Equery

equery is a tool to make several common portage operations simpler. Among other operations, it can display package dependencies, metadata, and installed files.

Installation
Install :

Capabilities
To see a list of all equery's capabilities, simply run it without arguments:

Module (b)elongs
List what package  belongs to:

Module (d)epends
List all packages directly depending on udev:

Module (f)iles
List all files installed by ncmpcpp:

Descriptions of other modules and additional command line flags can be found in the equery man page.

Aliases
A common approach to working with equery is to create aliases. When using bash these can usually be placed in the file: