sudo passwd root

After which you are prompted with a

Changing password for root.
New password:

Why the need for root? Surely, it’s a dangerous weapon and things can go awry easily, so only use it as a last resort. (I used it for hiding the couchdb account folder from the GUI.)

Hiding files and folders from the Finder:

chflags hidden filename

And show them again:

chflags nohidden filename

Run from Terminal: defaults write -g QCShowPrivatePatches 1 defaults write -g QCShowPrivatePatches 0