The %REPRO extension can be specified on the PARM keyword of the EXEC statement invoking IDCAMS, and on the PARM command. The syntax is:
%REPRO(VSAM | VSAMLAX | OSCOPY | OSCOPYLAX)
| Attribute | Must match for | 
|---|---|
| RECFM | OSCOPY and OSCOPYLAX | 
| DSORG | OSCOPY and OSCOPYLAX | 
| VSAM-KEY-OFFSET | OSCOPY and OSCOPYLAX | 
| VSAM-KEY-LENGTH | OSCOPY and OSCOPYLAX | 
| LRECL | OSCOPY and OSCOPYLAX | 
| LRECL-MAX (system managed) | OSCOPY and OSCOPYLAX | 
| LRECL-MIN (system managed) | OSCOPY and OSCOPYLAX | 
| CHARSET (EBCDIC or ASCII) | OSCOPY | 
| EXTENDED-TYPE (system managed. Indicates base cluster, aix, etc.) | OSCOPY | 
| REUSE/NOREUSE | OSCOPY | 
| UNIQUEKEY/NONUNIQUEKEY (for AIXs and PATHs) | OSCOPY | 
For example:
//STEPAMS  EXEC PGM=IDCAMS,PARM=';MFE:%REPRO(OSCOPY)'
//SYSPRINT  DD SYSOUT=*
//VSAMDATA  DD *
AA
BBB
//SYSIN  DD *
  PARM ;MFE: %REPRO(VSAM)
  /* Next REPRO will use normal REPRO */ 
  REPRO  IFILE (VSAMDATA)                          -
         ODS   (MFIDSA.REPROOS.KSDS1)
  PARM ;MFE: %REPRO(OSCOPY)
  /* All REPRO(s), until another PARM command specifies –
     otherwise, will use OS copy if possible */
  REPRO  IDS   (MFIDSA.REPROOS.KSDS1)              -
         ODS   (MFIDSA.REPROOS.KSDS2)
            	 The extension comes after a semicolon, so that the mainframe will see it as a comment. However, if the extension is the only option to the PARM command, the mainframe reports an error. To prevent this, you must code at least one option in addition to the extension. For example, rather than coding exactly as in the example above, you could code:
PARM='MAR(2,72);MFE: %REPRO(OSCOPY)'
or equivalently:
PARM MAR(2,72);MFE: %REPRO(OSCOPY)