I have to deal with lots of things that hide the actual URL from me. I have to grab some quarantined URL to get the real URL. All I want is the Location header:

$ 3xx http://www.some-filter-thing.com/?deadbeef
https://www.perl.com/

And, I have to do this in a variety of environments where different tools are avialable so I've done the same thing in different tools.

There's a Mojolicious program that has four paths. Three of those redirect in this chain:

* http://127.0.0.1:3000/three
* http://127.0.0.1:3000/two
* http://127.0.0.1:3000/one
* http://127.0.0.1:3000/none

Start the app:

$ perl app.pl daemon
[Tue Mar 19 21:15:09 2019] [info] Listening at "http://*:3000"
Server available at http://127.0.0.1:3000

Now try it. Each prints the redirect chain. Standard output is the URLs and anything else is on standard error.

$ python3.7 python/3xx http://127.0.0.1:3000/three
http://127.0.0.1:3000/two
http://127.0.0.1:3000/one
http://127.0.0.1:3000/none

$ ruby ruby/3xx http://127.0.0.1:3000/two
http://127.0.0.1:3000/one
http://127.0.0.1:3000/none

$ perl5.28.0 perl/3xx http://127.0.0.1:3000/one
http://127.0.0.1:3000/none

Get the last one with tail:

$ python3.7 python/3xx http://127.0.0.1:3000/three | tail -1
http://127.0.0.1:3000/none

• 0 - Found a Location header
• 1 - The request was a success, but there was no Location header
• 2 - The request was some sort of error
• 255 - There was a program error

Sure, show me how. But it's not as simple as sending a head request and grabbing the Location header. Some servers won't respond to that and I still have to strip out the header name. I end up with a pipeline in an alias.