forever

⚠️ Community-maintained: The forever maintainer recommends pm2 or nodemon for new installations.

# Recommended alternatives for new projects
npm install -g pm2      # Production (clustering, load balancing)
npm install -g nodemon  # Development (auto-restart)

# Global installation (CLI)
npm install -g forever

# Local installation (programmatic use)
npm install forever-monitor

# Start a Node.js script as daemon
forever start app.js

# List running processes
forever list

# Stop a process
forever stop app.js

# View logs
forever logs 0

# Start with full logging
forever start \
  -l forever.log \
  -o out.log \
  -e err.log \
  -a \
  app.js

This starts app.js as a daemon with:

• Forever output logged to forever.log
• stdout logged to out.log
• stderr logged to err.log
• Append mode enabled (-a)

# Limit restart attempts to 5
forever start -m 5 app.js

# Require 10s uptime before considering stable
forever start --minUptime 10000 app.js

# Wait 5s between restart attempts
forever start --spinSleepTime 5000 app.js

# Full logging with append
forever start \
  -l logs/forever.log \
  -o logs/out.log \
  -e logs/err.log \
  -a \
  app.js

# Auto-restart on file changes (development)
forever start -w app.js

# Watch specific directory
forever start -w --watchDirectory ./src app.js

# Ignore node_modules
forever start -w --watchIgnore 'node_modules/**' app.js

# Run Python script
forever start -c python script.py

# Custom forever files location
forever start -p /var/run/forever app.js

# Graceful shutdown with SIGTERM
forever start --killSignal=SIGTERM app.js

# Kill entire process tree
forever start -t app.js

{
  "uid": "app",
  "append": true,
  "watch": true,
  "script": "app.js",
  "sourceDir": "/home/user/myapp",
  "logFile": "logs/forever.log",
  "outFile": "logs/out.log",
  "errFile": "logs/err.log"
}

# Start from config
forever start config.json

[
  {
    "uid": "api",
    "append": true,
    "watch": false,
    "script": "api/server.js",
    "sourceDir": "/home/user/apps",
    "logFile": "logs/api-forever.log",
    "outFile": "logs/api-out.log",
    "errFile": "logs/api-err.log"
  },
  {
    "uid": "worker",
    "append": true,
    "watch": false,
    "script": "worker/index.js",
    "sourceDir": "/home/user/apps",
    "logFile": "logs/worker-forever.log",
    "outFile": "logs/worker-out.log",
    "errFile": "logs/worker-err.log"
  }
]

# Start all apps from config
forever start config.json

const forever = require("forever-monitor");

const child = new forever.Monitor("app.js", {
  max: 3,
  silent: false,
  args: ["--port", "3000"],
});

child.on("exit", function () {
  console.log("app.js has exited after 3 restarts");
});

child.start();

const child = new forever.Monitor("app.js");

// Process started
child.on("start", function () {
  console.log("Process started");
});

// Process stopped
child.on("stop", function () {
  console.log("Process stopped");
});

// Process restarted
child.on("restart", function () {
  console.log("Process restarted");
});

// Process exited (max restarts reached)
child.on("exit", function () {
  console.log("Process exited");
});

// stdout data
child.on("stdout", function (data) {
  console.log("stdout:", data.toString());
});

// stderr data
child.on("stderr", function (data) {
  console.error("stderr:", data.toString());
});

child.start();

const forever = require("forever-monitor");

// Run Python script
const child = new forever.Monitor("script.py", {
  command: "python",
  args: ["--verbose"],
});

child.start();

const child = new forever.Monitor("app.js", {
  max: 10, // Max restart attempts
  silent: false, // Log to console
  minUptime: 5000, // 5s min uptime
  spinSleepTime: 2000, // 2s between restarts
  killTree: true, // Kill child processes
  killSignal: "SIGTERM", // Graceful shutdown
  watch: true, // Watch file changes
  watchDirectory: "./src", // Watch directory
  watchIgnoreDotFiles: true, // Ignore dotfiles
  env: {
    // Environment variables
    NODE_ENV: "production",
  },
  cwd: "/app", // Working directory
  logFile: "logs/forever.log",
  outFile: "logs/out.log",
  errFile: "logs/err.log",
  append: true,
});

child.start();

# Full logging, limited restarts, graceful shutdown
forever start \
  -l /var/log/myapp/forever.log \
  -o /var/log/myapp/out.log \
  -e /var/log/myapp/err.log \
  -a \
  -m 10 \
  --minUptime 10000 \
  --spinSleepTime 5000 \
  --killSignal=SIGTERM \
  /app/server.js

# Watch files, unlimited restarts
forever start \
  -w \
  --watchDirectory ./src \
  --watchIgnore 'node_modules/**' \
  -a \
  app.js

# Use nvm node version
forever start \
  -c /home/user/.nvm/versions/node/v16.20.0/bin/node \
  app.js

# Pass arguments to script
forever start app.js -- --port 8080 --env production

# Pass arguments with options
forever start -a -l logs/forever.log app.js -- --port 8080

# Python script
forever start -c python script.py

# Ruby script
forever start -c ruby script.rb

# With arguments
forever start -c python script.py -- --verbose --config config.yml

# Start with unique IDs
forever start --uid "api" api/server.js
forever start --uid "worker" worker/index.js

# List with UIDs
forever list

# Stop by UID
forever stop api
forever stop worker

# Default forever root
~/.forever/

# Log structure
~/.forever/
  ├── forever.log        # Forever daemon output
  ├── <uid>.log          # Per-process logs
  ├── <uid>.out          # stdout
  └── <uid>.err          # stderr

# Set FOREVER_ROOT environment variable
export FOREVER_ROOT=/var/log/forever

# Start with custom location
forever start app.js

# Logs now in
/var/log/forever/

# List all log files
forever logs

# Tail logs for process 0
forever logs 0

# Tail logs by script name
forever logs app.js

# Tail logs by UID
forever logs myapp

# Delete all historical logs
forever cleanlogs

# Clean logs then start fresh
forever cleanlogs && forever start -a app.js

# Rotate logs manually (stops all processes!)
forever stopall
forever cleanlogs
forever start config.json

# Use system log rotation (logrotate)
# /etc/logrotate.d/forever
/var/log/myapp/*.log {
    daily
    rotate 7
    compress
    delaycompress
    missingok
    notifysempty
    copytruncate
}

# Change location of forever files
export FOREVER_ROOT=/var/run/forever

# Default location
~/.forever/

#!/bin/bash
export FOREVER_ROOT=/var/log/forever
export NODE_ENV=production

forever start \
  -a \
  -l forever.log \
  -o out.log \
  -e err.log \
  app.js

# From forever to pm2 (production)
forever stop app.js
pm2 start app.js -i max  # Cluster mode with max CPUs

# From forever to nodemon (development)
forever stop app.js
nodemon app.js

Problem: Process crashes within minUptime and stops restarting.

# Increase minUptime threshold
forever start --minUptime 5000 app.js

# Increase wait time between restarts
forever start --spinSleepTime 3000 app.js

# Unlimited restarts (not recommended)
forever start -m -1 app.js

Problem: Log files empty or not created.

# Ensure append flag is set
forever start -a -l logs/forever.log app.js

# Check file permissions
ls -la logs/

# Verify FOREVER_ROOT
echo $FOREVER_ROOT
forever list

Problem: forever stop doesn't kill process.

# Use killTree to kill child processes
forever start -t app.js

# Use SIGTERM for graceful shutdown
forever start --killSignal=SIGTERM app.js

# Force stop all
forever stopall

# Nuclear option: kill by PID
forever list  # Get PID
kill -9 <PID>

Problem: Changes not triggering restart.

# Specify watch directory explicitly
forever start -w --watchDirectory ./src app.js

# Ignore problematic directories
forever start -w --watchIgnore 'node_modules/**' app.js

# Check if file is in watched directory
forever list  # Shows watch config

Problem: Process stops after max restarts.

# Check logs for crash reason
forever logs app.js

# Fix issue, then restart
forever start app.js

# Increase max restarts (temporary)
forever start -m 100 app.js

Problem: Old processes still running after stopall.

# Clean slate
forever stopall
forever cleanlogs
ps aux | grep node  # Verify no orphans

# Restart fresh
forever start config.json