This is an example of a Grunt build task from https://github.com/yeoman/grunt-usemin/issues/176#issuecomment-24361368 that copies over a file with replaced references and stashes them into a build directory for production.

grunt-use-min.js

module.exports = function (grunt) {
  grunt.initConfig({
    clean: ['build'],
    copy: {
      html: { // in preparation for usemin
        files: [
          {src: 'index.html', dest: 'build/'}
        ]
      }
    }, 
    uglify: {
      all: {
        files: {
          'build/output.min.js': ['lib/angular.min.js', 'scripts/*.js']
        }
      }
    },
    useminPrepare: {
      options: {dest: 'build'}
    },
    usemin: {
      html: 'build/index.html', // must have this
      //css: '*.css',
      options: {
        dirs: ['lib', 'scripts']
      }
    },
  });

  var tasks = [
    'grunt-contrib-clean',
    'grunt-contrib-copy',
    'grunt-contrib-cssmin',
    'grunt-contrib-uglify',
    'grunt-usemin'
  ];
  tasks.forEach(grunt.loadNpmTasks);

  grunt.registerTask('min', ['copy', 'useminPrepare', 'uglify', 'usemin']);
};

Do not take this as verbatim. Customize to your needs