shell-script-quality

Shell Script Quality

Comprehensive shell script linting and testing using ShellCheck and BATS with 2025 best practices.

When to Use

• User asks to check bash/sh scripts for errors or fix ShellCheck warnings
• Need to write shell script tests or set up CI/CD for shell scripts
• Even if they just say "fix this script" or "add tests for the shell script"

Quick Start

Copy this workflow checklist and track your progress:

Shell Script Quality Workflow:
- [ ] Step 1: Lint with ShellCheck
- [ ] Step 2: Fix reported issues
- [ ] Step 3: Write BATS tests
- [ ] Step 4: Verify tests pass
- [ ] Step 5: Integrate into CI/CD

Core Workflow

Step 1: Lint with ShellCheck

Note: When searching for patterns across scripts, use the dedicated Grep Tool (with pattern/type parameters) instead of calling grep or find directly, as per AGENTS.md.

# Lint single file
shellcheck script.sh

# Lint all scripts
find scripts -name "*.sh" -exec shellcheck {} +

# Use config file if present
shellcheck -x script.sh

Common fixes: See SHELLCHECK.md for fix patterns

Step 2: Fix Reported Issues

Apply fixes for common warnings:

• SC2086: Quote variables: "$var" not $var
• SC2155: Separate declaration and assignment
• SC2181: Check exit code directly with if ! command

For detailed fixes: See SHELLCHECK.md

Step 3: Write BATS Tests

#!/usr/bin/env bats

setup() {
    source "$BATS_TEST_DIRNAME/../scripts/example.sh"
}

@test "function succeeds with valid input" {
    run example_function "test"
    [ "$status" -eq 0 ]
    [ -n "$output" ]
}

@test "function fails with invalid input" {
    run example_function ""
    [ "$status" -ne 0 ]
    [[ "$output" =~ "ERROR" ]]
}

Test patterns: See BATS.md for comprehensive testing guide

Step 4: Run Tests

# Run all tests
bats tests/

# Run with verbose output
bats -t tests/

# Run specific file
bats tests/example.bats