$ npm --version
1.3.11
$ pwd
/Users/cowboy/repos/gruntjs/grunt
$ cat package.json
{
  "name": "grunt",
  "version": "0.4.2-0",
  "repository": {
    "type": "git",
    "url": "git://github.com/gruntjs/grunt.git"
  },
  "devDependencies": {
    "grunt-contrib-copy": "*"
  }
}

$ rm -rf node_modules/
$ npm install grunt
npm WARN install Refusing to install grunt as a dependency of itself
$ npm install --silent grunt-contrib-copy
grunt-contrib-copy@0.4.1 node_modules/grunt-contrib-copy
$ tree -L 1 node_modules/
node_modules/
└── grunt-contrib-copy
1 directory, 0 files

$ rm -rf node_modules/
$ npm install --silent
grunt@0.4.1 node_modules/grunt
├── which@1.0.5
├── dateformat@1.0.2-1.2.3
├── eventemitter2@0.4.13
├── colors@0.6.2
├── hooker@0.2.3
├── async@0.1.22
├── coffee-script@1.3.3
├── underscore.string@2.2.1
├── iconv-lite@0.2.11
├── lodash@0.9.2
├── findup-sync@0.1.2 (lodash@1.0.1)
├── nopt@1.0.10 (abbrev@1.0.4)
├── rimraf@2.0.3 (graceful-fs@1.1.14)
├── minimatch@0.2.12 (sigmund@1.0.0, lru-cache@2.3.1)
├── glob@3.1.21 (inherits@1.0.0, graceful-fs@1.2.3)
└── js-yaml@2.0.5 (esprima@1.0.4, argparse@0.1.15)
grunt-contrib-copy@0.4.1 node_modules/grunt-contrib-copy
$ tree -L 1 node_modules/
node_modules/
├── grunt
└── grunt-contrib-copy
2 directories, 0 files