ShellCheck: Find Bugs in Shell Scripts

In production-ready projects, every detail matters. Shell scripts are no exception.

Many engineers rely on trial and error when working with shell scripts, but there’s a more efficient approach.

Use ShellCheck, a powerful static analysis tool for bash/sh shell scripts.

It detects common issues like:

• Syntax errors

• Unused variables

• Command substitutions that might fail

Also it provides warnings and suggestions to help you identify and fix potential issues. It can also check for compatibility across different shells (e.g., bash, sh, zsh), ensuring your scripts can run on various systems without modification.

Here is the demo.

Integrate ShellCheck in CI/CD

Shellcheck can be seamlessly integrated into your infrastructure’s CI pipelines as a linter, ensuring that your shell scripts are bug-free.

If ShellCheck detects any issues or warnings within your script, it will return a non-zero exit code and cause the CI job to fail.

This will alert you to problems before they impact your workflow.

Here is an example of GitHub Actions Workflow that uses shellcheck.

name: ShellCheck

on:
  push:
    branches:
      - main
  pull_request:
    branches:
      - main

jobs:
  shellcheck:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout code
        uses: actions/checkout@v2

      - name: Install ShellCheck
        run: sudo apt-get install shellcheck

      - name: Run ShellCheck on Common
        run: shellcheck scripts/common.sh
        
      - name: Run ShellCheck on Master Scriopt
        run: shellcheck scripts/master.sh

Real-World Benefits of ShellCheck

When working on production-ready projects, reliability and maintainability are key. By integrating ShellCheck into your workflow, you can catch bugs early, improve code quality, and ensure your scripts run reliably in production.

Overall,

1. It Prevents script-related failures in production.

2. Ensures all scripts follow the same coding standards.

3. Identifies vulnerabilities, such as incorrect file permissions or unsafe use of eval.