The length of the control field image is completely determined by the length and format code of the control field. To shorten a control field image, specify the full length of the original control field as the l (length) value in the SORT/MERGE control statement. Then shorten each image by the same number of bytes and pad it uniformly to the length of the original field. Be sure to pad each control field image with the same leading or trailing character, and replace data in the control field image with the same type of data as that in the actual control field.