PHP

wordpress debug log only

define( 'WP_DEBUG', true );
define( 'WP_DEBUG_LOG', true );
define( 'WP_DEBUG_DISPLAY', false );

wordpress throw to debug.log

 // Enable WP_DEBUG mode
define( 'WP_DEBUG', true );
// Enable Debug logging to the /wp-content/debug.log file
define( 'WP_DEBUG_LOG', true );
// Throw something:
error_log("My Error!");
// Tail -f /wp-content/debug.log (on linux, or your editor, or windows: BareTail)