For example i have collection with name logs and db postfix, the output for dumped DB will be located to /tmp/backupmong
mongodump --out /tmp/backupmong/ --collection logs --db postfix
The command above will generating 2 files .bson and .metadata.json
Here’s the command for restoring the database (collection) by using .bson file.
mongorestore /tmp/backupmong/postfix/logs.bson -d anotherdb -c anotercol