pascal + unix commands?

Is there any way for me to run unix commands through a pascal program? I'm
using PC (sgi's pascal compiler), on an IRIX system. Anyone have an idea?

   = The wise man can pick up a grain of sand and  =
   = envision a whole universe.  But the stupid    =
   = man will just lay down on some seaweed and    =
   = roll around until he's completely draped in   =
   = it.  Then he'll stand up and go, "Hey, I'm    =
   =                  Vine Man."                   =