# forever — Keep Node.js Scripts Running Continuously

> A CLI tool that ensures a given Node.js script runs continuously, restarting it on failure.

## Install

Save in your project root:

# forever — Keep Node.js Scripts Running Continuously

## Quick Use
```bash
npm install -g forever
forever start app.js
forever list
forever stop app.js
```

## Introduction
forever is a Node.js CLI tool and library that keeps your scripts running continuously. If a process crashes or exits unexpectedly, forever automatically restarts it, making it a straightforward solution for keeping Node.js services alive in production or development environments without complex orchestration.

## What forever Does
- Starts Node.js scripts as background daemon processes
- Automatically restarts scripts when they crash or exit
- Provides listing, stopping, and log management for running processes
- Supports custom environment variables and command-line arguments per process
- Can run as both a CLI tool and a programmatic Node.js module

## Architecture Overview
forever uses a monitor/worker pattern. The CLI spawns a monitor process that watches the child script. When the child exits, the monitor evaluates the exit code and restart policy, then re-spawns if appropriate. Each managed process gets its own log files for stdout and stderr. The monitor communicates over IPC to the CLI for commands like list, stop, and restart. A shared socket file tracks all active forever processes on the system.

## Self-Hosting & Configuration
- Install globally: `npm install -g forever`
- Start a script: `forever start --minUptime 1000 --spinSleepTime 1000 app.js`
- Set custom log output: `forever start -o out.log -e err.log app.js`
- Use a JSON config file for multiple processes: `forever start forever.json`
- Set the `--uid` flag to give processes a unique identifier for management

## Key Features
- Zero-downtime restarts with configurable minimum uptime thresholds
- Per-process log file management with rotation support
- JSON-based configuration for managing multiple processes
- Programmatic API for embedding in custom deployment scripts
- Spin-sleep delay to prevent rapid restart loops on persistent failures

## Comparison with Similar Tools
- **PM2** — more feature-rich with clustering, metrics, and a dashboard; forever is simpler and lighter
- **nodemon** — restarts on file changes during development; forever restarts on crashes in production
- **systemd** — OS-level service manager; forever is Node.js-specific and easier to set up for Node apps
- **Docker restart policies** — container-level restarts; forever works inside or outside containers

## FAQ
**Q: How do I see all running forever processes?**
A: Run `forever list` to see process IDs, uptimes, and log file locations.

**Q: Can I limit how many times a script restarts?**
A: Yes. Use `--max` to set a maximum restart count: `forever start --max 5 app.js`.

**Q: Does forever support clustering?**
A: No. For clustering, consider PM2 or use the Node.js cluster module directly. forever focuses on single-process monitoring.

**Q: Can I use forever with non-Node scripts?**
A: Yes. Use `forever start -c python my_script.py` with the `-c` flag to specify the command interpreter.

## Sources
- https://github.com/foreversd/forever
- https://github.com/foreversd/forever/blob/master/README.md

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Source: https://tokrepo.com/en/workflows/asset-118e56f4
Author: AI Open Source