gulpfile.js如下

var gulp    = require('gulp');
var less  = require('gulp-less');
var concat = require('gulp-concat');//文件合并
var minifycss = require('gulp-minify-css');
var rename = require('gulp-rename');//文件更名
var watch  = require('gulp-watch');

gulp.task('mergeHtml', function() {
  gulp.src('dist/example/*.html')
    .pipe(concat('index.html'))
    .pipe(gulp.dest('app/html'));
});


gulp.task('watch', function () {
    gulp.watch('dist/example/*.html', ['mergeHtml']);
}); 

gulp.task('default', ['watch']);