Why is wget output in stderr and not in stdout?

Question

After 30 minutes of a futile attempt to intercept the output of wget , I realized that the program writes to stderr and not to stdout . A network search and stack overflow shows that this is a well-known fact.

Any idea why this is?

Answer 1

This is well known because it is in the manual .

Messages about messages on stderr common because messages are separated from normal output on stdout . This is useful when you combine several instruments with a pipe. In this case, it would be bad when the usual output and diagnostic messages were mixed.