Passing serial port as ENV variable is inconsistent (IDFGH-3506)

[kzyapkov]

If one wants to specify the serial port for idf.py in environment instead of cli option, they have to set ESPPORT. However, idf_monitor.py probes ESPTOOL_PORT. None of those are in the docs or --help output so I had to dig through the code.

I think this should be added to the documentation, output of idf.py --help and made consistent accross tools.

[Alvin1Zhang]

Thanks for reporting, we will look into.

[dobairoland]

Hi @kzyapkov. Have you read this page as well? It is mentioned at several places.

But you are right that it could useful to mention this in idf.py --help as well.

[kzyapkov]

Thanks, saw the note. That's a lot of text to read for something like this though, please add a note in the -p option docstring.