public function validateCommand ($attribute)
		{
			if (!$this->hasErrors())
			{
				$return_var1 = $return_var2 = $return_var3 = 0;
				exec('command -v ' . $this->$attribute . '', $output, $return_var);
				if ($return_var == 127)
					$this->addError($attribute, Yii::tr('Command not found.', [], 'setting'));
			}
		}