$ npm install -g nrm

$ nrm ls

* npm -----  https://registry.npmjs.org/
  cnpm ----  http://r.cnpmjs.org/
  taobao --  https://registry.npm.taobao.org/
  nj ------  https://registry.nodejitsu.com/
  rednpm -- http://registry.mirror.cqupt.edu.cn
  skimdb -- https://skimdb.npmjs.com/registry

$ nrm use cnpm  //switch registry to cnpm

    Registry has been set to: http://r.cnpmjs.org/

Usage: nrm [options] [command]

  Commands:

    ls                           List all the registries
    use <registry>               Change registry to registry
    add <registry> <url> [home]  Add one custom registry
    del <registry>               Delete one custom registry
    home <registry> [browser]    Open the homepage of registry with optional browser
    test [registry]              Show the response time for one or all registries
    help                         Print this help

  Options:

    -h, --help     output usage information
    -V, --version  output the version number