This also recognizes single dashes as invalid input:
rsync_tmbackup.sh - 1 2 3
Expected output: an error because it's unknown what the single `-` could mean
Actual output:
rsync_tmbackup: Safety check failed - the destination does not appear to be a backup folder or drive (marker file not found).
rsync_tmbackup: If it is indeed a backup folder, you may add the marker file by running the following command:
rsync_tmbackup:
rsync_tmbackup: mkdir -p -- "1" ; touch "1/backup.marker"
rsync_tmbackup: