#!/bin/sh
#
# $0 new old
# Replaces old with new if they differ. old is saved as old.bak
if cmp -s "$1" "$2"; then
echo "$2 is unchanged"
rm "$1"
else
echo "Replacing $2 by $1"
if [ -f "$2" ]; then
mv "$2" "$2.bak"
fi
mv "$1" "$2"