$schemamarkup = get_post_meta(get_the_ID(), 'schemamarkup', true); if(!empty($schemamarkup)) { echo $schemamarkup; }

How to Get Started With Xinput on Gnu/Linux Distros

GNU/Linux Xinput QuickStart Guide

Hi! The linked Tutorials Show you Step-by-step How to Install and Getting Started with xinput Command Line Tool in GNU/Linux Desktops.

And xinput for GNU+Linux is a Utility to configure and test X input Devices, such as Mouses, Keyboards, and Touchpads

Most noteworthy this Guide make use also of the evdev and some others CLI Utilities.

Xinput Linux Tutorial - Featured

GNU/Linux Xinput QuickStart Guide