Here is a simple RPG IV (ILE RPG) program that reads all records from file FILEA, checks field Field1 for lowercase letters, converts any lowercase text to uppercase, and updates the record if needed.
**FREE
ctl-opt dftactgrp(*no) actgrp(*caller);
// Declare the file
dcl-f FILEA usage(*update) keyed;
// Declare variables
dcl-s upperField varchar(256); // adjust length to match Field1
// Main logic
dow '1';
read FILEA;
if %eof;
leave;
endif;
// Convert Field1 to upper and compare
upperField = %xlate('abcdefghijklmnopqrstuvwxyz'
: 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
: Field1);
if upperField <> Field1;
Field1= upperField;
update FILEA;
endif;
enddo;
*inlr = *on;
return;