Explanation:
The DELETE INPUT option of the BACKUP command enables you to delete the archive log files from the LOG_ARCHIVE_DEST_1 and leaves the files in the other log archive destinations. You can delete the archive log files from all enabled archiving destinations by performing a backup using the DELETE ALL INPUT option.
Reference:
Oracle 9i Net Services Administrator’s Guide
Oracle 9i Net Services Reference Guide
Oracle 9i Recovery Manager Reference
Oracle 9i Backup and Recovery Concepts

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