Bash script that extracts HTML title tag from files and creates a table of contents. Assumes files are named {number}.html.

generate_table_of_contents.sh

#!/bin/bash

END=$(ls -l | grep ".html" | wc -l)
START=1

for (( i=$START; i<=$END; i++ ))
do
	cat ./$i.html | grep -oE "<title>.*</title>" | sed 's/<title>/'"$i"'.html /' | sed 's/<\/title>//' | head -n 1;
done

Usage:

cd directory-with-html-files
chmod +x generate_table_of_contents.sh
./generate_table_of_contents.sh
1.html title 1
2.html title 2
3.html title 3

You might want to redirect the output to a file, for example: ./generate_table_of_contents.sh > table_of_contents.txt