How to Create Main Menus for CLI Scripts in Python

The aim of this page📝 is to share an approach for the simple creation of terminal menus with Python scripts, ideally utilizing a simple library function for all menus.

1. Given a list ["retry", "abort", cancel"]
2. Print the list with numbers next to the list starting from 1

-- MENU --
1. retry
2. abort
3. cancel

3. Return 1-indexed value in the list

Please select the number (e.g. 1): 2
>>> Aborting...

I am building an automation platform hosting scripts in a dedicated folder

• If curious, see the insightful treatment of Platform < The Evolution of Automation at Google < Site Reliability Engineering
• I have scripts in a folder which I execute to get the menu listing all utils with a keystroke (handled by a bash alias)
• …that is a different story altogether, let’s just look at the source code, the most important are the 4 last lines
• ……and of course, print("running => ", selected_tool) is just for demo purposes here, I'll look_up a proper utility

# __main__.py
import os
import sys
sys.path.append("./")
sys.path.append("../")
os.chdir(sys.argv[0])
try:
    from lib.python.printer import print_header
    from lib.python.make_menu import Terminal_Menu
except:
    raise
print_header("SNOWPLOW SUPPORT AUTOMATION PLATFORM", fill_char="-")
SSAP_menu = Terminal_Menu(menu_items=next(os.walk("."))[1])
SSAP_menu.print_menu()
selected_tool = SSAP_menu.select_menu_item()
print("running =>", selected_tool)

• Let’s run that

▶ python .\support_utils\
-------------- SUPPORT AUTOMATION PLATFORM -----------------
1 consul_updater
2 defaults_updater
3 example_event_sender
4 log_reducer
Select a number of an item (e.g. 1): 1
running => consul_updater

The menu is a class with members separated into a command method (print) and a query method (get)

• If curious, see Command and Query Separation — Martin Fowler or google the concept
• Let’s look into the Terminal_Menu class located in make_menu.py

""" menu_maker.py """
class Terminal_Menu:
    def __init__(self, menu_items: list):
        self.menu_items = menu_items

    def print_menu(self):
        for i, single_item in enumerate(self.menu_items, start=1):
            print(i, single_item)

    def select_menu_item(self):
        selection = int(input("Select an number of an item (e.g. 1): "))
        return self.menu_items[selection - 1]

1. the object is initialized with a random list — a source for your future menu
2. the command print_menu uses enumerate() method to create a numbered/ordered list from menu_items (for enumerate, see https://medium.com/p/616cbf2de913)
3. the query method select_menu_items() asks a user for the number and returns the 1-indexed item from a list by decrementing the client input