[Wingy]

curl should probably scream when it detects piping unencrypted wan (not local ips) connections to shell, sort of like what openssh does when a host’s fingerprint changes

[mr_mitm]

How could curl detect where it's piped to?

[take-five]

Something like (in Python)

os.isatty(sys.stdout.fileno())

[Zambyte]

That doesn't say where it's piped though. It could be redirected to a file, or piped to something harmless like jq.

[timando]

Iterate through /proc/<pid>/fd and check for the pipe id in the symlink target.

[adamomada]

The shell would have to give the warning