How to free-up space allocated to text/image fields in Sybase ASE

This how-to explains how to reclaim space from a Sybase ASE text field.

First of all, if you want your text/image fields to use the least possible space, you must define them to allow nulls on table creation, or when altering the table.

You can easily monitor the space used by text and image fields using sp_spaceused:
sp_spaceused objname, 1