curl
curl [-I] [-s] <address>
Risk: Safe
What it does
Asks an address for a page and prints the answer.
When to use it
To test a hatch from your laptop, with no browser.
Example
$ curl localhost:8080Ask hatch 8080 on this laptop for its page.
$ curl -I localhost:8080Only the top of the reply, with the status code.
$ curl 127.0.0.1:8080The same, using localhost's number.
Learn it in: Networking crash course · Official docs