPG_TTY=`tty`
       GPG_AGENT_INFO_FILE="$HOME/.gpg-agent-info"
       if [ -f "$GPG_AGENT_INFO_FILE" ]; then
               source "$GPG_AGENT_INFO_FILE"
               eval $(cat $GPG_AGENT_INFO_FILE)
               eval $(cut -d= -f 1 < $GPG_AGENT_INFO_FILE | xargs echo export)
       fi
       gpg-connect-agent /bye &>/dev/null
       if [ ! $? -eq 0 ]; then
               pkill -x gpg-agent -u $UID
               gpg-agent --allow-preset-passphrase --daemon --write-env-file="$GPG_AGENT_INFO_FILE" >/dev/null
               source "$GPG_AGENT_INFO_FILE"
               eval $(cat $GPG_AGENT_INFO_FILE)
               eval $(cut -d= -f 1 < $GPG_AGENT_INFO_FILE | xargs echo export)
       fi
fi