#!/bin/bash

if [ $# -ne 1 ]; then
    echo "usage: $0 format"
    echo "NB: page numbers start at 1"
    echo "NB: format should have leading 0 information"
    echo "example:"
    echo "$0 http://example.net/path/chapter/%04d.jpg"
    exit
fi

format=$1

echo "Start $format"

getpage() {
    url=$(printf $format $pagenum)
    wget $url 2> /tmp/$$.log
    if grep "404 Not Found" /tmp/$$.log; then return 1;
    elif grep "Length: unspecified [text/html]" /tmp/$$.log; then return 1;
    else return 0;
    fi
}

pagenum=1
while getpage; do
    echo "$pagenum complete."
    pagenum=$(($pagenum + 1))
done

echo "End $format"

rm -f /tmp/$$.log