The CLP for DB2 will always return the maximum amount required for a field in its output based on the length of the column.
However, you can cast your field to another size VARCHAR:
SELECT CAST(your_field AS VARCHAR(100)) FROM your_table
If you do this, you'll probably want to suppress warnings for character truncation, which you can do using the CLP command UPDATE COMMAND OPTIONS
:
UPDATE COMMAND OPTIONS USING w OFF