#!/bin/sh

IFS='
'

if [ "$1" ] ; then
    flist=$(find . -type f -iname "*.$1")
else
    flist=$(find . -type f)
fi

for i in $flist ; do
    fname=$(basename $i)
    dir=$(dirname $i)

    fname_new=$(echo $fname | tr '[A-Z]' '[a-z]')

    if [ "$fname" != "$fname_new" ] ; then
    	echo mv "$i" "$dir/$fname_new"
    	mv "$i" "$dir/$fname_new"
    fi
done