How to Update Magento 2.1x to latest version via SSH

composer require magento/product-community-edition 2.1.9 --no-update
composer update
rm -rf var/di/* var/generation/* var/cache/* var/log/* var/page_cache/*
php bin/magento cache:clean
php bin/magento cache:flush
php bin/magento setup:upgrade
php bin/magento setup:di:compile
php bin/magento setup:static-content:deploy
php bin/magento indexer:reindex

Magento 2.1x Cron Jobs

Cron Jobs
Add through cPanel/WHM

Time interval – 10 minutes -> */10 * * * *

Replace ^username^ with user dir

php /home/^username^/public_html/bin/magento cron:run >/dev/null 2>&1
php /home/^username^/public_html/update/cron.php >/dev/null 2>&1
php /home/^username^/public_html/bin/magento setup:cron:run >/dev/null 2>&1

Using Crontab editor in Terminal

Use command crontab -e

*/10 * * * * php /home/^USERNAME AND PATH^/public_html/bin/magento cron:run >/dev/null 2>&1
*/15 * * * * php /home/^USERNAME AND PATH^/public_html/bin/magento indexer:reindex >/dev/null 2>&1

Start a magento instance programmatically

This Code:

$mageFilename = 'app/Mage.php';
require_once $mageFilename;
Mage::setIsDeveloperMode(true);
ini_set('display_errors', 1);
error_reporting(E_ALL & ~E_NOTICE);
umask(0);
Mage::app('admin');
Mage::register('isSecureArea', 1);
Mage::app()->setCurrentStore(Mage_Core_Model_App::ADMIN_STORE_ID);
//your mage code here