The Jargon File (version 4.4.7, 29 Dec 2003):

glark
 /glark/, vt.

    To figure something out from context. ?The System III manuals are pretty
    poor, but you can generally glark the meaning from context.? Interestingly,
    the word was originally ?glork?; the context was ?This gubblick contains
    many nonsklarkish English flutzpahs, but the overall pluggandisp can be
    glorked [sic] from context? (David Moser, quoted by Douglas Hofstadter in
    his Metamagical Themas column in the January 1981 Scientific American). It
    is conjectured that hacker usage mutated the verb to ?glark? because glork
     was already an established jargon term (some hackers do report using the
    original term). Compare grok, zen.


The Free On-line Dictionary of Computing (30 December 2018):

glark

   /glark/ To figure something out from context.  "The System III
   manuals are pretty poor, but you can generally glark the
   meaning from context."  Interestingly, the word was originally
   "glork"; the context was "This gubblick contains many
   nonsklarkish English flutzpahs, but the overall pluggandisp
   can be glorked [sic] from context" (David Moser, quoted by
   Douglas Hofstadter in his "Metamagical Themas" column in the
   January 1981 "Scientific American").  It is conjectured that
   hackish usage mutated the verb to "glark" because glork was
   already an established jargon term.

   Compare grok, zen.

   [Jargon File]