doc: Add environemt variable overriding to get started
This comit adds details about the overriding of environment variables such as
ESPPORT and ESPBAUD to the get started guide.
@@ -315,6 +315,33 @@ That's all what you need to get started with ESP32!
Now you are ready to try some other :idf:`examples`, or go right to developing your own applications.
+Environment Variables
+=====================
+
+Some environment variables can be specified whilst calling ``make`` allowing users to **override arguments without needing to reconfigure them using** ``make menuconfig``.
+
++-----------------+--------------------------------------------------------------+
+| Variables | Description & Usage |
++=================+==============================================================+
+| ``ESPPORT`` | Overrides the serial port used in ``flash`` and ``monitor``. |
+| | |
+| | Examples: ``make flash ESPPORT=/dev/tty/USB0``, |
+| | ``make monitor ESPPORT=COM1`` |
++-----------------+--------------------------------------------------------------+
+| ``ESPBAUD`` | Overrides the serial baud rate when flashing the ESP32. |
+| | |
+| | Example: ``make flash ESPBAUD=9600`` |
++-----------------+--------------------------------------------------------------+
+| ``MONITORBAUD`` | Overrides the serial baud rate used when monitoring. |
+| | |
+| | Example: ``make monitor MONITORBAUD=9600`` |
++-----------------+--------------------------------------------------------------+
+
+.. note::
+ Users can export environment variables (e.g. ``export ESPPORT=/dev/tty/USB0``).
+ All subsequent calls of ``make`` within the same terminal session will use
+ the exported value given that the variable is not simultaneously overridden.
+
Updating ESP-IDF
================
