⚠️ It Works in Terminal... But Cron Fails Quietly

A real Linux failure you can reproduce — and the 3-line fix that makes Cron jobs reliable.

Author

Arbaz M
August 19, 2025

When Your Cron Job Runs… But Does Nothing

Alright, tell me if this has ever happened to you. You set up a cron job, it looks perfect, you wait a minute… nothing. No output, no logs, no errors. Just silence.

That’s exactly the failure we recreated in my latest Linux simulation.

What Happened

I built a small backup script. When I ran it manually, everything worked fine — data archived, backups created.

But when cron ran the same script? It failed silently.

The Debugging

Here’s the catch: cron is not your shell.

  • It doesn’t load .bashrc or .zshrc

  • It runs with a minimal PATH

  • And it executes from a different working directory

So relative paths like ./app/do_backup.sh broke instantly.

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📂 Takeaway Code Snippet

❌ Failing entry

* * * * * bash ./app/do_backup.sh >> logs/cron.log 2>&1

✅ Fixed entry

SHELL=/bin/bash
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
* * * * * cd /absolute/path/to/project && /usr/bin/env bash app/do_backup.sh >> logs/cron.log 2>&1

Just three small guardrails — SHELL, PATH, and cd — make cron behave like your terminal.

▶️ Full Walkthrough

👉 I recorded the entire failure + fix step by step. Watch it here: https://youtu.be/gNs-1WjlImU

Why It Matters

Cron powers critical jobs — backups, cleanups, reports.
One wrong path, and you might be missing backups for weeks without realizing it.

This demo shows you exactly how to avoid that trap.

👋 Final Note

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