feat: add shell-scripting plugin with bash-pro, posix-shell-pro, and 3 skills

Fantastic work, Ryan! You delivered an exceptional shell-scripting plugin with comprehensive coverage of defensive programming, static analysis, and testing patterns. Your responsiveness to feedback and commitment to quality are exactly what we value in this project. Thanks for the great contribution! 🎉
2026-03-18 17:47:16 +00:00 · 2025-10-18 17:36:56 -07:00
parent b8f35d943d
commit f6a06c793a
6 changed files with 2221 additions and 1 deletions
--- a/plugins/shell-scripting/skills/bash-defensive-patterns/SKILL.md
+++ b/plugins/shell-scripting/skills/bash-defensive-patterns/SKILL.md
@@ -0,0 +1,533 @@
+---
+name: bash-defensive-patterns
+description: Master defensive Bash programming techniques for production-grade scripts. Use when writing robust shell scripts, CI/CD pipelines, or system utilities requiring fault tolerance and safety.
+---
+
+# Bash Defensive Patterns
+
+Comprehensive guidance for writing production-ready Bash scripts using defensive programming techniques, error handling, and safety best practices to prevent common pitfalls and ensure reliability.
+
+## When to Use This Skill
+
+- Writing production automation scripts
+- Building CI/CD pipeline scripts
+- Creating system administration utilities
+- Developing error-resilient deployment automation
+- Writing scripts that must handle edge cases safely
+- Building maintainable shell script libraries
+- Implementing comprehensive logging and monitoring
+- Creating scripts that must work across different platforms
+
+## Core Defensive Principles
+
+### 1. Strict Mode
+Enable bash strict mode at the start of every script to catch errors early.
+
+```bash
+#!/bin/bash
+set -Eeuo pipefail  # Exit on error, unset variables, pipe failures
+```
+
+**Key flags:**
+- `set -E`: Inherit ERR trap in functions
+- `set -e`: Exit on any error (command returns non-zero)
+- `set -u`: Exit on undefined variable reference
+- `set -o pipefail`: Pipe fails if any command fails (not just last)
+
+### 2. Error Trapping and Cleanup
+Implement proper cleanup on script exit or error.
+
+```bash
+#!/bin/bash
+set -Eeuo pipefail
+
+trap 'echo "Error on line $LINENO"' ERR
+trap 'echo "Cleaning up..."; rm -rf "$TMPDIR"' EXIT
+
+TMPDIR=$(mktemp -d)
+# Script code here
+```
+
+### 3. Variable Safety
+Always quote variables to prevent word splitting and globbing issues.
+
+```bash
+# Wrong - unsafe
+cp $source $dest
+
+# Correct - safe
+cp "$source" "$dest"
+
+# Required variables - fail with message if unset
+: "${REQUIRED_VAR:?REQUIRED_VAR is not set}"
+```
+
+### 4. Array Handling
+Use arrays safely for complex data handling.
+
+```bash
+# Safe array iteration
+declare -a items=("item 1" "item 2" "item 3")
+
+for item in "${items[@]}"; do
+    echo "Processing: $item"
+done
+
+# Reading output into array safely
+mapfile -t lines < <(some_command)
+readarray -t numbers < <(seq 1 10)
+```
+
+### 5. Conditional Safety
+Use `[[ ]]` for Bash-specific features, `[ ]` for POSIX.
+
+```bash
+# Bash - safer
+if [[ -f "$file" && -r "$file" ]]; then
+    content=$(<"$file")
+fi
+
+# POSIX - portable
+if [ -f "$file" ] && [ -r "$file" ]; then
+    content=$(cat "$file")
+fi
+
+# Test for existence before operations
+if [[ -z "${VAR:-}" ]]; then
+    echo "VAR is not set or is empty"
+fi
+```
+
+## Fundamental Patterns
+
+### Pattern 1: Safe Script Directory Detection
+
+```bash
+#!/bin/bash
+set -Eeuo pipefail
+
+# Correctly determine script directory
+SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd -P)"
+SCRIPT_NAME="$(basename -- "${BASH_SOURCE[0]}")"
+
+echo "Script location: $SCRIPT_DIR/$SCRIPT_NAME"
+```
+
+### Pattern 2: Comprehensive Function Templat
+
+```bash
+#!/bin/bash
+set -Eeuo pipefail
+
+# Prefix for functions: handle_*, process_*, check_*, validate_*
+# Include documentation and error handling
+
+validate_file() {
+    local -r file="$1"
+    local -r message="${2:-File not found: $file}"
+
+    if [[ ! -f "$file" ]]; then
+        echo "ERROR: $message" >&2
+        return 1
+    fi
+    return 0
+}
+
+process_files() {
+    local -r input_dir="$1"
+    local -r output_dir="$2"
+
+    # Validate inputs
+    [[ -d "$input_dir" ]] || { echo "ERROR: input_dir not a directory" >&2; return 1; }
+
+    # Create output directory if needed
+    mkdir -p "$output_dir" || { echo "ERROR: Cannot create output_dir" >&2; return 1; }
+
+    # Process files safely
+    while IFS= read -r -d '' file; do
+        echo "Processing: $file"
+        # Do work
+    done < <(find "$input_dir" -maxdepth 1 -type f -print0)
+
+    return 0
+}
+```
+
+### Pattern 3: Safe Temporary File Handling
+
+```bash
+#!/bin/bash
+set -Eeuo pipefail
+
+trap 'rm -rf -- "$TMPDIR"' EXIT
+
+# Create temporary directory
+TMPDIR=$(mktemp -d) || { echo "ERROR: Failed to create temp directory" >&2; exit 1; }
+
+# Create temporary files in directory
+TMPFILE1="$TMPDIR/temp1.txt"
+TMPFILE2="$TMPDIR/temp2.txt"
+
+# Use temporary files
+touch "$TMPFILE1" "$TMPFILE2"
+
+echo "Temp files created in: $TMPDIR"
+```
+
+### Pattern 4: Robust Argument Parsing
+
+```bash
+#!/bin/bash
+set -Eeuo pipefail
+
+# Default values
+VERBOSE=false
+DRY_RUN=false
+OUTPUT_FILE=""
+THREADS=4
+
+usage() {
+    cat <<EOF
+Usage: $0 [OPTIONS]
+
+Options:
+    -v, --verbose       Enable verbose output
+    -d, --dry-run       Run without making changes
+    -o, --output FILE   Output file path
+    -j, --jobs NUM      Number of parallel jobs
+    -h, --help          Show this help message
+EOF
+    exit "${1:-0}"
+}
+
+# Parse arguments
+while [[ $# -gt 0 ]]; do
+    case "$1" in
+        -v|--verbose)
+            VERBOSE=true
+            shift
+            ;;
+        -d|--dry-run)
+            DRY_RUN=true
+            shift
+            ;;
+        -o|--output)
+            OUTPUT_FILE="$2"
+            shift 2
+            ;;
+        -j|--jobs)
+            THREADS="$2"
+            shift 2
+            ;;
+        -h|--help)
+            usage 0
+            ;;
+        --)
+            shift
+            break
+            ;;
+        *)
+            echo "ERROR: Unknown option: $1" >&2
+            usage 1
+            ;;
+    esac
+done
+
+# Validate required arguments
+[[ -n "$OUTPUT_FILE" ]] || { echo "ERROR: -o/--output is required" >&2; usage 1; }
+```
+
+### Pattern 5: Structured Logging
+
+```bash
+#!/bin/bash
+set -Eeuo pipefail
+
+# Logging functions
+log_info() {
+    echo "[$(date +'%Y-%m-%d %H:%M:%S')] INFO: $*" >&2
+}
+
+log_warn() {
+    echo "[$(date +'%Y-%m-%d %H:%M:%S')] WARN: $*" >&2
+}
+
+log_error() {
+    echo "[$(date +'%Y-%m-%d %H:%M:%S')] ERROR: $*" >&2
+}
+
+log_debug() {
+    if [[ "${DEBUG:-0}" == "1" ]]; then
+        echo "[$(date +'%Y-%m-%d %H:%M:%S')] DEBUG: $*" >&2
+    fi
+}
+
+# Usage
+log_info "Starting script"
+log_debug "Debug information"
+log_warn "Warning message"
+log_error "Error occurred"
+```
+
+### Pattern 6: Process Orchestration with Signals
+
+```bash
+#!/bin/bash
+set -Eeuo pipefail
+
+# Track background processes
+PIDS=()
+
+cleanup() {
+    log_info "Shutting down..."
+
+    # Terminate all background processes
+    for pid in "${PIDS[@]}"; do
+        if kill -0 "$pid" 2>/dev/null; then
+            kill -TERM "$pid" 2>/dev/null || true
+        fi
+    done
+
+    # Wait for graceful shutdown
+    for pid in "${PIDS[@]}"; do
+        wait "$pid" 2>/dev/null || true
+    done
+}
+
+trap cleanup SIGTERM SIGINT
+
+# Start background tasks
+background_task &
+PIDS+=($!)
+
+another_task &
+PIDS+=($!)
+
+# Wait for all background processes
+wait
+```
+
+### Pattern 7: Safe File Operations
+
+```bash
+#!/bin/bash
+set -Eeuo pipefail
+
+# Use -i flag to move safely without overwriting
+safe_move() {
+    local -r source="$1"
+    local -r dest="$2"
+
+    if [[ ! -e "$source" ]]; then
+        echo "ERROR: Source does not exist: $source" >&2
+        return 1
+    fi
+
+    if [[ -e "$dest" ]]; then
+        echo "ERROR: Destination already exists: $dest" >&2
+        return 1
+    fi
+
+    mv "$source" "$dest"
+}
+
+# Safe directory cleanup
+safe_rmdir() {
+    local -r dir="$1"
+
+    if [[ ! -d "$dir" ]]; then
+        echo "ERROR: Not a directory: $dir" >&2
+        return 1
+    fi
+
+    # Use -I flag to prompt before rm (BSD/GNU compatible)
+    rm -rI -- "$dir"
+}
+
+# Atomic file writes
+atomic_write() {
+    local -r target="$1"
+    local -r tmpfile
+    tmpfile=$(mktemp) || return 1
+
+    # Write to temp file first
+    cat > "$tmpfile"
+
+    # Atomic rename
+    mv "$tmpfile" "$target"
+}
+```
+
+### Pattern 8: Idempotent Script Design
+
+```bash
+#!/bin/bash
+set -Eeuo pipefail
+
+# Check if resource already exists
+ensure_directory() {
+    local -r dir="$1"
+
+    if [[ -d "$dir" ]]; then
+        log_info "Directory already exists: $dir"
+        return 0
+    fi
+
+    mkdir -p "$dir" || {
+        log_error "Failed to create directory: $dir"
+        return 1
+    }
+
+    log_info "Created directory: $dir"
+}
+
+# Ensure configuration state
+ensure_config() {
+    local -r config_file="$1"
+    local -r default_value="$2"
+
+    if [[ ! -f "$config_file" ]]; then
+        echo "$default_value" > "$config_file"
+        log_info "Created config: $config_file"
+    fi
+}
+
+# Rerunning script multiple times should be safe
+ensure_directory "/var/cache/myapp"
+ensure_config "/etc/myapp/config" "DEBUG=false"
+```
+
+### Pattern 9: Safe Command Substitution
+
+```bash
+#!/bin/bash
+set -Eeuo pipefail
+
+# Use $() instead of backticks
+name=$(<"$file")  # Modern, safe variable assignment from file
+output=$(command -v python3)  # Get command location safely
+
+# Handle command substitution with error checking
+result=$(command -v node) || {
+    log_error "node command not found"
+    return 1
+}
+
+# For multiple lines
+mapfile -t lines < <(grep "pattern" "$file")
+
+# NUL-safe iteration
+while IFS= read -r -d '' file; do
+    echo "Processing: $file"
+done < <(find /path -type f -print0)
+```
+
+### Pattern 10: Dry-Run Support
+
+```bash
+#!/bin/bash
+set -Eeuo pipefail
+
+DRY_RUN="${DRY_RUN:-false}"
+
+run_cmd() {
+    if [[ "$DRY_RUN" == "true" ]]; then
+        echo "[DRY RUN] Would execute: $*"
+        return 0
+    fi
+
+    "$@"
+}
+
+# Usage
+run_cmd cp "$source" "$dest"
+run_cmd rm "$file"
+run_cmd chown "$owner" "$target"
+```
+
+## Advanced Defensive Techniques
+
+### Named Parameters Pattern
+
+```bash
+#!/bin/bash
+set -Eeuo pipefail
+
+process_data() {
+    local input_file=""
+    local output_dir=""
+    local format="json"
+
+    # Parse named parameters
+    while [[ $# -gt 0 ]]; do
+        case "$1" in
+            --input=*)
+                input_file="${1#*=}"
+                ;;
+            --output=*)
+                output_dir="${1#*=}"
+                ;;
+            --format=*)
+                format="${1#*=}"
+                ;;
+            *)
+                echo "ERROR: Unknown parameter: $1" >&2
+                return 1
+                ;;
+        esac
+        shift
+    done
+
+    # Validate required parameters
+    [[ -n "$input_file" ]] || { echo "ERROR: --input is required" >&2; return 1; }
+    [[ -n "$output_dir" ]] || { echo "ERROR: --output is required" >&2; return 1; }
+}
+```
+
+### Dependency Checking
+
+```bash
+#!/bin/bash
+set -Eeuo pipefail
+
+check_dependencies() {
+    local -a missing_deps=()
+    local -a required=("jq" "curl" "git")
+
+    for cmd in "${required[@]}"; do
+        if ! command -v "$cmd" &>/dev/null; then
+            missing_deps+=("$cmd")
+        fi
+    done
+
+    if [[ ${#missing_deps[@]} -gt 0 ]]; then
+        echo "ERROR: Missing required commands: ${missing_deps[*]}" >&2
+        return 1
+    fi
+}
+
+check_dependencies
+```
+
+## Best Practices Summary
+
+1. **Always use strict mode** - `set -Eeuo pipefail`
+2. **Quote all variables** - `"$variable"` prevents word splitting
+3. **Use [[ ]] conditionals** - More robust than [ ]
+4. **Implement error trapping** - Catch and handle errors gracefully
+5. **Validate all inputs** - Check file existence, permissions, formats
+6. **Use functions for reusability** - Prefix with meaningful names
+7. **Implement structured logging** - Include timestamps and levels
+8. **Support dry-run mode** - Allow users to preview changes
+9. **Handle temporary files safely** - Use mktemp, cleanup with trap
+10. **Design for idempotency** - Scripts should be safe to rerun
+11. **Document requirements** - List dependencies and minimum versions
+12. **Test error paths** - Ensure error handling works correctly
+13. **Use `command -v`** - Safer than `which` for checking executables
+14. **Prefer printf over echo** - More predictable across systems
+
+## Resources
+
+- **Bash Strict Mode**: http://redsymbol.net/articles/unofficial-bash-strict-mode/
+- **Google Shell Style Guide**: https://google.github.io/styleguide/shellguide.html
+- **Defensive BASH Programming**: https://www.lifepipe.net/
--- a/plugins/shell-scripting/skills/bats-testing-patterns/SKILL.md
+++ b/plugins/shell-scripting/skills/bats-testing-patterns/SKILL.md
@@ -0,0 +1,630 @@
+---
+name: bats-testing-patterns
+description: Master Bash Automated Testing System (Bats) for comprehensive shell script testing. Use when writing tests for shell scripts, CI/CD pipelines, or requiring test-driven development of shell utilities.
+---
+
+# Bats Testing Patterns
+
+Comprehensive guidance for writing comprehensive unit tests for shell scripts using Bats (Bash Automated Testing System), including test patterns, fixtures, and best practices for production-grade shell testing.
+
+## When to Use This Skill
+
+- Writing unit tests for shell scripts
+- Implementing test-driven development (TDD) for scripts
+- Setting up automated testing in CI/CD pipelines
+- Testing edge cases and error conditions
+- Validating behavior across different shell environments
+- Building maintainable test suites for scripts
+- Creating fixtures for complex test scenarios
+- Testing multiple shell dialects (bash, sh, dash)
+
+## Bats Fundamentals
+
+### What is Bats?
+
+Bats (Bash Automated Testing System) is a TAP (Test Anything Protocol) compliant testing framework for shell scripts that provides:
+- Simple, natural test syntax
+- TAP output format compatible with CI systems
+- Fixtures and setup/teardown support
+- Assertion helpers
+- Parallel test execution
+
+### Installation
+
+```bash
+# macOS with Homebrew
+brew install bats-core
+
+# Ubuntu/Debian
+git clone https://github.com/bats-core/bats-core.git
+cd bats-core
+./install.sh /usr/local
+
+# From npm (Node.js)
+npm install --global bats
+
+# Verify installation
+bats --version
+```
+
+### File Structure
+
+```
+project/
+├── bin/
+│   ├── script.sh
+│   └── helper.sh
+├── tests/
+│   ├── test_script.bats
+│   ├── test_helper.sh
+│   ├── fixtures/
+│   │   ├── input.txt
+│   │   └── expected_output.txt
+│   └── helpers/
+│       └── mocks.bash
+└── README.md
+```
+
+## Basic Test Structure
+
+### Simple Test File
+
+```bash
+#!/usr/bin/env bats
+
+# Load test helper if present
+load test_helper
+
+# Setup runs before each test
+setup() {
+    export TMPDIR=$(mktemp -d)
+}
+
+# Teardown runs after each test
+teardown() {
+    rm -rf "$TMPDIR"
+}
+
+# Test: simple assertion
+@test "Function returns 0 on success" {
+    run my_function "input"
+    [ "$status" -eq 0 ]
+}
+
+# Test: output verification
+@test "Function outputs correct result" {
+    run my_function "test"
+    [ "$output" = "expected output" ]
+}
+
+# Test: error handling
+@test "Function returns 1 on missing argument" {
+    run my_function
+    [ "$status" -eq 1 ]
+}
+```
+
+## Assertion Patterns
+
+### Exit Code Assertions
+
+```bash
+#!/usr/bin/env bats
+
+@test "Command succeeds" {
+    run true
+    [ "$status" -eq 0 ]
+}
+
+@test "Command fails as expected" {
+    run false
+    [ "$status" -ne 0 ]
+}
+
+@test "Command returns specific exit code" {
+    run my_function --invalid
+    [ "$status" -eq 127 ]
+}
+
+@test "Can capture command result" {
+    run echo "hello"
+    [ $status -eq 0 ]
+    [ "$output" = "hello" ]
+}
+```
+
+### Output Assertions
+
+```bash
+#!/usr/bin/env bats
+
+@test "Output matches string" {
+    result=$(echo "hello world")
+    [ "$result" = "hello world" ]
+}
+
+@test "Output contains substring" {
+    result=$(echo "hello world")
+    [[ "$result" == *"world"* ]]
+}
+
+@test "Output matches pattern" {
+    result=$(date +%Y)
+    [[ "$result" =~ ^[0-9]{4}$ ]]
+}
+
+@test "Multi-line output" {
+    run printf "line1\nline2\nline3"
+    [ "$output" = "line1
+line2
+line3" ]
+}
+
+@test "Lines variable contains output" {
+    run printf "line1\nline2\nline3"
+    [ "${lines[0]}" = "line1" ]
+    [ "${lines[1]}" = "line2" ]
+    [ "${lines[2]}" = "line3" ]
+}
+```
+
+### File Assertions
+
+```bash
+#!/usr/bin/env bats
+
+@test "File is created" {
+    [ ! -f "$TMPDIR/output.txt" ]
+    my_function > "$TMPDIR/output.txt"
+    [ -f "$TMPDIR/output.txt" ]
+}
+
+@test "File contents match expected" {
+    my_function > "$TMPDIR/output.txt"
+    [ "$(cat "$TMPDIR/output.txt")" = "expected content" ]
+}
+
+@test "File is readable" {
+    touch "$TMPDIR/test.txt"
+    [ -r "$TMPDIR/test.txt" ]
+}
+
+@test "File has correct permissions" {
+    touch "$TMPDIR/test.txt"
+    chmod 644 "$TMPDIR/test.txt"
+    [ "$(stat -f %OLp "$TMPDIR/test.txt")" = "644" ]
+}
+
+@test "File size is correct" {
+    echo -n "12345" > "$TMPDIR/test.txt"
+    [ "$(wc -c < "$TMPDIR/test.txt")" -eq 5 ]
+}
+```
+
+## Setup and Teardown Patterns
+
+### Basic Setup and Teardown
+
+```bash
+#!/usr/bin/env bats
+
+setup() {
+    # Create test directory
+    TEST_DIR=$(mktemp -d)
+    export TEST_DIR
+
+    # Source script under test
+    source "${BATS_TEST_DIRNAME}/../bin/script.sh"
+}
+
+teardown() {
+    # Clean up temporary directory
+    rm -rf "$TEST_DIR"
+}
+
+@test "Test using TEST_DIR" {
+    touch "$TEST_DIR/file.txt"
+    [ -f "$TEST_DIR/file.txt" ]
+}
+```
+
+### Setup with Resources
+
+```bash
+#!/usr/bin/env bats
+
+setup() {
+    # Create directory structure
+    mkdir -p "$TMPDIR/data/input"
+    mkdir -p "$TMPDIR/data/output"
+
+    # Create test fixtures
+    echo "line1" > "$TMPDIR/data/input/file1.txt"
+    echo "line2" > "$TMPDIR/data/input/file2.txt"
+
+    # Initialize environment
+    export DATA_DIR="$TMPDIR/data"
+    export INPUT_DIR="$DATA_DIR/input"
+    export OUTPUT_DIR="$DATA_DIR/output"
+}
+
+teardown() {
+    rm -rf "$TMPDIR/data"
+}
+
+@test "Processes input files" {
+    run my_process_script "$INPUT_DIR" "$OUTPUT_DIR"
+    [ "$status" -eq 0 ]
+    [ -f "$OUTPUT_DIR/file1.txt" ]
+}
+```
+
+### Global Setup/Teardown
+
+```bash
+#!/usr/bin/env bats
+
+# Load shared setup from test_helper.sh
+load test_helper
+
+# setup_file runs once before all tests
+setup_file() {
+    export SHARED_RESOURCE=$(mktemp -d)
+    echo "Expensive setup" > "$SHARED_RESOURCE/data.txt"
+}
+
+# teardown_file runs once after all tests
+teardown_file() {
+    rm -rf "$SHARED_RESOURCE"
+}
+
+@test "First test uses shared resource" {
+    [ -f "$SHARED_RESOURCE/data.txt" ]
+}
+
+@test "Second test uses shared resource" {
+    [ -d "$SHARED_RESOURCE" ]
+}
+```
+
+## Mocking and Stubbing Patterns
+
+### Function Mocking
+
+```bash
+#!/usr/bin/env bats
+
+# Mock external command
+my_external_tool() {
+    echo "mocked output"
+    return 0
+}
+
+@test "Function uses mocked tool" {
+    export -f my_external_tool
+    run my_function
+    [[ "$output" == *"mocked output"* ]]
+}
+```
+
+### Command Stubbing
+
+```bash
+#!/usr/bin/env bats
+
+setup() {
+    # Create stub directory
+    STUBS_DIR="$TMPDIR/stubs"
+    mkdir -p "$STUBS_DIR"
+
+    # Add to PATH
+    export PATH="$STUBS_DIR:$PATH"
+}
+
+create_stub() {
+    local cmd="$1"
+    local output="$2"
+    local code="${3:-0}"
+
+    cat > "$STUBS_DIR/$cmd" <<EOF
+#!/bin/bash
+echo "$output"
+exit $code
+EOF
+    chmod +x "$STUBS_DIR/$cmd"
+}
+
+@test "Function works with stubbed curl" {
+    create_stub curl "{ \"status\": \"ok\" }" 0
+    run my_api_function
+    [ "$status" -eq 0 ]
+}
+```
+
+### Variable Stubbing
+
+```bash
+#!/usr/bin/env bats
+
+@test "Function handles environment override" {
+    export MY_SETTING="override_value"
+    run my_function
+    [ "$status" -eq 0 ]
+    [[ "$output" == *"override_value"* ]]
+}
+
+@test "Function uses default when var unset" {
+    unset MY_SETTING
+    run my_function
+    [ "$status" -eq 0 ]
+    [[ "$output" == *"default"* ]]
+}
+```
+
+## Fixture Management
+
+### Using Fixture Files
+
+```bash
+#!/usr/bin/env bats
+
+# Fixture directory: tests/fixtures/
+
+setup() {
+    FIXTURES_DIR="${BATS_TEST_DIRNAME}/fixtures"
+    WORK_DIR=$(mktemp -d)
+    export WORK_DIR
+}
+
+teardown() {
+    rm -rf "$WORK_DIR"
+}
+
+@test "Process fixture file" {
+    # Copy fixture to work directory
+    cp "$FIXTURES_DIR/input.txt" "$WORK_DIR/input.txt"
+
+    # Run function
+    run my_process_function "$WORK_DIR/input.txt"
+
+    # Compare output
+    diff "$WORK_DIR/output.txt" "$FIXTURES_DIR/expected_output.txt"
+}
+```
+
+### Dynamic Fixture Generation
+
+```bash
+#!/usr/bin/env bats
+
+generate_fixture() {
+    local lines="$1"
+    local file="$2"
+
+    for i in $(seq 1 "$lines"); do
+        echo "Line $i content" >> "$file"
+    done
+}
+
+@test "Handle large input file" {
+    generate_fixture 1000 "$TMPDIR/large.txt"
+    run my_function "$TMPDIR/large.txt"
+    [ "$status" -eq 0 ]
+    [ "$(wc -l < "$TMPDIR/large.txt")" -eq 1000 ]
+}
+```
+
+## Advanced Patterns
+
+### Testing Error Conditions
+
+```bash
+#!/usr/bin/env bats
+
+@test "Function fails with missing file" {
+    run my_function "/nonexistent/file.txt"
+    [ "$status" -ne 0 ]
+    [[ "$output" == *"not found"* ]]
+}
+
+@test "Function fails with invalid input" {
+    run my_function ""
+    [ "$status" -ne 0 ]
+}
+
+@test "Function fails with permission denied" {
+    touch "$TMPDIR/readonly.txt"
+    chmod 000 "$TMPDIR/readonly.txt"
+    run my_function "$TMPDIR/readonly.txt"
+    [ "$status" -ne 0 ]
+    chmod 644 "$TMPDIR/readonly.txt"  # Cleanup
+}
+
+@test "Function provides helpful error message" {
+    run my_function --invalid-option
+    [ "$status" -ne 0 ]
+    [[ "$output" == *"Usage:"* ]]
+}
+```
+
+### Testing with Dependencies
+
+```bash
+#!/usr/bin/env bats
+
+setup() {
+    # Check for required tools
+    if ! command -v jq &>/dev/null; then
+        skip "jq is not installed"
+    fi
+
+    export SCRIPT="${BATS_TEST_DIRNAME}/../bin/script.sh"
+}
+
+@test "JSON parsing works" {
+    skip_if ! command -v jq &>/dev/null
+    run my_json_parser '{"key": "value"}'
+    [ "$status" -eq 0 ]
+}
+```
+
+### Testing Shell Compatibility
+
+```bash
+#!/usr/bin/env bats
+
+@test "Script works in bash" {
+    bash "${BATS_TEST_DIRNAME}/../bin/script.sh" arg1
+}
+
+@test "Script works in sh (POSIX)" {
+    sh "${BATS_TEST_DIRNAME}/../bin/script.sh" arg1
+}
+
+@test "Script works in dash" {
+    if command -v dash &>/dev/null; then
+        dash "${BATS_TEST_DIRNAME}/../bin/script.sh" arg1
+    else
+        skip "dash not installed"
+    fi
+}
+```
+
+### Parallel Execution
+
+```bash
+#!/usr/bin/env bats
+
+@test "Multiple independent operations" {
+    run bash -c 'for i in {1..10}; do
+        my_operation "$i" &
+    done
+    wait'
+    [ "$status" -eq 0 ]
+}
+
+@test "Concurrent file operations" {
+    for i in {1..5}; do
+        my_function "$TMPDIR/file$i" &
+    done
+    wait
+    [ -f "$TMPDIR/file1" ]
+    [ -f "$TMPDIR/file5" ]
+}
+```
+
+## Test Helper Pattern
+
+### test_helper.sh
+
+```bash
+#!/usr/bin/env bash
+
+# Source script under test
+export SCRIPT_DIR="${BATS_TEST_DIRNAME%/*}/bin"
+
+# Common test utilities
+assert_file_exists() {
+    if [ ! -f "$1" ]; then
+        echo "Expected file to exist: $1"
+        return 1
+    fi
+}
+
+assert_file_equals() {
+    local file="$1"
+    local expected="$2"
+
+    if [ ! -f "$file" ]; then
+        echo "File does not exist: $file"
+        return 1
+    fi
+
+    local actual=$(cat "$file")
+    if [ "$actual" != "$expected" ]; then
+        echo "File contents do not match"
+        echo "Expected: $expected"
+        echo "Actual: $actual"
+        return 1
+    fi
+}
+
+# Create temporary test directory
+setup_test_dir() {
+    export TEST_DIR=$(mktemp -d)
+}
+
+cleanup_test_dir() {
+    rm -rf "$TEST_DIR"
+}
+```
+
+## Integration with CI/CD
+
+### GitHub Actions Workflow
+
+```yaml
+name: Tests
+
+on: [push, pull_request]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Install Bats
+        run: |
+          npm install --global bats
+
+      - name: Run Tests
+        run: |
+          bats tests/*.bats
+
+      - name: Run Tests with Tap Reporter
+        run: |
+          bats tests/*.bats --tap | tee test_output.tap
+```
+
+### Makefile Integration
+
+```makefile
+.PHONY: test test-verbose test-tap
+
+test:
+	bats tests/*.bats
+
+test-verbose:
+	bats tests/*.bats --verbose
+
+test-tap:
+	bats tests/*.bats --tap
+
+test-parallel:
+	bats tests/*.bats --parallel 4
+
+coverage: test
+	# Optional: Generate coverage reports
+```
+
+## Best Practices
+
+1. **Test one thing per test** - Single responsibility principle
+2. **Use descriptive test names** - Clearly states what is being tested
+3. **Clean up after tests** - Always remove temporary files in teardown
+4. **Test both success and failure paths** - Don't just test happy path
+5. **Mock external dependencies** - Isolate unit under test
+6. **Use fixtures for complex data** - Makes tests more readable
+7. **Run tests in CI/CD** - Catch regressions early
+8. **Test across shell dialects** - Ensure portability
+9. **Keep tests fast** - Run in parallel when possible
+10. **Document complex test setup** - Explain unusual patterns
+
+## Resources
+
+- **Bats GitHub**: https://github.com/bats-core/bats-core
+- **Bats Documentation**: https://bats-core.readthedocs.io/
+- **TAP Protocol**: https://testanything.org/
+- **Test-Driven Development**: https://en.wikipedia.org/wiki/Test-driven_development
--- a/plugins/shell-scripting/skills/shellcheck-configuration/SKILL.md
+++ b/plugins/shell-scripting/skills/shellcheck-configuration/SKILL.md
@@ -0,0 +1,454 @@
+---
+name: shellcheck-configuration
+description: Master ShellCheck static analysis configuration and usage for shell script quality. Use when setting up linting infrastructure, fixing code issues, or ensuring script portability.
+---
+
+# ShellCheck Configuration and Static Analysis
+
+Comprehensive guidance for configuring and using ShellCheck to improve shell script quality, catch common pitfalls, and enforce best practices through static code analysis.
+
+## When to Use This Skill
+
+- Setting up linting for shell scripts in CI/CD pipelines
+- Analyzing existing shell scripts for issues
+- Understanding ShellCheck error codes and warnings
+- Configuring ShellCheck for specific project requirements
+- Integrating ShellCheck into development workflows
+- Suppressing false positives and configuring rule sets
+- Enforcing consistent code quality standards
+- Migrating scripts to meet quality gates
+
+## ShellCheck Fundamentals
+
+### What is ShellCheck?
+
+ShellCheck is a static analysis tool that analyzes shell scripts and detects problematic patterns. It supports:
+- Bash, sh, dash, ksh, and other POSIX shells
+- Over 100 different warnings and errors
+- Configuration for target shell and flags
+- Integration with editors and CI/CD systems
+
+### Installation
+
+```bash
+# macOS with Homebrew
+brew install shellcheck
+
+# Ubuntu/Debian
+apt-get install shellcheck
+
+# From source
+git clone https://github.com/koalaman/shellcheck.git
+cd shellcheck
+make build
+make install
+
+# Verify installation
+shellcheck --version
+```
+
+## Configuration Files
+
+### .shellcheckrc (Project Level)
+
+Create `.shellcheckrc` in your project root:
+
+```
+# Specify target shell
+shell=bash
+
+# Enable optional checks
+enable=avoid-nullary-conditions
+enable=require-variable-braces
+
+# Disable specific warnings
+disable=SC1091
+disable=SC2086
+```
+
+### Environment Variables
+
+```bash
+# Set default shell target
+export SHELLCHECK_SHELL=bash
+
+# Enable strict mode
+export SHELLCHECK_STRICT=true
+
+# Specify configuration file location
+export SHELLCHECK_CONFIG=~/.shellcheckrc
+```
+
+## Common ShellCheck Error Codes
+
+### SC1000-1099: Parser Errors
+```bash
+# SC1004: Backslash continuation not followed by newline
+echo hello\
+world  # Error - needs line continuation
+
+# SC1008: Invalid data for operator `=='
+if [[ $var =  "value" ]]; then  # Space before ==
+    true
+fi
+```
+
+### SC2000-2099: Shell Issues
+
+```bash
+# SC2009: Consider using pgrep or pidof instead of grep|grep
+ps aux | grep -v grep | grep myprocess  # Use pgrep instead
+
+# SC2012: Use `ls` only for viewing. Use `find` for reliable output
+for file in $(ls -la)  # Better: use find or globbing
+
+# SC2015: Avoid using && and || instead of if-then-else
+[[ -f "$file" ]] && echo "found" || echo "not found"  # Less clear
+
+# SC2016: Expressions don't expand in single quotes
+echo '$VAR'  # Literal $VAR, not variable expansion
+
+# SC2026: This word is non-standard. Set POSIXLY_CORRECT
+# when using with scripts for other shells
+```
+
+### SC2100-2199: Quoting Issues
+
+```bash
+# SC2086: Double quote to prevent globbing and word splitting
+for i in $list; do  # Should be: for i in $list or for i in "$list"
+    echo "$i"
+done
+
+# SC2115: Literal tilde in path not expanded. Use $HOME instead
+~/.bashrc  # In strings, use "$HOME/.bashrc"
+
+# SC2181: Check exit code directly with `if`, not indirectly in a list
+some_command
+if [ $? -eq 0 ]; then  # Better: if some_command; then
+
+# SC2206: Quote to prevent word splitting or set IFS
+array=( $items )  # Should use: array=( $items )
+```
+
+### SC3000-3999: POSIX Compliance Issues
+
+```bash
+# SC3010: In POSIX sh, use 'case' instead of 'cond && foo'
+[[ $var == "value" ]] && do_something  # Not POSIX
+
+# SC3043: In POSIX sh, use 'local' is undefined
+function my_func() {
+    local var=value  # Not POSIX in some shells
+}
+```
+
+## Practical Configuration Examples
+
+### Minimal Configuration (Strict POSIX)
+
+```bash
+#!/bin/bash
+# Configure for maximum portability
+
+shellcheck \
+  --shell=sh \
+  --external-sources \
+  --check-sourced \
+  script.sh
+```
+
+### Development Configuration (Bash with Relaxed Rules)
+
+```bash
+#!/bin/bash
+# Configure for Bash development
+
+shellcheck \
+  --shell=bash \
+  --exclude=SC1091,SC2119 \
+  --enable=all \
+  script.sh
+```
+
+### CI/CD Integration Configuration
+
+```bash
+#!/bin/bash
+set -Eeuo pipefail
+
+# Analyze all shell scripts and fail on issues
+find . -type f -name "*.sh" | while read -r script; do
+    echo "Checking: $script"
+    shellcheck \
+        --shell=bash \
+        --format=gcc \
+        --exclude=SC1091 \
+        "$script" || exit 1
+done
+```
+
+### .shellcheckrc for Project
+
+```
+# Shell dialect to analyze against
+shell=bash
+
+# Enable optional checks
+enable=avoid-nullary-conditions,require-variable-braces,check-unassigned-uppercase
+
+# Disable specific warnings
+# SC1091: Not following sourced files (many false positives)
+disable=SC1091
+
+# SC2119: Use function_name instead of function_name -- (arguments)
+disable=SC2119
+
+# External files to source for context
+external-sources=true
+```
+
+## Integration Patterns
+
+### Pre-commit Hook Configuration
+
+```bash
+#!/bin/bash
+# .git/hooks/pre-commit
+
+#!/bin/bash
+set -e
+
+# Find all shell scripts changed in this commit
+git diff --cached --name-only | grep '\.sh$' | while read -r script; do
+    echo "Linting: $script"
+
+    if ! shellcheck "$script"; then
+        echo "ShellCheck failed on $script"
+        exit 1
+    fi
+done
+```
+
+### GitHub Actions Workflow
+
+```yaml
+name: ShellCheck
+
+on: [push, pull_request]
+
+jobs:
+  shellcheck:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Run ShellCheck
+        run: |
+          sudo apt-get install shellcheck
+          find . -type f -name "*.sh" -exec shellcheck {} \;
+```
+
+### GitLab CI Pipeline
+
+```yaml
+shellcheck:
+  stage: lint
+  image: koalaman/shellcheck-alpine
+  script:
+    - find . -type f -name "*.sh" -exec shellcheck {} \;
+  allow_failure: false
+```
+
+## Handling ShellCheck Violations
+
+### Suppressing Specific Warnings
+
+```bash
+#!/bin/bash
+
+# Disable warning for entire line
+# shellcheck disable=SC2086
+for file in $(ls -la); do
+    echo "$file"
+done
+
+# Disable for entire script
+# shellcheck disable=SC1091,SC2119
+
+# Disable multiple warnings (format varies)
+command_that_fails() {
+    # shellcheck disable=SC2015
+    [ -f "$1" ] && echo "found" || echo "not found"
+}
+
+# Disable specific check for source directive
+# shellcheck source=./helper.sh
+source helper.sh
+```
+
+### Common Violations and Fixes
+
+#### SC2086: Double quote to prevent word splitting
+
+```bash
+# Problem
+for i in $list; do done
+
+# Solution
+for i in $list; do done  # If $list is already quoted, or
+for i in "${list[@]}"; do done  # If list is an array
+```
+
+#### SC2181: Check exit code directly
+
+```bash
+# Problem
+some_command
+if [ $? -eq 0 ]; then
+    echo "success"
+fi
+
+# Solution
+if some_command; then
+    echo "success"
+fi
+```
+
+#### SC2015: Use if-then instead of && ||
+
+```bash
+# Problem
+[ -f "$file" ] && echo "exists" || echo "not found"
+
+# Solution - clearer intent
+if [ -f "$file" ]; then
+    echo "exists"
+else
+    echo "not found"
+fi
+```
+
+#### SC2016: Expressions don't expand in single quotes
+
+```bash
+# Problem
+echo 'Variable value: $VAR'
+
+# Solution
+echo "Variable value: $VAR"
+```
+
+#### SC2009: Use pgrep instead of grep
+
+```bash
+# Problem
+ps aux | grep -v grep | grep myprocess
+
+# Solution
+pgrep -f myprocess
+```
+
+## Performance Optimization
+
+### Checking Multiple Files
+
+```bash
+#!/bin/bash
+
+# Sequential checking
+for script in *.sh; do
+    shellcheck "$script"
+done
+
+# Parallel checking (faster)
+find . -name "*.sh" -print0 | \
+    xargs -0 -P 4 -n 1 shellcheck
+```
+
+### Caching Results
+
+```bash
+#!/bin/bash
+
+CACHE_DIR=".shellcheck_cache"
+mkdir -p "$CACHE_DIR"
+
+check_script() {
+    local script="$1"
+    local hash
+    local cache_file
+
+    hash=$(sha256sum "$script" | cut -d' ' -f1)
+    cache_file="$CACHE_DIR/$hash"
+
+    if [[ ! -f "$cache_file" ]]; then
+        if shellcheck "$script" > "$cache_file" 2>&1; then
+            touch "$cache_file.ok"
+        else
+            return 1
+        fi
+    fi
+
+    [[ -f "$cache_file.ok" ]]
+}
+
+find . -name "*.sh" | while read -r script; do
+    check_script "$script" || exit 1
+done
+```
+
+## Output Formats
+
+### Default Format
+
+```bash
+shellcheck script.sh
+
+# Output:
+# script.sh:1:3: warning: foo is referenced but not assigned. [SC2154]
+```
+
+### GCC Format (for CI/CD)
+
+```bash
+shellcheck --format=gcc script.sh
+
+# Output:
+# script.sh:1:3: warning: foo is referenced but not assigned.
+```
+
+### JSON Format (for parsing)
+
+```bash
+shellcheck --format=json script.sh
+
+# Output:
+# [{"file": "script.sh", "line": 1, "column": 3, "level": "warning", "code": 2154, "message": "..."}]
+```
+
+### Quiet Format
+
+```bash
+shellcheck --format=quiet script.sh
+
+# Returns non-zero if issues found, no output otherwise
+```
+
+## Best Practices
+
+1. **Run ShellCheck in CI/CD** - Catch issues before merging
+2. **Configure for your target shell** - Don't analyze bash as sh
+3. **Document exclusions** - Explain why violations are suppressed
+4. **Address violations** - Don't just disable warnings
+5. **Enable strict mode** - Use `--enable=all` with careful exclusions
+6. **Update regularly** - Keep ShellCheck current for new checks
+7. **Use pre-commit hooks** - Catch issues locally before pushing
+8. **Integrate with editors** - Get real-time feedback during development
+
+## Resources
+
+- **ShellCheck GitHub**: https://github.com/koalaman/shellcheck
+- **ShellCheck Wiki**: https://www.shellcheck.net/wiki/
+- **Error Code Reference**: https://www.shellcheck.net/