incantation
     n : a ritual recitation of words or sounds believed to have a
         magical effect [syn: {conjuration}]
Source: WordNet® 2.0

incantation n. Any particularly arbitrary or obscure command that one
   must mutter at a system to attain a desired result. Not used of
   passwords or other explicit security features. Especially used of tricks
   that are so poorly documented that they must be learned from a {wizard}.
   "This compiler normally locates initialized data in the data segment,
   but if you {mutter} the right incantation they will be forced into text
   space."


Source: The Jargon File