+bf(--backup) but uses the same bf(--backup-dir) and bf(--suffix) settings,
+if any. With bf(--backup-dir), each backup file is placed inside the backup
+dir according to the source file's full path from the working directory
+bf(--backup) but uses the same bf(--backup-dir) and bf(--suffix) settings,
+if any. With bf(--backup-dir), each backup file is placed inside the backup
+dir according to the source file's full path from the working directory