grunt-pluginの作り方と解剖 ref: http://qiita.com/items/5590e7e92b4f2bd81d04

file0.txt

var grunt = require('grunt');

grunt.registerTask('sample', 'sample task', function () {
    console.log('this is sample task!');
});

file1.txt

% grunt sample
this is sample task!


file10.txt

var fs = require('fs');

module.exports = function (grunt) {
    grunt.registerTask('sample', 'sample task', function () {
        // 環境名の取得
        var target = this.target;

        // 非同期タスクにする(doneにcallback関数が入る)
        var done = grunt.async();

        // configから"filename"を取得
        var filename = grunt.config('sample')[target].filename;

        fs.readFile(filename, 'utf8', function (err, data) {
            // ファイルをreadするのを待って、出力したら終了
            console.log(data);
            done();
        });
    });
};

file9.txt

% grunt simple:dev
hogehoge
% grunt simple:prod
moge
% grunt simple
hogehoge
moge

Gruntfile.js

var grant = require('grunt');

module.exports = function () {
    grunt.initConfig({
        sample: {
            dev: { // 開発環境
                hoge: 'hogehoge'
            },
            prod: { // 本番環境
                hoge: 'moge'
            }
        }
    });  

    grunt.loadNpmTask('grunt-sample');
};

package.json

{
  "name": "grunt-sample",
  "version": "0.0.1",
  "description": "sample grunt plugin",
  "keywords": [
    "gruntplugin"
  ],
  "devDependencies": {
    "grunt": "~0.4.1"
  }
}

sample.js

module.exports = function (grunt) {
    grunt.registerTask('sample', 'sample task', function () {
        console.log('this is sample task!');
    });
};

simple.js

module.exports = function (grunt) {
    grunt.registerMultiTask('sample', 'sample task', function () {
        // 環境名の取得
        var target = this.target;

        // configから"hoge"を取得
        var hoge = grunt.config('sample')[target].hoge;
        console.log(hoge);
    });
};

ディレクトリ構成

grunt-sample
├── package.json
└── tasks
    └── sample.js