path: rear_2.9+dfsg-3/usr/sbin/rear
    #   ...  2991 ... /usr/bin/ssh-agent /usr/bin/gpg-agent --sh --daemon --keep-display /etc/X11/xinit/xinitrc
    #   ... 18219 ... /usr/bin/ssh-agent -D -a /run/user/1000/keyring/.ssh
    #   # pidof -x "ssh-agent"
    #   18219 2991
    #   # pidof -x "/usr/bin/ssh-agent"