Bash script to download all the files from a given URI

ocw-download.sh

#!/bin/bash

# defaults
LINK=http://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-006-introduction-to-algorithms-spring-2008/lecture-notes/

NUMBER=5

FILE=lec$.pdf

throwErr()
{
        echo "Unknown Error Occurred!"
        echo "Usage: ./sdm -n=<number_of_iterations> -l=<link_of_directory> -f=<file_name_pattern>"
        exit 0
}

for i in "$@"
do
        case $i in
                -l=*|--link=*)
                        LINK="${i#*=}"
                        shift
                        ;;
                -n=*|--number=*)
                        NUMBER="${i#*=}"
                        shift
                        ;;
                -f=*|--file=*)
                        FILE="${i#*=}"
                        shift
                        ;;
                -h|--help)
                        echo "Usage: ./sdm -n=<number_of_iterations> -l=<link_of_directory> -f=<file_name_pattern>"
                        shift
                        exit 0
                        ;;
                --default)
                        DEFAULT=YES
                        shift
                        ;;
                *)
                        throwErr
                ;;
        esac
done

while [ "$NUMBER" != 0 ]
do
        FILENAME="${FILE//$/$NUMBER}"
        wget "${LINK}${FILENAME}"
        #  echo "wget $LINK$FILENAME"
NUMBER=$[$NUMBER-1]
done