USE flag

USE flags are keywords that embodies support and dependency-information for a certain concept. They are a core feature of Gentoo, and a good understanding of how to deal with them is needed for administering a Gentoo system.

Basic concepts on how to implement USE flags can be found in the Handbook.

Declaring USE flags
The default set of USE flags is defined by the selected profile. Changing them can be done in and/or. For details see the Using USE flags section of the Handbook.

USEful commands
To check if a certain USE flag is activated and which packages use it, run:

Replace  with the USE flag to be checked.

Emerge command options
The command has some USE flag related options like:


 * emerge --changed-use (-U)
 * emerge --complete-graph-if-new-use < y | n >
 * emerge --newuse (-N)

For details see

Tools
Some tools are available for analyzing and managing USE flags:


 * euse
 * quse - for details see
 * equery hasuse (USE flag)
 * equery uses (package name)
 * ufed
 * - GTK Utility to help manage Portage's user config files
 * eix eix --use (USE flag), eix --installed-with-use (USE flag), eix --installed-without-use (USE flag)
 * - GTK Utility to help manage Portage's user config files
 * eix eix --use (USE flag), eix --installed-with-use (USE flag), eix --installed-without-use (USE flag)

External resources

 * https://packages.gentoo.org/useflags/ - USE flags on Gentoo Packages Database.
 * - The USE flag list can be seen locally on systems with Portage installed.
 * https://www.gentoo.org/support/use-flags/ - The full USE flag index.
 * https://devmanual.gentoo.org/general-concepts/use-flags/ - USE flags conceptually explained in the Gentoo Developer Handbook.