Mongo backup of whole database collections using mongoexport shell tool in json format

mongo-export.sh

#!/bin/bash

# tested on Mongo 3.6

DB='test'
USR='admin'
PSW='admin''
BACKUP_FOLDER="$DB-backup"

COLLECTIONS=$(mongo localhost:27017/$DB -u $USR -p $PSW --authenticationDatabase admin --quiet --eval "db.getCollectionNames()" | tr -d '\[\]\"[:space:]' | tr ',' ' ')

[-d $BACKUP_FOLDER ] || mkdir -p $BACKUP_FOLDER

for COLLECTION in $COLLECTIONS
do 
  echo "Exporting $DB/$COLLECTION..."
  mongoexport -u $USR -p $PSW --authenticationDatabase admin -d $DB -c $COLLECTION --out $BACKUP_FOLDER/$COLLECTION.json
done

echo "done."