咕嚕文件失敗'由於警告而中止'

我是Grunt的新手。我想我會試試看，所以我創建了這個咕嚕聲文件。咕嚕文件失敗'由於警告而中止'

module.exports = function(grunt) { 

    grunt.initConfig({ 

     pkg: grunt.file.readJSON('package.json'), 

     concat: { 
      css: { 
       src: [ 
        './css/*' 
       ], 
       dest: './css/all.css' 
      }, 
      js: { 
       src: [ 
        './js/*' 
       ], 
       dest: './js/all.js' 
      } 
     }, 

     uglify: { 
      js: { 
       files: { 
        './js/build/all.min.js': ['./js/all.js'] 
       } 
      } 
     }, 

     sass: { 
      build: { 
       files: [{ 
        expand: true, 
        cwd: './css/sass', 
        src: ['*.scss'], 
        dest: './css', 
        ext: '.css' 
       }] 
      } 
     }, 

     cssmin: { 
      css: { 
       src: './css/all.css', 
       dest: './css/build/all.min.css' 
      } 
     }, 

     watch: { 
      files: ['./css/sass/*', './js/*'], 
      tasks: ['sass:build','concat:css', 'cssmin:css', 'concat:js', 'uglify:js'] 
     } 

    }); 

    grunt.loadNpmTasks('grunt-contrib-uglify'); 
    grunt.loadNpmTasks('grunt-contrib-watch'); 
    grunt.loadNpmTasks('grunt-contrib-sass'); 
    grunt.loadNpmTasks('grunt-contrib-cssmin'); 
    grunt.loadNpmTasks('grunt-contrib-concat'); 

    grunt.registerTask('dev', ['sass:build','concat:css', 'cssmin:css', 'concat:js', 'uglify:js']); 

};

當我運行'grunt watch'並對.scss文件進行更改時，終端抱怨然後終止。

Running "watch" task 
Waiting... 
>> File "css/sass/all.scss" changed. 
Running "sass:build" (sass) task 
File css/all.css created. 

Running "concat:css" (concat) task 
Warning: Unable to read "./css/build" file (Error code: EISDIR). Use --force to continue. 

Aborted due to warnings. 
Completed in 1.276s at Thu May 01 2014 23:53:59 GMT+0100 (BST) - Waiting...

請有人指出我要去哪裏錯了嗎？

它看起來與concat:css-但沒有參考建立目錄那裏。

我認爲這可能是因爲某些任務正在發生碰撞，並且文件尚未準備好，可能還沒有準備好？有任務的訂單嗎？

請耐心等待，因爲它是全新的！

謝謝，邁克爾。

來源

2014-05-01 Michael Giovanni Pumo