title: Multiple databases and collections mongodump
body: <p>I have something like this:</p>
  
  <pre><code>dbs=$(mongo --quiet --eval "db.getMongo().getDBNames()" --host exemple.com | \ 
              grep '"' | tr -d '"' | tr -d ',')
  
  for db in $dbs; do
      cols=$(mongo --quiet --eval "print(db.getCollectionNames())" $db \
                    --host exemple.com | tr ',' ' ')
      for col in $cols; do
          mongodump --host example.com -q "{_id:{\$gt:$oid}}" \
                     -d $dbs -c $col --out /data/
     done
  done
  </code></pre>
  
  <p>I'm getting: </p>
  
  <blockquote>
    <p>positional arguments not allowed</p>
  </blockquote>
  
  <p>How can I use <code>mongodump</code> for all collections in all databases ? </p>