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watersb
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Joined: 04 Sep 2002
Posts: 297
Location: where the hell is Tesuque, New Mexico?

PostPosted: Fri Apr 11, 2003 7:00 am    Post subject: Portage Dependency Tracing Reply with quote

You have just typed emerge -pu --deep world and all this stuff appears -- wow! You might ask:

What are all those pacakages for? Try emerge search <pkgname>

Why does it want to install a particular package? That is, where is a particular pacakge's dependency coming from?

This tip suggests a technique for dealing with the second question - where is the dependency for a package coming from?

For a third question -- Geez, do I have to install all this right now? -- you can find out how to defer unwanted packages during an "emerge -pu world", with this excellent tip.

I use the qpkg tool that is part of gentoolkit. But qpkg does not always help me...

You can dump a list of all currently-installed packages in a number of ways; one is to perform "emerge -pe world". The one that I use is to dump all entries in /var/db/pkg to a text file, like this:

Code:

# cd /var/dg/pkg
# find . -type d -mindepth 2 | sort > /tmp/packages-installed


Tonight I've been using this in conjunction with a little script that searches the package deps for entries:
Code:

#! /bin/bash

cd /var/cache/edb/dep
find . -type f | xargs grep -l $1 | sort > /tmp/pkgs-depending-on-$1


This gives a listing of all the dependencies for every package that is currently in portage, I think; anyway there are way more things in there than I have installed. And note that this will grab anything that matches lexically; that is, by package name.

Save this script in a file called "pkgdep", and then call it like:

Code:

$ pkg-dep pilot-link
$ cat /tmp/pkfs-depending-on-pilot-link


To answer a question like, "Why is package X getting added?", I've been doing cross-comparisons, searching through all the deps for package X against all of my currently-installed packages:

Code:

for pkg in `cat /tmp/packages-installed`
do
 grep $pkg /tmp/pkgs-depending-on-pilot-link
done


Using this technique is geared towards giving you false-positives; matches occur lexically, and may not be meaningul. I do this because I find that qpkg does not always give me results that I need; I'll read up on qpkg more...

Anyway, I have found this technique useful for sussing out package dependencies, and maybe it will help.
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mattsteven
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Joined: 27 Oct 2003
Posts: 240
Location: Your Planet

PostPosted: Sun Jul 04, 2004 4:54 pm    Post subject: Nicely done, this is very useful when bundled into a sin Reply with quote

this is very useful for solving the "why are all these unneccesary packages being installed" problem when bundled into a single script!

Code:

#!/bin/bash

if [ ! $1 ] ; then
        echo "Usage:  $0 packagename"
        exit 1
fi

if [ ! -f /tmp/packages-installed ] ; then
        cd /var/db/pkg
        find . -type d -mindepth 2 | sort > /tmp/packages-installed
fi

cd /var/cache/edb/dep/
find . -type f | xargs grep -l $1 | sort > /tmp/pkgs-depending-on-$1

for pkg in `cat /tmp/packages-installed`
do
        grep $pkg /tmp/pkgs-depending-on-$1
done


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Linux-only desktop since 1998
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