Section 2: CLI Automation & Scripting

Pre-Commit Hooks

Auto Code Review

#!/bin/bash
# .git/hooks/pre-commit

# Get staged files
STAGED=$(git diff --cached --name-only)

# Review with Claude
echo "$STAGED" | claude "Review for:
- console.log statements
- TODO without tickets
- Hardcoded credentials
Exit 1 if issues found"

exit $?

Anti-Pattern: Committing changes without any review automation
Better: Add pre-commit hooks that catch issues before they reach CI/CD
Why: Issues caught in pre-commit hooks take seconds to fix. Same issues in CI take 5-10 minutes or worse - reach production.

Auto-Format & Fix

#!/bin/bash
# .git/hooks/pre-commit

# Fix lint errors
npm run lint -- --fix

# Add fixed files
git add -u

# Review changes
git diff --cached | claude "Quick review of auto-fixes"

Anti-Pattern: No error handling in automation scripts
Better: Check exit codes, use set -e, add fallbacks
Why: Scripts without error handling silently fail in CI/CD. Always handle errors.

CI/CD Integration

GitHub Actions

name: Claude Code Review
on: [pull_request]
jobs:
  review:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - name: Install Claude CLI
        run: curl -fsSL https://claude.ai/install.sh | sh
      - name: Review PR
        env:
          ANTHROPIC_API_KEY: $
        run: |
          git diff origin/main... | \
          claude "Review for: security, performance, best practices"

What to check in AI-generated code: PR Review Guide.

Anti-Pattern: Using expensive Opus model in CI/CD for all checks
Better: Use Haiku for fast checks (linting, formatting), reserve Sonnet/Opus for security reviews
Why: CI runs dozens of times per day. Haiku is 10x faster and 60x cheaper. Use --model haiku-4.5 for speed.

GitLab CI

claude-review:
  script:
    - curl -fsSL https://claude.ai/install.sh | sh
    - git diff $CI_MERGE_REQUEST_DIFF_BASE_SHA... | claude "Security review"

Batch Operations

Multi-File Processing

#!/bin/bash
# process-all-tests.sh

find tests/ -name "*.test.js" | while read file; do
  claude "Add missing edge case tests to $file" \
    --output "$file"
done

Anti-Pattern: Sequential file operations (slow - waits for each file)
Better: Use parallel processing: xargs -P 4 or GNU parallel for batch operations
Why: Processing 100 files sequentially takes 100x time. Parallel processing achieves 4-10x speedup.

Parallel Processing

#!/bin/bash
# parallel-review.sh

find src/ -name "*.js" | \
  xargs -P 4 -I {} bash -c 'claude "Review {}" > {}.review'

PowerShell Automation

Windows Automation

# auto-document.ps1

Get-ChildItem -Path src -Filter *.js -Recurse | ForEach-Object {
    $content = Get-Content $_.FullName -Raw
    $docs = $content | claude "Generate JSDoc comments"
    Set-Content -Path $_.FullName -Value $docs
}

Error Handling

Robust Scripts

#!/bin/bash
set -euo pipefail

# Function with error handling
claude_safe() {
    local output
    if output=$(claude "$@" 2>&1); then
        echo "$output"
        return 0
    else
        echo "Error: Claude CLI failed" >&2
        echo "$output" >&2
        return 1
    fi
}

# Usage
claude_safe "Review code" || exit 1

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