4d ago

Does it make sense to use --show-error by itself in curl

I was trying to read up on it and just based off of the manual it seems not to make sense if I'm not using --silent alongside it, but I found this one article stating otherwise: https://nrogap.medium.com/show-error-response-for-curl-64666cd64330

I can't figure out if it's just AI slop or badly researched since it doesn't even show a real URL to test the commands against.

4 comments

I've had to use that flag.
--silent is useful when you don't want the progress bar or you're piping curl into something else. I like to do curl | tar -zxv to download and decompress at the same time, I've even tar -zc | curl to upload a backup taking no disk space to do so.
The problem however is it's really silent: if it fails, it exits with a non-zero code and that's it. Great when you don't want debug info to interfere, annoying when you need to debug it.
So you can opt-in to print some errors when in silent mode, but otherwise be silent.
- So in your experience it doesn't do something more if I don't provide --silent
- Sounds like tmpfs would be more reliable than streaming data directly?
  
  They're just examples of things you could pipe curl into, but no not really. If the download fails you end up with an incomplete file in your tmpfs anyway, and have to retry. Another use I have is curl | mysql to restore a database backup.
  If the server supports resuming, I guess that can be better than the pipe, but that still needs temporary disk space, and downloads rarely fail. You can't corrupt downloads over HTTPS either as the encryption layer would notice it and kill the connection, so it's safe to assume if it downloaded in full, it's correct.
  With downloads being IO bound these days, it's nice to not have to read it all back and write the extracted files to disk afterwards. Only writes the final files once.
  That's far from the weirdest thing I've done with pipes though, I've installed Windows 11 on a friend's PC across the ocean with a curl | zstd | pv | dd, and it worked. We tried like 5 different USBs and different ISOs and I gave up, I just installed it in a VM and shipped the image.