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

If you are OK with the bson format, then you can use the mongodump utility with the same -d flag. It will dump all the collections to the dump directory (the default, can be changed via the -o option) in the bson format. You can then import these files using the mongorestore utility.