Execute tasks when CLI output patterns are detected
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Features • Installation • Usage • Examples
A lightweight Node.js CLI tool that monitors command output in real-time and triggers actions when specific patterns are found. Perfect for automation workflows, development environments, and CI/CD pipelines.
- 🎯 Pattern Matching - Monitor stdout/stderr for regex patterns or plain strings
- ⚡ Real-time Monitoring - Output is forwarded in real-time while monitoring
- 🔧 Flexible Actions - Display messages or execute commands when patterns match
- 📝 Multiple Patterns - Wait for multiple patterns before triggering actions
- 🚀 Zero Dependencies - Built with Node.js built-in modules only
npm install -g run-on-outputOr use without installing:
npx run-on-output [options] <command> [args...]Display a message when server starts:
run-on-output -s "Server started" -m "🚀 Server is ready" npm startExecute a health check when server is listening:
run-on-output -p "listening on port \\d+" -r "curl http://localhost:3000/health" node server.jsMonitor development environment startup:
run-on-output -s "webpack compiled,server ready" -m "✅ Development environment ready" npm run devMultiple actions - show message and open browser:
run-on-output -s "ready" -m "Server is up" -r "open http://localhost:3000" npm startRun npm script when server is ready:
run-on-output -s "Server running" -n "test" node server.jsTip
You can use the short alias roo instead of run-on-output for faster typing:
roo -s "Server started" -m "🚀 Server is ready" npm startrun-on-output [OPTIONS] <command> [args...]
OPTIONS:
-p, --patterns <patterns> Comma-separated list of regex patterns to watch for
-s, --strings <strings> Comma-separated list of plain strings to watch for
-r, --run <command> Command to execute after all patterns are found
-n, --npm <script> npm script to run after all patterns are found
-m, --message <text> Message to display after all patterns are found
-h, --help Show this help message
REQUIREMENTS:
- Either --patterns or --strings must be specified (but not both)
- At least one of --run, --npm, or --message must be specified
Plain Strings (-s, --strings)
- Matches exact text (case-insensitive)
- Easier to use for simple text matching
- Example:
-s "Server started,Database connected"
Regex Patterns (-p, --patterns)
- Use regular expressions for complex matching
- Supports all JavaScript regex features
- Example:
-p "listening on port \\d+,ready in \\d+ms"
Development Workflow
# Wait for both webpack and server, then open browser
run-on-output -s "webpack compiled,Local:" -r "open http://localhost:3000" npm run dev
# Monitor test runner and show completion message
run-on-output -s "Tests completed" -m "✅ All tests passed" npm testCI/CD Pipeline
# Wait for deployment completion and run smoke tests
run-on-output -p "deployment.*complete" -r "./scripts/smoke-test.sh" deploy.sh
# Monitor build process and trigger notifications
run-on-output -s "Build successful" -r "slack-notify '#dev' 'Build completed'" npm run buildDocker & Containers
# Wait for container health check and run integration tests
run-on-output -s "healthy" -r "npm run test:integration" docker-compose up
# Monitor database initialization
run-on-output -p "database.*ready" -m "📁 Database initialized" ./start-db.shAPI Development
# Wait for API server and run endpoint tests
run-on-output -p "server.*listening.*port" -r "npm run test:api" node api.js
# Monitor microservices startup and run deployment script
run-on-output -s "auth-service ready,user-service ready" -n "deploy" ./start-services.sh
# Combine message, command and npm script
run-on-output -s "Database connected" -m "🎉 Ready for testing" -n "test:integration" npm start