node.js开发中使用Node Supervisor实现监测文件修改并自动重启应用的功能，严重影响开发效率，因为Node.js只有在第一次引用到某部份时才会去解析脚本文件，以后都会直接访问内存，避免重复载入，提高性能。

安装 supervisor

npm install -g supervisor

这里需要特别说明的是，-g 意味着安装到全局，所以Linux和Mac系统在安装时，要加 sudo：

sudo npm install -g supervisor

基本使用

最常用、最快捷的方式，就是直接进入你的网站根目录，执行：

supervisor myapp

举个例子，Express4.0中，启动文件位于 ./bin/www 中，则我们启动时，必须在 ./ 中执行：

supervisor bin/www

而不能进入 bin 目录执行： supervisor www。这样虽然有可能也能启动，但这么做相当于把 bin 目录当作了服务的根目录了，一旦有涉及到文件目录的操作，一定会出错的。

更多使用方法

在命令行中直接执行：

supervisor 

会得到它的详细使用方法：

Node Supervisor is used to restart programs when they crash.
It can also be used to restart programs when a *.js file changes.

Usage:
  supervisor [options] <program>
  supervisor [options] -- <program> [args ...]

Required:
  <program>
    The program to run.

Options:
  -w|--watch <watchItems>
    A comma-delimited list of folders or js files to watch for changes.
    When a change to a js file occurs, reload the program
    Default is '.'

  -i|--ignore <ignoreItems>
    A comma-delimited list of folders to ignore for changes.
    No default

  --ignore-symlinks
    Enable symbolic links ignoring when looking for files to watch.

  -p|--poll-interval <milliseconds>
    How often to poll watched files for changes.
    Defaults to Node default.

  -e|--extensions <extensions>
    Specific file extensions to watch in addition to defaults.
    Used when --watch option includes folders
    Default is 'node,js'

  -x|--exec <executable>
    The executable that runs the specified program.
    Default is 'node'

  --debug[=port]
    Start node with --debug flag.

  --debug-brk[=port]
    Start node with --debug-brk[=port] flag.

  --harmony
    Start node with --harmony flag.

  --harmony_default_parameters
    Start node with --harmony_default_parameters flag.

  -n|--no-restart-on error|exit
    Don't automatically restart the supervised program if it ends.
    Supervisor will wait for a change in the source files.
    If "error", an exit code of 0 will still restart.
    If "exit", no restart regardless of exit code.
    If "success", no restart only if exit code is 0.
    
  -t|--non-interactive
    Disable interactive capacity.
    With this option, supervisor won't listen to stdin.

  -k|--instant-kill
    use SIGKILL (-9) to terminate child instead of the more gentle SIGTERM.

  --force-watch
    Use fs.watch instead of fs.watchFile.
    This may be useful if you see a high cpu load on a windows machine.

  -h|--help|-?
    Display these usage instructions.

  -q|--quiet
    Suppress DEBUG messages

  -V|--verbose
    Show extra DEBUG messages

Options available after start:
rs - restart process.
     Useful for restarting supervisor eaven if no file has changed.

Examples:
  supervisor myapp.js
  supervisor myapp.coffee
  supervisor -w scripts -e myext -x myrunner myapp
  supervisor -- server.js -h host -p port

如果想不监控某一些文件夹，可以使用 -i 参数。如：我们要忽略根目录下的 private 文件夹，可以这样启动：

supervisor -i ./private myapp

如果要忽略多个文件夹，则用英文的逗号,分隔：

supervisor -i ./private,./otherdir myapp