How to lock unable to lock database error in Arch Linux

If pacman intrupted the  /var/lib/pacman/db.lck error occured more as follows...

  error: failed to init transaction (unable to lock database)
if you're sure a package manager is not already
running, you can remove /var/lib/pacman/db.lck

Any one can correct it with rm command with sudo as following...

 sudo rm /var/lib/pacman/db.lck

and type your password
That's it