01 · FoundationsLab 5 / 59
Challengelinux
Bash Automation: A Script You Can Trust — Challenge
Write a backup script that fails loudly instead of silently, and schedule it so a missed run does not go unnoticed.
- Time
- 20 min
- Level
- Beginner
- Objectives
- 4 objectives
- Cost
- Free
Where this fits in the platform
This lab adds
- A script that fails loudly instead of half-running
Which lets you
—
Before you start
You will need
- bash 4+
- systemd or cron
You do not need these already — the lab environment below provides them.
You will be able to
- Write a script that stops at the first real error
- Quote variables so a space cannot become a second argument
- Exit with codes that CI and systemd can act on
- Schedule work and detect a run that never happened
Cost — Free
— no cloud resources
The goal#
Achieve the same outcome as Bash Automation: A Script You Can Trust, from an empty starting point, without the steps.
There is a backup script on the server. It has 'run successfully' every night for eight months. The backup directory is empty.
It has been exiting 0 the whole time, because nothing in it ever checked whether anything worked.
Hands-on environment
Run this lab in a real terminal, free and in your browser. The environment is temporary and yours alone — break it as much as you like.
Start the challengeOpens in Killercoda, in a new tab — keep this page open for the steps.
This is the guided lab's environment — the same machine, with its walkthrough on the left. Work from the task above and leave those steps alone until you are done, or you are reading the answers.
Run it on your own machine
Run this lab on your own machine. One command starts the environment, with everything the lab needs already installed:
You will need:
- bash
git clone https://github.com/EgyKode/EgyKode-lab.git
cd EgyKode-lab
./egykode start
./egykode shell
ssh node1You need Docker and Git installed. Everything else runs inside the environment. The first start downloads it and takes a few minutes; later starts are seconds.
Not sure what you already have? Run: npm run doctor — it checks and changes nothing.
Anything you tick here is your own record. EgyKode cannot see inside that terminal, so the success criteria stay self-assessed even when the environment checks your work for you.
What must be true when you are done
Step 1 of 3
What must be true when you are done#
- The script exits non-zero when any step fails, proven by deliberately breaking one.
- Running it twice does not corrupt or duplicate the previous backup.
- A backup older than the retention window is removed automatically.
- A failed run is visible without anyone reading the logs.
Rules#
- Do not open the guided lab until you are finished, or until you have been stuck on the same thing for 20 minutes. Being stuck is the exercise; staying stuck is not.
- Official documentation is allowed and encouraged. In the job it is the first thing you open.
- Verify every criterion yourself with a command whose output you can read. "It looks right" is not a check.
If you get stuck#
Work in layers rather than restarting things:
- What did you expect to happen, exactly?
- What happened instead — the error text, not a paraphrase?
- Which layer is that error from?
- What is the smallest command that proves the layer below is fine?
That sequence is the skill this tier exists to build. The commands are lookup-able; the sequence is not.
You are done when
0 of 4
The concept behind it
Next up
Lab 5 of 59 on the project path