Convert Gulp task to Webpack

I am unsure what you are asking. Do you have a gulp config you wish to setup in webpack so it does the same?

If so you should post the config. Maybe someone can give you some pointers.

If not, then please give an example of what you are trying to accomplish

Yeah I'm wanting to recreate this gulp task in webpack.

gulp.task('prefix', function(done) {
    var prefix = gutil.env.p || gutil.env.prefix || false;

    if(!prefix) {
        return done();
    }

    gutil.log("Replacing prefix 'uk' with '"+prefix+"'");

    gulp.src(['./dist/**/*.css', './dist/**/*.less', './dist/**/*.scss', './dist/**/*.js'])
        .pipe(replace(/(uk-([a-z\d\-]+))/g, prefix+'-'))
        .pipe(replace(/data-uk-/g, 'data-'+prefix+'-'))
        .pipe(replace(/UIkit2/g, 'UIkit2'+prefix))
        .pipe(gulp.dest('./dist'))
        .on('end', done);
});