Backup from source to destination with retention and dry run.
Usage: ./BackupScript [options]
Backup from source to destinations with backup retention
-h --help Display help
-d --dry-run Perform a trial run with no changes
-e --exclude Exclude list file.
-r --retention <num> Set number of backup versions to retain
--src Set source directory
--dst Set destination directory
--use-defaults Run with default values