pr20_filelowercase.sh

#!/bin/bash 
file=$1
if [ $# -eq 0 ]
then
	echo "$(basename $0) file"
	exit 1
fi
if [ ! $file ]
then
	echo "$file not a file"
	exit 2
fi
lowercase=$(echo $file | tr '[A-Z]' '[a-z]'])
if [ -f $lowercase ]
then
	echo "Error - File already exists!"
	exit 3
fi
/bin/mv $file $lowercase