MongoDB: export and import a filtered set of documents

gistfile1.txt

#!/bin/bash

set -ex

now=$(date -u +%Y%m%d%H%M%S)
dest_dir="/tmp/"
dest_file="query_$now.json"

# Export your documents with a query
mongoexport --db YOURDB --username USERNAME --password PASSWORD --collection media \
            --query '{"media_for._ref.$id": { $in: [ ObjectId("4e9f46c96e48caa47f0006c7"), ... ] }}' \
            --jsonArray --out $dest_dir$dest_file

# If you want to just see the content in a nice format:
# cat $dest_dir$dest_file | python -mjson.tool

# DO SOME PROCESSING STUFF
magic_stuff_goes_here

# Import the previously exported documents
mongoexport --db YOURDB --username USERNAME --password PASSWORD --collection media \
            --jsonArray --file $dest_dir$dest_file