UTSL

from Jargon File (4.4.4, 14 Aug 2003)

UTSL
 //, n.

   [Unix] On-line acronym for `Use the Source, Luke' (a pun on Obi-Wan
   Kenobi's "Use the Force, Luke!" in Star Wars) -- analogous to {RTFS}
   (sense 1), but more polite. This is a common way of suggesting that
   someone would be better off reading the source code that supports
   whatever feature is causing confusion, rather than making yet another
   futile pass through the manuals, or broadcasting questions on Usenet
   that haven't attracted {wizard}s to answer them.

   Once upon a time in {elder days}, everyone running Unix had source.
   After 1978, AT&T's policy tightened up, so this objurgation was in
   theory appropriately directed only at associates of some outfit with a
   Unix source license. In practice, bootlegs of Unix source code (made
   precisely for reference purposes) were so ubiquitous that one could
   utter it at almost anyone on the network without concern.

   Nowadays, free Unix clones have become widely enough distributed that
   anyone can read source legally. The most widely distributed is
   certainly Linux, with variants of the NET/2 and 4.4BSD distributions
   running second. Cheap commercial Unixes with source such as BSD/OS are
   accelerating this trend.

from The Free On-line Dictionary of Computing (8 July 2008)

UTSL

   <humour> {Use the Source Luke}

   [{Jargon File}]

   (1996-01-02)

from V.E.R.A. -- Virtual Entity of Relevant Acronyms (June 2006)

UTSL
       Use The Source, Luke (telecommunication, Usenet, IRC)