How do I lock the screen after resuming from hibernation?

I've been able to successfully hibernate and resume my Ubuntu 12.04 Desktop PC using procedure that I've documented in this answer. However, I now have a problem that whenever the PC resumes, it does not locks the screen.

How can I lock the screen after the system resumes back from hibernation?

I have added an alias into ~/.bashrc file

alias hibernate='sudo echo "Hibernating..."; gnome-screensaver-command -l; sudo pm-hibernate;'

So that it locks the screen before hibernating.

I've been able to workaround this issue, by using the following command

sudo pm-hibernate; gnome-screensaver-command -l

Do note that, you should run this as a normal user and not as root user for locking to work, because by default in Ubuntu, there is no password for the root user so after resume, lock-screen can be unlocked by simply shaking the mouse.

i have another workaround. i copied this from /etc/acpi/sleep.sh to /etc/acpi/hibernate.sh just before pm-hibernate

if [ x$LOCK_SCREEN = xtrue ]; then
    if pidof xscreensaver > /dev/null; then
    for x in /tmp/.X11-unix/*; do
        displaynum=`echo $x | sed s#/tmp/.X11-unix/X##`
        getXuser;
        if [ x"$XAUTHORITY" != x"" ]; then
        export DISPLAY=":$displaynum"
        . /usr/share/acpi-support/screenblank
        fi
    done
    fi
fi

now i can hibernate with lock from power menu or a sleep button