Bash script for downloading all content of learnyousomeerlang.com and creating a single html

download_learnyousomeerlang.sh

#!/bin/bash
FIRST_URL="http://learnyousomeerlang.com/introduction"
FOLDER="html"
OUTPUT_FILENAME="learnyousomeerlang.html"

mkdir $FOLDER
url=$FIRST_URL
i=1

while true; do
	echo "Downloading $url"
	base="$(basename $url)"

	if [ "$i" -lt 10 ]; then
		filename="$FOLDER/0$i-$base"
	else
		filename="$FOLDER/$i-$base"
	fi

	wget -q -O "$filename" "$url"

	url=`grep -o '.*<a href="[^"]*" title="Next chapter">' "$filename" | sed -nr 's/.*href="([^"]*)" title.*/\1/p'`

	if [ -z "$url" ] || [ "$url" = "http://learnyousomeerlang.com/content" ]; then
		break
	fi
	i=$((i+1))
done

#create one html
for f in $FOLDER/*; do
	xmllint --html --xpath "//div[@id='content']" $f >> $OUTPUT_FILENAME
done