The only way that comes to mind is to alloc the dataset via a CLIST or REXX, then use that dataset in a following step.
Here is a snippet from a CLIST that appends .Dyyyymm (where yyyymm is current year and month e.g. 200912 for Dec ’09) to a DSN.
SET LOGFIL=&STR(‘your dsn that will be suffixed with the date’)
SET CDATE = &SUBSTR(1:4,&SYS4SDATE)&SUBSTR(6:7,&SYS4SDATE)
SET LOGFIL = &LOGFIL..&STR(D)&CDATE&STR(‘)
ALLOC FI(LOG) DA(&LOGFIL) NEW +
LRECL(150) BLOCK(5000) +
SPACE(1,1) CYLINDERS RECFM(V,B) DSORG(PS) CATALOG
// EXEC PGM=IKJEFT0
run the CLIST from above
// EXEC this is your step using the DSN allocated
Now, having said that, I suggest you might consider GDGs. Who cares what the current date is?
Another approach, IF you have a JCL set up crew – might called production control or JCL staff or I/O control or whatever.
You can always use PROCs in your job streams and have the JCL staff modify a parm before each run of the job. This only works if you have a JCL staff that does job set up before execution. Some places do, and many do not.
IF you do have these folks, try something like this:
// PROC procname
// EXEC your job step
// DD DSN=some.name.D&date, …
// EXEC PROC=procname,date=200912
Where your JCL setup folks would actually change the value in the EXEC PROC= statement every time.
Almost forgot to mention the SET command for JCL
Again, this requires manual intervention each time it runs, so this is only valid if you have the afore mentioned JCL set up crew.
// SET PARM1=’xxx.yyy.DEC09′
// EXEC PGM=abcdef
//JCLIN DD DSN=&PARM1,DISP=NEW
//STEP02 EXEC PGM=defghi
//DDIN DD DSN=&PARM1,DISP=OLD