Problem scenario description

我按照mongodb官网的 ubantu apt源安装完之后，命令行键入mongod -version是正常的：

我单独建立存储我项目的数据文件夹,其结构为:
                    -pile_db
                      -data
                      -log
                       -mongo.log
我在命令行键入 mongod --dbpath ~/pile_db/data --logpath ~/pile_db/log/mongo.log -logappend --fork
指定了data目录，log日志位置。此时系统中的mongod服务是已经开启的。

At this time, a system error occurred:

I checked the records in the log/mongo.log file:

said it was occupied by 0.0.0.0:27017, but I did not set up other mongo libraries. .
mongo did not connect to the data I set myself

Instead, this time the command line enters mongo

but this entry is not the data of the pile_db I pointed to.

I don’t understand how to change it. Please give me some advice. I’ve just come into contact with mongo. I see other tutorials and the connection goes smoothly, so I’m a little embarrassed.