Great question. Haven’t heard or thought about this one yet.
Did some testing locally via Netlify Dev (which runs the same redirect engine as Netlify Prod I believe) and did find that splats support after-the-splat path filters… which is news to me and also so cool.
Redirects aren’t quite UNIX-style directory pathing, so you don’t need the double star, but in testing this rule (in _redirects file format, not toml format):
I got the following results
/something/somewhere/foo -> 302 -> /bar
and further, the :splat directive actually does work to re-add those path values if you need to (cool!)… so with the redirect changed to:
The _redirect file must be present in the publish directory. Depending on where you put it in your Jekyll project hierarchy, there’s a good chance it’s not getting pushed over to the publish directory.
Jekyll also ignores files that start with an underscore by default.