Fix description of GLOG_log_dir

tutorials/source_en/advanced_use/customized_debugging_information.md

@@ -222,4 +222,4 @@ MindSpore uses glog to output logs. The following environment variables are comm
 
 1. GLOG_v specifies the log level. The default value is 2, indicating the WARNING level. The values are as follows: 0: DEBUG; 1: INFO; 2: WARNING; 3: ERROR.
 2. When GLOG_logtostderr is set to 1, logs are output to the screen. If the value is set to 0, logs are output to a file. Default value: 1
-3. GLOG_log_dir=YourPath specifies the log output path. If GLOG_log_dir is specified and the value of GLOG_logtostderr is 1, logs are output to the screen but not to a file.
+3. GLOG_log_dir=YourPath specifies the log output path. If GLOG_logtostderr is set to 0, value of this variable must be specified. If GLOG_log_dir is specified and the value of GLOG_logtostderr is 1, logs are output to the screen but not to a file. Logs of C++ and Python will be output to different files.

tutorials/source_zh_cn/advanced_use/customized_debugging_information.md

@@ -221,4 +221,4 @@ MindSpore采用glog来输出日志，常用的几个环境变量如下：
 
 1. GLOG_v 控制日志的级别，默认值为2，即WARNING级别，对应关系如下：0-DEBUG、1-INFO、2-WARNING、3-ERROR。
 2. GLOG_logtostderr 值设置为1时，日志输出到屏幕；值设置为0时，日志输出到文件。默认值为1。
-3. GLOG_log_dir=YourPath 指定日志输出的路径。若指定了GLOG_log_dir且GLOG_logtostderr的值为1时，则日志输出到屏幕，不输出到文件。
+3. GLOG_log_dir=YourPath 指定日志输出的路径。若GLOG_logtostderr的值为0，则必须设置此变量。若指定了GLOG_log_dir且GLOG_logtostderr的值为1时，则日志输出到屏幕，不输出到文件。C++和Python的日志会被输出到不同的文件中。