Okay, I have a script right now that is made to search through a file and replace certain strings with a new one. The format to execute is "/subst <replacethis> <withthis> <filename>" and it only updates the file IF changes are made (in order to preserve the time it was made/last modified). I have this working 100% right now, but the next step is to edit the script so that it is possible for users to do "/subst <replacethis> <withthis> <filename> <filename2> <filename3> <filenamex>" as high as they want. If anyone can point me in the right direction of methods to do this or simply fix it for me, I would be very greatful.

Here is my current script:

#!/bin/bash

replacethis=$1
withthis=$2
file=$3

sed -e "s+$replacethis+$withthis+g" $file > $file.bak

cmp $file $file.bak > /dev/null
if [ $? -eq 0 ]
then
  echo "Files are the same, nothing was replaced."
  rm $file.bak
else  
  mv $file.bak $file
fi