$ ping google.com
Copy the IP address and paste it into a browser.
$ traceroute google.com
$ man traceroute
breakdown of a URL - scheme:[//[user:password@]host[:port]][/]path[?query][#fragment]
see link
$ curl -i http://github.com
semantic HTML <section>
, <article>
, <main>
chmod a-w my-file.txt
to remove write permissions for all user groups