#!/bin/bash

proc printHelp
{
  echo "Usage: $0 -f find -r replace FILES_TO_RENAME*"
  echo -e "\t-f The text to find in the filename"
  echo -e "\t-r The text used to replace with in the filename"
  exit 1
}

while getopts "f:r:" opt {
  match $opt {
    with r  setglobal replace = $OPTARG    
    with f  setglobal fnd = $OPTARG        
    with ?  printHelp            
  }
}

shift $shExpr(' $OPTIND - 1 ')

if test -z $replace || test -z $fnd
{
  echo "Need a string to find and a string to replace";
  printHelp
}

for i in [$ifsjoin(Argv)]
{
  setglobal newname = $[echo $i | sed "s/$fnd/$replace/]
  mv $i $newname
  echo "Renamed file $i to $newname"
}