Building Your First Command-Line Project

Knowing syntax and being able to build something are different skills. This lesson walks through structuring a small, complete command-line program from scratch.

Planning before coding

Before writing a line of code, write down: what does the program do, what data does it need to remember, and what are the menu options a user sees. For a simple to-do list app:

• Add a task
• View all tasks
• Mark a task as done
• Exit

Building the menu loop

def main():
    tasks = []
    while True:
        print("\n1. Add task")
        print("2. View tasks")
        print("3. Exit")
        choice = input("Choose an option: ")

        if choice == "1":
            task = input("Task description: ")
            tasks.append({"task": task, "done": False})
        elif choice == "2":
            for i, t in enumerate(tasks):
                status = "x" if t["done"] else " "
                print(f"[{status}] {i + 1}. {t['task']}")
        elif choice == "3":
            break
        else:
            print("Invalid option, try again.")

if __name__ == "__main__":
    main()

Why if __name__ == "__main__":

This guard means main() only runs when you execute this file directly - not if you later import it as a module into another file. It is a standard convention in almost every real Python script.

Extending it yourself

Once this runs, try adding: marking a task done (loop through tasks and flip "done" to True), deleting a task, or saving tasks to a file using the pattern from the File I/O lesson so they persist between runs. This kind of self-directed extension is exactly what turns a tutorial exercise into a real portfolio project.