Sync directories and files between two servers

sync.sh

#!/bin/bash

# sync.sh
# Syncs directories and files between two servers

MAIN_SERVER_IP='12.34.56.78'
REMOTE_KEY='/home/ubuntu/key.pem'
REMOTE_USER='ubuntu'

# from:to pairs
BACKUP_DIRS=(
    "/home/ubuntu/downloads:/home/ubuntu/"
    "/home/ubuntu/uploads:/home/ubuntu/"
)

for entry in "${BACKUP_DIRS[@]}" ; do
    KEY="${entry%%:*}"
    VALUE="${entry##*:}"

    rsync -vrh $REMOTE_USER@$MAIN_SERVER_IP:$KEY $VALUE -e "ssh -i $REMOTE_KEY"
done