gulpfile.js

var gulp = require('gulp');
	replace = require('gulp-replace');
	connect = require('gulp-connect');

gulp.task('hashReplace', function() {
    gulp.src(['src/index.html'])
        .pipe(replace('{{hash}}', guid()))
        .pipe(gulp.dest('./'));
});

gulp.task('serveprod', function() {
    connect.server({
    	root: ['/home/weslei/lixo/estudosgulp'],
    	fallback: 'index.html',
        port: process.env.PORT || 5000, // localhost:5000
        livereload: false
    });
});

gulp.task('watch', function () {
  gulp.watch(['*.html'], ['hashReplace']);
});


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

function guid() {
    function s4() {
        return Math.floor((1 + Math.random()) * 0x10000)
            .toString(16)
            .substring(1);
    }
    return s4() + s4() + s4() + s4() +
        s4() + s4() + s4() + s4();
}