#!/bin/ksh
#Change the text representation of a GIF from color to
#black and white.  Compute the average of the red, green,
#and blue components of each pixel.

awk '
	NR <= 3 {print $0}
	NR >  3 {a = int(($1 + $2 + $3) / 3); print a, a, a}
'

exit 0