Gruntfile.js using grunt-contrib-cssmin, grunt-contrib-watch, grunt-contrib-concat, grunt-contrib-clean, grunt-contrib-compass, grunt-contrib-uglify

Gruntfile.js

module.exports = function(grunt) {
  var pkg = grunt.file.readJSON('package.json');

  grunt.initConfig({

    //Concatenate JS files
    concat: {
      lib: {
        src: [
          'public_html/dev/lib/jquery.js',
          'public_html/dev/lib/jquery_easing_min.js'
        ],
          dest: 'public_html/js/lib/lib.js'
      },
      dev: {
        src: [
          'public_html/dev/script.js',
          'public_html/dev/hoge.js'
        ],
          dest: 'public_html/js/app.js'
      }
    },

    //compass
    compass: {
      dist: {
      	options: {
      		config: 'config.rb',
      		sassDir: 'sass',
      		cssDir: 'css',
      		imagesDir: 'img'
      	}
      },
      dev: {
      	options: {
      		config: 'config.rb',
      		sassDir: 'dir/sass',
      		cssDir: 'dir/css',
      		imagesDir: 'dir/img'
      	}
      }
    },

    //Minify CSS files
    cssmin: {
    	combine: {
    		files: {
    			'public_html/css/style.css': ['public_html/css/style.css']
    		}
    	}
    },

    //Minify JS files with UglifyJS
    uglify: {
    	lib: {
    		src: 'public_html/js/lib/lib.js',
    		dest: 'public_html/js/lib/lib.min.js'
    	},
    	dev: {
    		src: 'public_html/js/app.js',
    		dest: 'public_html/js/app.min.js'
    	}
    },

    //Clear files
    clean: [
    'public_html/js/lib/lib.js',
    'public_html/js/app.js'
    ],

    //Watcing files change
    watch: {
      js: {
      	files: [
      	  'public_html/dev/**/*.js'
      	],
      	  tasks: ['concat', 'uglify']
      },
      scss: {
      	files: [
      	  'public_html/sass/*.scss'
    	],
    	  tasks: 'compass:dist'
      },
      scss2: {
      	files: [
      	  'public_html/dir/sass/*.scss'
      	],
      	  tasks: 'compass:dev'
      }
    }
  });

  var taskName;
  for(taskName in pkg.devDependencies) {
  	if(taskName.substring(0, 6) == 'grunt-') {
  	  grunt.loadNpmTasks(taskName);
  	}
  }

  //deploy task, enter 'grunt deploy'
  grunt.registerTask('deploy', ['clean', 'cssmin']);

  //default task, enter 'grunt'
  grunt.registerTask('default', ['watch', 'concat',  'compass', 'uglify']);
};