Rename a group of files

rename_files.sh

#!/bin/bash
# Renames a group of files
counter=0
filename=$1
context=$2
ext=$3

if [ $# -ne 0 ]
then
	if [ -z "${ext}" ]
	then
		ext=${context}
	fi
	for file in *.${context}
	do
		counter=$((counter+1))
		mv "${file}" ${filename}_${counter}.${ext}
	done
		# echo "Filename: ${filename}, Context: ${context}, Ext: ${ext}"
else
	echo "Usage: rename_files <base_file_name> <context> [extension]"
fi