(List
  (Com {[LIT_CHARS echo]} {[SQ <LIT_CHARS "--- pgrphack insists on an argument">]}  )
  (Com {[LIT_CHARS pgrphack]}  )
  (Com {[LIT_CHARS echo]} {[VarSub ?]}  )
  (Com {[LIT_CHARS echo]} {[SQ <LIT_CHARS "--- pgrphack complains if it cannot run program">]}  )
  (Com {[LIT_CHARS pgrphack]} {[LIT_CHARS ./nonexistent]}  )
  (Com {[LIT_CHARS echo]} {[VarSub ?]}  )
  (Com {[LIT_CHARS echo]} {[SQ <LIT_CHARS "--- pgrphack runs a program">]}  )
  (Com {[LIT_CHARS pgrphack]} {[LIT_CHARS echo]} {[LIT_CHARS ok]}  )
  (Com {[LIT_CHARS echo]} {[VarSub ?]}  )
)