To specify a particular record structure as the default if the .idy if it contains multiple record structures:
dfstrcl "C:\test layout\staff.idy" /d clerical_record /o "C:\test data\clerical_staff.str"
This specifies clerical_record as the default record layout where the information file contains multiple record layout structures. The /o parameter specifies a new location and filename for the record layout (.str) file.