This PR was started because I noticed bugs in the docs:
- The interestingness test checked for an error, but did not redirect
stderr to stdout to include it in the pipe.
- The interestingness test pipe ended with grep, but then checked for an
exit code of 1 to mark the input as interesting. However, a pipe's
overall exit code is the exit code of the rightmost command, and grep's
exit code is zero when it detects the query string, and 1 when it does
not detect the query string. So the test was backwards.
Then I wanted to test my fixes to be sure I got it right, and I realized
that the doc has no properly runnable example. This PR adds a working
example. h/t @aidint for fixing up the input.
6a9c3b64a8