Basic Grunt setup

Gruntfile.js

module.exports = function(grunt) {
  require('jit-grunt')(grunt);
  
  grunt.initConfig({
    path: {
      'static': 'static',
      'src': 'src',
      'node': 'node_modules'
    },
    less: {
      options: {
        sourceMap: false
      },
      development: {
        options: {
          sourceMap: true,
          sourceMapFileInline: true
        },
        files: {
          '<%= path.static %>/css/main.css': '<%= path.src %>/less/main.less'
        }
      },
      production: {
        files: {
          '<%= path.static %>/css/main.css': '<%= path.src %>/less/main.less'
        }
      }
    },
    concat: {
      js: {
        src: [
          '<%= path.src %>/js/some.js',
          '<%= path.src %>/js/other.js'
        ],
        dest: '<%= path.static %>/js/main.js'
      }
    },
    watch: {
      options: {
        nospawn: true
      },
      less: {
        files: ['<%= path.src %>/less/**/*.less'],
        tasks: ['less:development']
      }
    }
  });
  
  grunt.registerTask('development', [
    'less:development',
    'concat:js'
  ]);

  grunt.registerTask('production', [
    'less:production',
    'concat:js'
  ]);

  grunt.registerTask('default', [
    'development',
    'watch'
  ]);
};

package.json

{
  "name": "Project name",
  "version": "0.0.1",
  "description": "Project description",
  "author": {
    "name": "Eau de Web",
    "email": "office@eaudeweb.ro",
    "url": "http://www.eaudeweb.ro/"
  },
  "dependencies": {
    "grunt": "^1.0.1",
    "grunt-contrib-concat": "~0.5.1",
    "grunt-contrib-less": "^1.0.1",
    "grunt-contrib-watch": "^0.6.1",
    "jit-grunt": "^0.9.1"
  }
}