BPXWDYN is IBM supplied utility. The main use of it is we can dynamically allocate a file in the COBOL/PLi program.

Cobol Program:

01 WS-TEXT     PIC X(55) VALUE   "ALLOC FI(OUT) DS('WORK.TAPE') NEW KEEP UNIT(TAPE) REUSE"  

After this,

CALL BPXWDYN USING WS-TEXT.

After calling this program, the said file will be allocated.