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pipe vs. tty: output is different: curl -v vs. curl -v | cat

From: Henrique Vicente de Oliveira Pinto <>
Date: Fri, 15 Jun 2018 11:11:48 -0300


I'm trying to understand what is happening here...

If I pipe the curl output to another process, I get a different output than
if curl prints directly on stdout.

Example / How to reproduce:

1. curl -v
2. curl -v | cat
then diff both outputs.

On the second time besides getting the multiline progress bar I get some
extra info (especially when using --verbose) -- mostly, lots of "{ [219
bytes data]" blocks.

I have tried using --trace and --trace-ascii to avoid getting such info
lines but failed to figure out how to do so.

Question: What would be the most straight-forward way for me to get exactly
the same output I get when I use curl directly?

This code seems to be the culprit, but I haven't gone deeper into the

Best regards,

Henrique Vicente

Received on 2018-06-15