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

How to Install CURL on Debian Gnu/Linux Distro

GNU/Linux Debian Installing cURL Guide

How to Install cURL on Debian GNU/Linux Distribution – Step by step Tutorial.

And cURL for Debian is a Computer Software Project providing a Library libcurl and Command-Line Tool curl for Transferring Data using various Network Protocols.

Step-by-step cURL Debian Installation Guide - Featured

GNU/Linux Debian Curl Installation Guide