#!/bin/ksh
# changeword version 1.0

# This script takes 3 argument:
# changeword <from_word> <to_word> <file>
# This script replaces occurences of from_word to to_word

if [ $# -lt "3" ]
then
	echo Usage: changeword from_word to_word file
	exit 1
fi

for x
do
if [ $x != "changeword" ] && [ $x != $1 ] && [ $x != $2 ]
then
	echo "changing $x: \c"

# Make sure file is not empty
	if test -s $x
	then
		sed "/$1/s//$2/g" $x > $x.new

# Check outputed sed file
		if test -s $x.new
		then
			if cmp -s $x $x.new
			then
				echo "file not changed: \c"
			else
				cp $x.new $x
			fi		
			echo "done"
		else
			echo "Sed produced an empty file."
		fi
	else
		echo $x" is empty or is not a file."
	fi
	rm $x.new
fi
done