DialogWeb Help:  The IDO (Identify Duplicates Only) Command

The IDO command creates a set that contains only the records that are identified as duplicate records. It also sorts the records so that the duplicates are grouped together. IDO entered without a set number defaults to the last set created.

You can use IDO to check the results of the duplicate detection process to verify that unique records are not inadvertently removed by the REMOVE DUPLICATES command.

You can use IDO with the FROM option to identify duplicates from particular files, for example, ido s3 from 2,6,8.

Note:
If you use the IDO command with a search that includes one or more files that do not offer duplicate detection, a system message displays, the files that do offer duplicate detection will be processed. Records from unsupported files are not retained in the IDO set.