SYMNAMES is a means of defining variables in SORT. When you have a complex sortcard, it becomes hard to have your sort control card ‘readable / understandable’. It is a good practice to always use SYSNAMES DD to define variables and then use the logical variable names in Sort card.
Below is an example with the SYMNAMES DD (variables declared) and SYSIN (the ‘sort control card’).
//SORTSTEP EXEC PGM=SORT //SYSOUT DD SYSOUT=* //SORTIN DD DISP=SHR, // DSN=MYDSN.NAME //SORTWK01 DD UNIT=SYSDA,SPACE=(CYL,2000) //SORTWK02 DD UNIT=SYSDA,SPACE=(CYL,2000) //SORTWK03 DD UNIT=SYSDA,SPACE=(CYL,2000) //SYMNAMES DD * Name,1,10,CH Age,11,2,ZD /* //SYSIN DD * SORT FIELDS=(Age,D) INCLUDE FILEDS=(Age,GT,25) /* //SORTOUT DD DISP=(NEW,CATLG,DELETE), // SPACE=(CYL,(250,100),RLSE), // UNIT=DISK, // DCB=(RECFM=FB,LRECL=80,BLKSIZE=0), // DSN=MYDSN.OUTPUT.NAME
read more on SYMNAMES
Use this code 