Drush for non-composer drupal

 1#install composer and Drush
 2curl -sS https://getcomposer.org/installer | sudo php -- --install-dir=/usr/local/bin --filename=composer
 3wget -O drush.phar https://github.com/drush-ops/drush-launcher/releases/download/0.6.0/drush.phar
 4chmod +x drush.phar
 5sudo mv drush.phar /usr/local/bin/drush
 6cd drupal
 7cat > composer.json<<'EOF'
 8{
 9    "require": {
10        "drush/drush": "8.*"
11    },
12    "extra": {
13        "installer-paths": {
14            "core": ["type:drupal-core"]
15        }
16    }
17}
18EOF
19composer install