Document How the ProgressBar on Console Uses stderr #18177
Description
I feel that a note should be added to the ProgressBar documentation stating the console output will always be sent through stderr. This is a subtle nuance for anybody who treat stderr as an error, similar to how a return code > 0 would indicate a failure of a command.
Use case: I use cronic to wrap command execution for cron jobs so that any error output, or result code > 0, is treated as a failure and an email be sent notifying developers of a problem. cronic relies on the existence of either output in stderr or a non-zero result code to make this determination. Suffice it to say, I've been spinning my wheels trying to figure out why my commands are failing successfully.