That’s --fail-with-body, using two dashes in front of the name.

This is a brand new command line option added to curl, to appear in the 7.76.0 release. This function works like --fail but with one little addition and I’m hoping the name should imply it good enough: it also provides the response body. The --fail option has turned out to be a surprisingly popular option but users have often repeated the request to also make it possible to get the body stored. --fail makes curl stop immediately after having received the response headers – if the response code says so.

--fail-with-body will instead first save the body per normal conventions and then return an error if the HTTP response code was 400 or larger.

To be used like this:

curl --fail-with-body -o output https://example.com/404.html

If the page is missing on that HTTPS server, curl will return exit code 22 and save the error message response in the file named ‘output’.

Not complicated at all. But has been requested many times!

This is curl’s 238th command line option.