Gentoo Cheat Sheet

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

Portage package management

Portage tree sync methods

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

root #emerge --sync

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

root #emerge-webrsync

Sync local overlays and the Portage tree using eix:

root #eix-sync

app-portage/eix can be installed by issuing:

root #emerge -a eix

Gather more information on eix by reading its manual:

user $man eix

Package installation and removal

In the following tips www-client/firefox 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:

root #emerge -pv www-client/firefox

Install a specific version of a package:

root #emerge =www-client/firefox-24.8.0

Remove a package and the dependencies that no other packages depend on:

root #emerge -cav www-client/firefox

Remove a package but not its dependencies:

root #emerge -C www-client/firefox

Remove no longer needed packages:

root #emerge -av --depclean

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:

root #emerge --update --newuse --deep @world

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

root #emerge --update --changed-use --deep @world

Package upgrades

Upgrade all installed packages, dependencies, and deep dependencies that are outdated or have USE flag changes:

root #emerge -uDN --with-bdeps=y @world

Package troubleshooting

Check for and rebuild missing libraries:

root #revdep-rebuild -v

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

root #emerge -a gentoolkit

Tell which installed package provides a command using equery:

user $equery b `which vim`

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

user $equery d www-client/firefox

Get information about a package using eix:

root #eix www-client/firefox

Portage enhancements

A graphical user interface to use with the Portage tree:

root #porthole

Manage configuration changes after an emerge completes:

root #dispatch-conf

After installations or updates

Rebuilds packages that depend on an recently updated library:

root #revdep-rebuild

After updating perl-core packages:

root #perl-cleaner --all

After updating python core packages:

root #python-updater

USE flags

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

user $euse -i X

Gather more information on euse by reading its manual page:

user $man euse

Obtain a description of the png USE flag:

user $euse -i | grep png

Show what packages have mysql use flag option:

user $equery hasuse mysql

Show what packages are currently built with mysql use flag:

user $eix --installed-with-use mysql

Show what use flags are available for a specific package:

user $equery uses <package-name>

Quickly add a required USE flag for a package install:

root #echo 'dev-util/cmake -qt4' >> /etc/portage/package.use

Important Portage files[i 1]

Log management

genlop

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

Install genlop by issuing:

root #emerge -a app-portage/genlop

You can gather more information on app-portage/genlop by reading its manual page:

root #man genlop

View last 10 emerges (installs), run:

root #genlop -l | tail -n 10

View how long emerging OpenOffice took, run:

root #genlop -t openoffice

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

root #emerge -pU world | genlop --pretend

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

root #watch genlop -unc

Services

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

user $sudo -s

Start the ssh daemon in the default runlevel at boot:

root #rc-update add sshd default

Start the sshd service now:

root #rc-service sshd start

Check if the sshd service is running:

root #rc-status sshd

Gentoo Monthly Newsletter (GMN)

Search packages in Portage by regular expressions:

root #emerge -s "%^python$"

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.

root #emerge --regen

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 /etc/eixrc/00-eixrc:

FILE /etc/eixrc/00-eixrc
OVERLAY_CACHE_METHOD="assign"

qcheck

Use qcheck to verify installed packages:

root #qcheck -e vim-core

qcheck comes with app-portage/portage-utils and can be installed by running this command:

root #emerge -a app-portage/portage-utils

Learn more about qcheck by reading its manual page:

user $man qcheck

See also

External resources

References