There's a dozen ways to pass NULL argv[i]'s to exec. The code must check each argv[i], including argv[0], for NULL and print something other than argv[i] in that case. See man execve(2) for a simple way to create lots and lots of NULL argv[i]s. -- Peter --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .