dh_compress - compress files and fix symlinks in package build directories
dh_compress [debhelper options] [-Xitem] [-A] [file ...]
dh_compress is a debhelper program that is responsible for compressing the files in package build directories, and makes sure that any symlinks that pointed to the files before they were compressed are updated to point to the new files.
By default, dh_compress compresses files that debian policy mandates should be compressed, namely all files in usr/share/info, usr/share/man, usr/X11R6/man, files in usr/share/doc that are larger than 4k in size, (except the copyright file, .html and .css files, and files that appear to be already compressed based on their extensions), and all changelog files. Plus PCF fonts underneath usr/X11R6/lib/X11/fonts/ and usr/share/fonts/X11/
If a debian/package.compress file exists, the default files are not compressed. Instead, the debian/packages.compress is ran as a shell script, and all filenames that the shell script outputs will be compressed. The shell script will be run from inside the package build directory. Note though that using -X is a much better idea in general; you should only use a debian/package.compress file if you really need to.
Debian policy, version 3.0
This program is a part of debhelper.
Joey Hess <email@example.com>