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

You can use mongo --eval 'printjson(db.getCollectionNames())' to get the list of collections and then do a mongoexport on all of them. Here is an example in ruby

  out = `mongo  #{DB_HOST}/#{DB_NAME} --eval "printjson(db.getCollectionNames())"`

  collections = out.scan(/\".+\"/).map { |s| s.gsub('"', '') }

  collections.each do |collection|
    system "mongoexport --db #{DB_NAME}  --collection #{collection}  --host '#{DB_HOST}' --out #{collection}_dump"
  end