setting up Thonny on Linux Mint 19
Properly install Python3
sudo apt-get install -y python3 python3-pip python3-setuptools
Now you should be able to install the Flash utility and Thonny into your user account
pip3 install thonny pip3 install esptool
Make your the locally installed apps are on your shell's PATH
Add this to the end of your .bashrc or,zshrc if it is not already there:
This will not take effect until next time you start a new shell or log in again, but before you do that....
USB Port Access
Likely, your user will not yet be allowed to write to the USB serial port. You can fix that by giving them membership in the dialout user group.
sudo usermod -a -G dialout $USER
This is assuming you are logged in as the user who want to run Thonny. Note that you might need to log out and back in again for this to take effect, so this would be good time to do that before you can start accessing that port.
Load MicroPython onto your ESP controller board
Download the right firmware from micropython.org, then ...
esptool.py --chip esp32 --port /dev/ttyUSB0 erase_flash esptool.py --chip esp32 --port /dev/ttyUSB0 write_flash --flash_mode dio --flash_size detect 0x1000 esp32-ppp-fix.bin
You should now be able to fire up Thonny. Selection Options -> Maintain Plugins and install esptool and thonny-esp, then restart Thonny. After you select a generic python interpreter and select the correct the USB port (it should find the correct default, assuming you have the ESP plugged in), you should see a REPL dialog in the lower half of the Thonny window.