./mongod

问题：ERROR: dbpath (/data/db/) does not exist.
 Create this directory or give existing directory in --dbpath.
解决：
./mongod --dbpath=/data/db
问题：ERROR: dbpath (/data/db) does not exist.
Create this directory or give existing directory in --dbpath.
解决：mkdir data
cd data
mkdir db
然后运行./mongod --dbpath=/data/db
最后在打开一个终端，运行./mongo