我在 Apache2 上部署了 Ruby on Rails（如何：http://www.modrails.com/videos/passenger.mov）
在我重新启动 apache 之后，错误出现了
[Wed Oct 21 00:45:48.781816 2015] [core:warn] [pid 10994] AH00111: Config variable ${APACHE_LOCK_DIR} is not defined [Wed Oct 21 00:45:48.781905 2015] [core:warn] [pid 10994] AH00111: Config variable ${APACHE_PID_FILE} is not defined [Wed Oct 21 00:45:48.781931 2015] [core:warn] [pid 10994] AH00111: Config variable ${APACHE_RUN_USER} is not defined [Wed Oct 21 00:45:48.781945 2015] [core:warn] [pid 10994] AH00111: Config variable ${APACHE_RUN_GROUP} is not defined [Wed Oct 21 00:45:48.781967 2015] [core:warn] [pid 10994] AH00111: Config variable ${APACHE_LOG_DIR} is not defined [Wed Oct 21 00:45:48.785039 2015] [core:warn] [pid 10994:tid 3074509440] AH00111: Config variable ${APACHE_LOG_DIR} is not defined [Wed Oct 21 00:45:48.785239 2015] [core:warn] [pid 10994:tid 3074509440] AH00111: Config variable ${APACHE_LOG_DIR} is not defined [Wed Oct 21 00:45:48.785261 2015] [core:warn] [pid 10994:tid 3074509440] AH00111: Config variable ${APACHE_LOG_DIR} is not defined AH00526: Syntax error on line 74 of /etc/apache2/apache2.conf: Invalid Mutex directory in argument file:${APACHE_LOCK_DIR}
我看过这但没有用..（操作系统是 Xubuntu）