cmd terminal

[Gribouillis]

If one wishes to display the output from the command, how can it be obtained from the Popen call and displayed in a tkinter window?

You can write

process =  subprocess.run(['command', 'arg', 'arg'], capture_output=True, encoding='utf8')
print(process.stdout)
print(process.stderr)

Then instead of printing the strings process.stdout and process.stderr, you can insert them in a Tkinter Text widget for example.