rename.sh

#!/bin/bash

if ( test "$1" == "" ); then 
    echo "prefix of each image is empty.";
    echo "Do you want to continue?";
    read response;
    if (( ("$response" != "y") || ("$response" != "Y")  )); then
        exit 1;
    fi
fi

COUNTER=0

for file in *.JPG
do
    mv "$file" "$1$COUNTER.JPG"
    let COUNTER=COUNTER+1
done