In reply to Jerry Voight.

Hi Jerry, based on your input I revised my original code

data _null_;
infile inf;
input REC_TYPE $10. @;
input;
select(REC_TYPE);
. . .

to eliminate the trailing @ and consequently the second input statement:

data _null_;
infile inf;
input REC_TYPE $10.;
select(REC_TYPE);
. . .

and provided corresponding explanation.

Thank you again for your INPUT (pun is coincidentally intended :) .)