Gedit, Execute Highlighted Code

• In the gedit menu: Tools/Manage External Tools.
• On the left, add: Execute Highlighted Python Code.
• On the right, add:

#!/usr/bin/env python3
import sys
exec(sys.stdin.read())

• At the bottom,
  • Choose a shortcut key: Alt+X.
  • Input: Current selection (default to document).
  • Output: Display in bottom pane.
  • Do not change the other parameters.
• Create a python document (.py), add Python code, highlight the code, and press Alt+X: a bottom pane opens showing the results.
• The external tool is now part of gedit and ready to use.