#!/usr/bin/env bash

# A script to perform incremental backups with rsync

DATETIME="$(date '+%Y-%m-%d_%H:%M:%S')"
readonly BACKUP_DIR="/mnt/backup"
readonly BACKUP_PATH="${BACKUP_DIR}/${DATETIME}"
readonly LATEST_LINK="${BACKUP_DIR}/latest"

TEMP_DIR=$(mktemp -d || echo "Failed to make temp dir"; exit 1)
chmod 700 "${TEMP_DIR}"
trap 'rm -rf "${TEMP_DIR}"; exit 0' EXIT SIGHUP SIGINT SIGQUIT SIGTERM

while read -r line; do
    rsync -aAX "$line" "${TEMP_DIR}";
done </etc/rsync-includes.txt

rsync -av --delete "${TEMP_DIR}/" --link-dest="${LATEST_LINK}" "${BACKUP_PATH}"

rm -f "${LATEST_LINK}"
ln -sf "${BACKUP_PATH}" "${LATEST_LINK}"