How to export all collections in MongoDB?

Question

I want to export all collections in MongoDB by the command:

mongoexport -d dbname -o Mongo.json

The result is:
No collection specifie

Answer 1

I found after trying lots of convoluted examples that very simple approach worked for me.

I just wanted to take a dump of a db from local and import it on a remote instance:

on the local machine:

mongodump -d databasename

then I scp'd my dump to my server machine:

scp -r dump user@xx.xxx.xxx.xxx:~

then from the parent dir of the dump simply:

mongorestore 

and that imported the database.

assuming mongodb service is running of course.