Linux: Convert a text file with URLs to a HTML file with clickable links

We have a file called URLs.txt with URLs:

http://www.google.com
http://www.reddit.com

We want to create an HTML file with clickable URLs:

Example:

<a href="http://www.google.com">http://www.google.com</a>
<a href="http://www.reddit.com">http://www.reddit.com</a>

Use perl to make the URL's clickable:

$ perl -p -e 's/(.*)/<a href="\1" target="_blank">\1<\/a><br>/' urls.txt > urls.html

New let's complete the HTML file:

Add the HTML, head, title, and body tags:

$ sed -i '1i <!DOCTYPE html><html><head><title>Sitemap</title></head><body>' urls.html

Add the closing tags at the end of the HTML file:

$ echo "</body></html>" >> urls.html

Resulting file:

<!DOCTYPE html>
<html>
    <head>
        <title>Sitemap</title>
    </head>
    <body>
        <a href="http://www.google.com">http://www.google.com</a>
        <a href="http://www.reddit.com">http://www.reddit.com</a>
    </body>
</html>