Last Updated: 2024-12-03

Whenever printing error messages from shell scripts, make sure to redirect to STDERR, otherwise callers will not be able to react correctly.

Here is what you should do

echo "$lesson not found. Please contact customer support" >&2

Here's how it works: &2 copies the destination of file descriptor #2 (STDERR by default). The > tells echo where to send the output that is usually STDOUT (file descriptor #1). Bringing it together, this means echo's standard output gets sent to STDERR.

Resources

• https://stackoverflow.com/questions/2990414/echo-that-outputs-to-stderr