How to use the gulp.dest function in gulp

])
  .pipe($.angularFilesort()).on('error', errorHandler('AngularFilesort'));

  // make the path relative
  var injectOptions = {
    ignorePath: [path.join(options.paths.src, 'app'), options.paths.tmp],
    addRootSlash: false
  };

  return gulp.src(path.join(options.paths.src, '*.html'))
    .pipe(injectCSP())                        // inject:csp
    .pipe(injectAppInfo())                    // inject:appinfo
    .pipe($.inject(cssFiles, injectOptions))  // inject:css
    .pipe($.inject(jsFiles, injectOptions))   // inject:js
    .pipe(wiredep())                          // bower:css
    .pipe(gulp.dest(options.paths.tmp));

  /* Important: While using both, `wiredep` should always run after `inject` in the pipe */
});

var stream = gulp
            // Write the revisioned files
            .src([].concat(minified, index)) // add all staged min files and index.html
            .pipe(minFilter) // filter the stream to minified css and js
            .pipe(plug.rev()) // create files with rev's
            .pipe(gulp.dest(pkg.paths.stage)) // write the rev files
            .pipe(minFilter.restore()) // remove filter, back to original stream

            // inject the files into index.html
            .pipe(indexFilter) // filter to index.html
            .pipe(inject('content/vendor.min.css', 'inject-vendor'))
            .pipe(inject('content/all.min.css'))
            .pipe(inject('vendor.min.js', 'inject-vendor'))
            .pipe(inject('all.min.js'))
            .pipe(gulp.dest(pkg.paths.stage)) // write the rev files
            .pipe(indexFilter.restore()) // remove filter, back to original stream

            // replace the files referenced in index.html with the rev'd files
            .pipe(plug.revReplace())         // Substitute in new filenames
            .pipe(gulp.dest(pkg.paths.stage)) // write the index.html file changes
            .pipe(plug.rev.manifest()) // create the manifest (must happen last or we screw up the injection)
            .pipe(gulp.dest(pkg.paths.stage)); // write the manifest

        function inject(path, name) {
            var glob = pkg.paths.stage + path;
            var options = {
                ignorePath: pkg.paths.stage.substring(1),
                read: false
            };
            if (name) { options.name = name; }
            return plug.inject(gulp.src(glob), options);

gulp.task('buildBundle', ['styles', 'buildScripts'], function () {
  return gulp.src('./app/index.html')
    .pipe($.useref.assets())
    .pipe($.useref.restore())
    .pipe($.useref())
    .pipe(gulp.dest('dist/public'))
})

var bump = function(type) {
  gulp.src(['./bower.json', './package.json'])
    .pipe(gbump({type: type}))
    .pipe(gulp.dest('./'));
};

gulp.task('polyfill', () => {
  gulp.src('app/scripts/polyfill.js')
    .pipe(gulp.dest('dist/scripts'))
    .pipe(uglify())
    .pipe(rename('polyfill.min.js'))
    .pipe(gulp.dest('app/scripts'));
});

gulp.task("compile-jade", function () {
    gulp.src(["src/**/*.jade", "!./src/includes/**/*.*"])
        .pipe(plumber())
        .pipe(jade({locals: require('./src/context')}))
        .pipe(gulp.dest("httpdocs"))
        .pipe(connect.reload());
});

gulp.task('image', function(){
  gulp.src('src/img/**')
    .pipe(imagemin({
        progressive: true,
        svgoPlugins: [{removeViewBox: false}],
        use: [pngquant()]
    }))
    .pipe(gulp.dest('dist/img'));
  gulp.src('src/sound/**')
    .pipe(gulp.dest('dist/sound'));
  gulp.src('src/fonts/**')
    .pipe(gulp.dest('dist/fonts'));
});

gulp.task("build-images-backgrounds", function () {

        return gulp.src([
            "src/images/bg/*.{jpg,jpeg}"
        ])
                .pipe(imageResize({
                    width: 4096,
                    quality: 0.8,
                    format: "jpg"
                }))
                .pipe(gulpif(PRODUCTION, imageop({
                    optimizationLevel: 5,
                    progressive: true,
                    interlaced: true
                })))
                .pipe(gulp.dest("Server/web/images/bg"));
    });

.pipe(cssFilter.restore)
        .pipe(assets.restore())
        .pipe($.useref())
        .pipe($.revReplace())
        .pipe(htmlFilter)
        .pipe($.minifyHtml({
            empty: true,
            spare: true,
            quotes: true,
            conditionals: true
        }))
        .pipe(htmlFilter.restore)
        .pipe(htmlIndexFilter)
        .pipe($.header(licences.html, {year: new Date().getFullYear()}))
        .pipe(htmlIndexFilter.restore)
        .pipe(gulp.dest(path.join(conf.paths.dist, '/')))
        .pipe($.size({title: path.join(conf.paths.dist, '/'), showFiles: true}));
}

gulp.task('images:optimize', () => {

  let options = {
    progressive: true,
    svgoPlugins: [{
      removeViewBox: false
    }]
    //, use: [pngquant()]
  };

  gulp
    .src(paths.images)
    .pipe(imagemin(options))
    .pipe(gulp.dest(`${paths.images}/opt`));

});