Gruntfile.js

"use strict";
module.exports = function(grunt) {

  // Override process.stdout to log the name+args of the current task before
  // every logged line.
  var hooker = require('hooker');
  var newline = true;

  hooker.hook(process.stdout, 'write', function(str) {
    var prefix = grunt.task.current.nameArgs;

    //I want to check for logFile here.

    if (newline && prefix && str !== '\n') {

      newline = false;
      str = '[' + prefix + '] ' + str;
    }

    newline = /\n/.test(str);

    return hooker.filter(this, [str]);
  });

  // Project configuration.
  grunt.initConfig({
    pkg: grunt.file.readJSON('package.json'),
    uglify: {
      options: {
        banner: '/*! <%= pkg.name %> <%= grunt.template.today("yyyy-mm-dd-hh:MM:ss") %> v<%= pkg.version %> */\n'
      },
      build: {
        expand: true,
        cwd: 'js/raw',
        src: '**/*.js',
        dest: 'js/min/',
        ext: '.js'

      },
      logFile : 'uglify.log'
    },
  });

  // Load the plugin that provides the "uglify" task.
  grunt.loadNpmTasks('grunt-contrib-uglify');
  
  // Default task(s).
  grunt.registerTask('default', ['uglify']);

};

var fs = require('fs');
var hooker = require('hooker');
hooker.hook(process.stdout, 'write', function(str) {
  var filename = grunt.task.current.nameArgs;
  if (filename) {
    filename = 'log-' + filename.replace(/:/g, '-') + '.txt';
    fs.appendFile(filename, grunt.log.uncolor(str));
  }
});