Gentoo Cheat Sheet

This is a reference card of useful commands for administrating Gentoo.

Portage tree sync methods
Sync the Portage tree using the mirrors by fetching the latest differences:

Sync the Portage tree using the mirrors by obtaining a Portage snapshot that is at most a day old:

Sync local overlays and the Portage tree using eix:

can be installed by issuing:

Gather more information on eix by reading its manual:

Package installation and removal
In the following tips will be used as an example, substitute the package of interest with FireFox to perform the actions on another package.

List what packages would be installed without installing them:

Install a specific version of a package:

Remove a package that no other packages depend on:

Remove a package even if it is needed by other packages:

Remove no longer needed packages:

As a safety measure, depclean will not remove any packages unless *all* required dependencies have been resolved. As a consequence of this, it often becomes necessary to run:

Avoid unnecessary rebuilds when USE flags only get added to or dropped from the repository.

Package upgrades
Upgrade all installed packages, dependencies, and deep dependencies that are outdated or have USE flag changes (avoiding unnecessary rebuilds when USE changes have no impact):

Package troubleshooting
Check for and rebuild missing libraries:

equery is part of. You can obtain it by issuing this command:

Tell which installed package provides a command using equery:

Tell which packages depend on a specific package (cat/pkg in the example) using equery:

Get information about a package using eix:

Portage enhancements
A graphical user interface to use with the Portage tree:

Manage configuration changes after an emerge completes:

After installations or updates
Rebuilds packages that depend on an recently updated library:

After updating perl-core packages:

After updating python core packages:

USE flags
Obtain descriptions and usage of the USE flag  using euse:

Gather more information on euse by reading its manual page:

Obtain a description of the  USE flag:

Show what packages have mysql use flag option:

Show what packages are currently built with mysql use flag:

Show what use flags are available for a specific package:

Quickly add a required USE flag for a package install:

Important Portage files

 * - Global settings (USE flags, compiler options).
 * - USE flags of individual packages.
 * - Keyword individual packages; e.g., , or.
 * - Accepted licenses
 * - List of explicitly installed package atoms.
 * - Contains for every installed package a set of files about the installation.

genlop
genlop is a Portage log processor, also estimating build times when emerging packages.

Install genlop by issuing:

You can gather more information on by reading its manual page:

View last 10 emerges (installs), run:

View how long emerging OpenOffice took, run:

Estimate how long emerge -uND --with-bdeps=y @world will take, run:

Have a console watching the latest merging ebuild during system upgrades, run:

Services
Obtain root shell (if the current user is listed in the sudoers list):

Start the ssh daemon in the default runlevel at boot:

Start the sshd service now:

Check if the sshd service is running:

Gentoo Monthly Newsletter (GMN)
Search packages in Portage by regular expressions:

Overlays vary from very small to very large in size. As a result they slow down the majority of Portage operations. That happens because overlays do not contain metadata caches. The cache is used to speed up searches and the building of dependency trees. A neat trick is to generate local metadata cache after syncing overlays.

This trick also works in conjunction with eix. eix-update can use metadata cache generated by emerge –-regen to speed up things. To enable this, add the following variable to :

qcheck
Use qcheck to verify installed packages:

qcheck</tt> comes with and can be installed by running this command:

Learn more about qcheck</tt> by reading its manual page:

External resources

 * Original gentoo-cheat repository.
 * Forum post about gentoo-cheat.
 * Collection of Gentoo tips.