#!/bin/sh

# Substitute pattern in files
# By Michalis Faloutsos

if [ $# -eq 0 ]
then
	echo "Usage  : sub oldPattern newPattern files"
	echo "Example: sub john John Documnet.txt"
	exit 1
fi

toChange=$1
toBecome=$2
# ignore the first two arguments
shift    
shift
myfile=$*

#echo FILES: $myfile

for file in $myfile
do
# sed is a file editing tool
  sed "s/$toChange/$toBecome/g" $myfile
done