I've found this one out by accident. Debian packaging system has so many layers it can get confusing sometimes. Feta is a simple shell script that provides a common interface to all the layers.
They are often in a bit nicer format. Most commands seem to work the same way whether with .deb package file or with a package name.
Some common commands:
|Installing a package file||dpkg -i ~/foo.deb||feta install ~/foo.deb|
|Installing a package||apt-get install foo||feta install foo|
|Searching package descriptions||apt-cache search foo||feta search foo|
|Which package contains file||dpkg -S /bin/foo||feta find /bin/foo|
|List of files in a package||dpkg -L foo||feta contents foo|