if STREAM.isatty():

[Hongyi Zhao]

On Sat, 31 Aug 2019 09:11:22 +1000, Cameron Simpson wrote:

>   '\r' + progress_status
> 
> which backs up to the start of the line, writes the status, and leaves
> the cursor at the end.
> 
> The latter has the advantage that any subsequent output (egthe shell
> prompt after the programmke exits) will not overwrite the status string.

Thanks a lot for your revision, it makes the status more clear on using 
this trick.