How to Schedule Local Tasks Without Cron in Python

Run periodic tasks on a loop using the schedule library to mimic cron-like behavior from within Python.

Easy Python 3.9+ Jun 28, 2026 Automation & scripting 2 views 0 copies

schedule automation cron task scheduling

Requires third-party packages — install first

pip install schedule

Python code

22 lines

Python 3.9+

import schedule
import time
from datetime import datetime

def greet():
    print(f"Hello at {datetime.now().strftime('%H:%M:%S')}")

def check_time():
    now = datetime.now()
    print(f"Current time: {now:%H:%M:%S}")

schedule.every(5).seconds.do(greet)
schedule.every(10).seconds.do(check_time)
schedule.every(1).minute.do(lambda: print("One minute has passed"))

if __name__ == "__main__":
    print("Task scheduler started (runs for 30 seconds)...")
    end_time = time.time() + 30
    while time.time() < end_time:
        schedule.run_pending()
        time.sleep(1)
    print("Scheduler stopped.")

Output

stdout

Task scheduler started (runs for 30 seconds)...
Hello at 14:23:05
Current time: 14:23:10
Hello at 14:23:10
Current time: 14:23:15
Hello at 14:23:15
One minute has passed
Hello at 14:23:20
Current time: 14:23:25
Hello at 14:23:25
Hello at 14:23:30
Current time: 14:23:30
Hello at 14:23:35
Scheduler stopped.

How it works

The schedule library provides a human-friendly syntax for defining recurring jobs without shell cron. schedule.every(5).seconds.do(greet) registers greet to run every 5 seconds. The main loop calls schedule.run_pending() to execute any jobs whose scheduled time has passed, then sleeps 1 second to avoid busy waiting. Each job runs its Python function in the same thread, so long-running tasks will block others unless you add threading.

Common mistakes

Forgetting to call `schedule.run_pending()` in the loop — jobs are defined but never executed.
Using blocking sleep inside a job and delaying the scheduler loop.
Omitting `time.sleep(1)` — without it, the loop hogs CPU by calling `run_pending` thousands of times per second.
Assuming jobs run exactly on the second — `schedule` checks the clock every iteration, so a 5-second job may drift if other jobs take time.

Variations

Use `schedule.every().day.at("10:30").do(task)` for daily one-time jobs.
Wrap the loop in a daemon thread to run scheduled jobs alongside an interactive program.

Real-world use cases

Running a periodic health check on a local database or API endpoint and logging results.
Cleaning up temporary files in a downloads folder every hour during development.
Sending a reminder notification or email at a fixed time each day from a desktop application.

How to Schedule Local Tasks Without Cron in Python

Python code

Output

How it works

Common mistakes

Variations

Real-world use cases

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Python code

Output

How it works

Common mistakes

Variations

Real-world use cases

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