PM2 can automatically restart your app when a file changes in the current directory or its subdirectories:

$ pm2 start app.js --watch

If --watch is enabled, stopping it won't stop watching:

• pm2 stop 0 will not stop watching
• pm2 stop --watch 0 will stop watching

Restart toggle the watch parameter when triggered.

To watch specific paths, please use a JS/JSON app declaration, watch can take a string or an array of paths. Default is true:

{
  "watch": ["server", "client"],
  "ignore_watch" : ["node_modules", "client/img"],
  "watch_options": {
    "followSymlinks": false
  }
}

As specified in the Schema:

• watch can be a boolean, an array of paths or a string representing a path. Default to false
• ignore_watch can be an array of paths or a string, it'll be interpreted by chokidar as a glob or a regular expression.
• watch_options is an object that will replace options given to chokidar. Please refer to chokidar documentation for the definition.

PM2 is giving chokidar these Default options:

var watch_options = {
  persistent    : true,
  ignoreInitial : true
}

When working with NFS devices you'll need to set usePolling: true as stated in this chokidar issue.