#!/bin/sh -u
# a counting loop adjusted to range from -20 to +20, parabola output
#
# NOTE: This script fragment is incomplete - it does not follow all
# the script guidelines set out in "script_style.txt".  It also
# contains many "Instructor-Style" comments that you must not use in
# your own scripts.  See script_style.txt for details.
#
# -IAN! idallen@idallen.ca

PATH=/bin:/usr/bin ; export PATH
LC_COLLATE=C ; export LC_COLLATE
LANG=C ; export LANG
umask 022

let num=20
let y=-num
while [ $y -le $num ] ; do
    let x=y*y
    echo "y is $y, x is $x"
    let y=y+1
    sleep 0.1
done