Dshrink

Dshrink is a command line utility to compress the SIDEDEFS lump in WAD files. It was written in 1994 by Rand Phares and ran in DOS. The binaries were never officially released in a standalone ZIP format file. The executable was packaged alongside Doom episode replacement Cleimos created by Rand and Steven Phares. In 1998, Eric James Roberts (Ricrob) made available for download on his Doomworld-hosted web page. It was also published on Doomworld's "Editors & Utilities" section.

Dshrink will remove redundant sidedefs from levels by making many linedefs share one sidedef when all properties are the same. This sidedef compression will shrink the WAD file size. It will also permit larger levels to fit within sidedef limits of the original engine.

A WAD file output by Dshrink can be read and displayed by level editors but it can no longer be modified by most applications. Updating a level with compressed sidedefs will result in corrupt linedefs. Dshrink is unable to uncompress sidedefs to output a WAD file that be edited. However Doom Builder 2 and its forks will automatically uncompress sidedefs when a map is opened.

In 1998, Jim Flynn created counterpart tool Ushrink that will uncompress sidedefs and allow the level to again be edited.

In April 2020, Derek MacDonald (Afterglow) recovered the original source code from Rand and archived it on a GitHub-hosted repository.