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Gentoo one liners¶
On our Linux list at work the topic of Gentoo usage arose again today. Originally, the topic was about interesting one liners used to maintain a Gentoo system. I found myself posting extended replies to some of the questions and I’m reposting a few of those here.
How do I get just the list of packages that are installed but not in
world?
The constraint here is packages that were installed with --oneshot,
or manually removed from /var/lib/portage/world, which means that they
will no longer be updated automatically. I often use this for packages I’m
just playing with, and it appears lots of others do the same. While the output
of emerge --pretend --depclean is all that is really needed, the question
is how to get a list of just the packages.
$ emerge --pretend --depclean
<snipped heaps of output>
gnome-base/orbit
selected: 2.14.17
protected: none
omitted: none
app-text/iso-codes
selected: 3.8
protected: none
omitted: none
dev-libs/dbus-glib
selected: 0.76
protected: none
omitted: none
sys-apps/dbus
selected: 1.2.3-r1
protected: none
omitted: none
>>> 'Selected' packages are slated for removal.
>>> 'Protected' and 'omitted' packages will not be removed.
Packages installed: 477
Packages in world: 86
Packages in system: 50
Required packages: 348
Number to remove: 129
The output we want can be easily matched with RegEx, and the bash alias below will list just the packages by piping the output through sed. We can even use the one liner as input to a larger function if we only want to see top-level packages; that is packages that aren’t listed as dependencies of other packages:
alias pkgclean="emerge ----pretend --depclean | sed -n '/^ [a-z]/s,^ ,,p' | sort"
toppkgclean() {
local depfiles=$(find /var/db/pkg/ -name RDEPEND -o -name PDEPEND)
local cleanlist=$(pkgclean)
for package in ${cleanlist}
do
LC_ALL=C grep -q ${package} ${depfiles} || echo ${package}
done
}
Is it possible to use :command:`bash` completion to complete package names
for use in :file:`package.keywords`?
I actually wrote the following little function in reply to a user asking
a similar question in #gentoo on Freenode a couple of months ago:
arch_unmask() {
local s done
if [[ -z $1 ]]
then
echo "${FUNCNAME} <category/package> [arch]"
return 1
fi
for s in $(portageq envvar PORTDIR PORTDIR_OVERLAY)
do
if [[ -d $s/$1 ]]
then
echo $1 $2 >>/etc/portage/package.keywords/testing
done=1
break
fi
done
if [[ -z "${done}" ]]
then
echo "Doesn't exist ‘$1’"
return 1
fi
}
complete -F _emerge arch_unmask
Note
If you’re using our Gentoo boxes at the office the function will be much
faster if you replace the call to portageq by
/var/lib/repos/*, as our package trees are always installed there. The
portageq call is mainly there for users who use /usr/portage
and /usr/local/portage, or other such monstrosities.
The final question I looked at was:
Is there an easy way to clean all the old modules from
/lib/modules?
Assuming you are trying to remove all modules that don’t belong to the current
kernel this is very easy using bash’s extglob support. It may
need to be enabled in your session, you can test whether it is enabled with
shopt extglob.
$ echo /lib/modules/*
/lib/modules/2.6.31.1 /lib/modules/2.6.31.2-jr2 /lib/modules/2.6.31.3-mk1
$ echo /lib/modules/!($(uname -r))
/lib/modules/2.6.31.1 /lib/modules/2.6.31.2-jr2
The !($(uname -r)) syntax tells bash to match all but 2.6.31.3-mk1 (the
output of uname -r on my system), there are plenty of other uses for
extglob and the documentation has examples.
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