A simple script to run ShellCheck on all shell scripts in a git repository with support for GitHub Actions annotations.

Why?

Most projects end up with at least a few shell scripts scattered around. While ShellCheck is great for checking individual files, it becomes tedious to manually track all scripts across a project, especially when they don’t have standard extensions or are located in various directories.

You could use shellcheck '**/*.sh', but this doesn’t work for scripts without extensions. Many projects resort to Makefiles or Rakefiles that manually track script paths, but this approach is error-prone and requires constant maintenance.

For GitHub Actions workflows, ShellCheck comes pre-installed and is easy to set up, but it doesn’t support GitHub Actions annotations out of the box. You’re still left with the same problem of tracking script locations.

This script solves these issues by automatically discovering all shell scripts in a git repository and running ShellCheck on them. It identifies shell scripts by using git ls-files to find *.sh, *.bash, and *.bats files, then uses git grep to find files with Bash/Sh shebangs. This catches scripts regardless of their file extension or location.

Installation

Install this extension using the GitHub CLI:

gh extension install built-fast/gh-shellcheck

Prerequisites:

Local Usage

Using this script is meant to be done without thinking. Just run gh shellcheck in a git repository.

gh shellcheck

By default, it will output the same format that ShellCheck does, with color enabled unless you ask it not to or pipe the script to something else.

If you want to see JSON, which ShellCheck supports on it’s own, you can use

gh shellcheck -f json

ShellCheck’s JSON output isn’t pretty so I piped it to jq to make it look a bit nicer.

Untracked Files

If you want to scan untracked files, you can use:

gh shellcheck --untracked

Include/Exclude Paths

You can specify which paths to include or exclude from checking:

# Check all files (default)
gh shellcheck

# Check only files in scripts/ directory
gh shellcheck -- scripts/

# Exclude files in tests/ directory
gh shellcheck -- :tests/

# Include scripts/ but exclude scripts/old/
gh shellcheck -- scripts/ :scripts/old/

# Multiple includes and excludes
gh shellcheck -- src/ bin/ :src/vendor/ :bin/legacy/

The -- separator is required when specifying paths. Paths prefixed with : are excluded, while paths without the prefix are included. If you specify include paths, only files matching those paths will be checked. Exclude paths are then applied to remove any matching files from the final set.

CI Usage

In your workflow, do something like:

jobs:
  shellcheck:
    name: Run shellcheck

    runs-on: ubuntu-latest

    permissions:
      contents: read

    steps:
      - uses: actions/checkout@v4

      - name: Run shellcheck
        env:
          GH_TOKEN: $
        run: |
          gh extension install built-fast/gh-shellcheck
          gh shellcheck

License

MIT License.

Tags: Bash, GitHub, Shellcheck