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Gentoo one-liners for a rainy day

Published: June 4th, 2025

Updated: July 3rd, 2025

Table of contents

Prerequisites

Install the necessary Portage utilities and GNU Parallel:

emerge -av app-portage/portage-utils app-portage/gentoolkit sys-process/parallel

Finding packages with the most dependencies

Show which packages pull in the greatest number of dependencies:

qlist -CI | sort -u | parallel 'echo $(qdepends -CqqQ {} | wc -l) {}' | sort -n > pkgs_with_most_deps.txt

What each part does:

  • qlist -CI: lists all installed packages without color output in category/package format.
  • sort -u: sorts output and removes duplicate entries.
  • parallel: executes dependency counting through GNU Parallel for better performance.
  • qdepends -CqqQ {}: queries dependencies without color output, quietly.
  • wc -l: counts the dependency lines.
  • sort -n: sorts numerically by dependency count.

The output shows dependency count followed by package name, from packages with the least dependencies to greatest.

Finding the largest packages

Find which packages consume the most storage:

qlist -CI | sort -u | parallel qsize -C | awk '{print $NF,$1}' | cut -d ':' -f 1 | sort -h > biggest_pkgs.txt

Breaking this down:

  • qsize -C: reports package sizes in human-readable format without color output.
  • awk '{print $NF,$1}': reorders output to put size first, then package name.
  • cut -d ':' -f 1: removes trailing colon.
  • sort -h: sorts by human-readable numbers (handles K, M, G suffixes).

This arranges packages from smallest to largest.

Combining package size and dependency count

Merge dependency and size data in one file for analysis:

join -j 2 -o 1.1,2.1,0 <(sort -k2 pkgs_with_most_deps.txt) <(sort -k2 biggest_pkgs.txt) | sort -n | tr ' ' '\t' > combined.txt

The join command joins lines of two files on a common field:

  • -j 2: join on field 2 (package names).
  • -o 1.1,2.1,0: output format (dependencies, size, package name).
  • <(sort -k2 ...): process substitution with secondary key sorting.
  • tr ' ' '\t': converts spaces to tabs for cleaner formatting.

Print packages without a package.env entry

Print packages not yet customized in /etc/portage/package.env:

comm -13 <(awk 'match($1, /^[a-zA-Z0-9_+-]+\/[a-zA-Z0-9_+-]+$/) {print $1}' /etc/portage/package.env/* | sort -u) <(qlist -CI | sort -u)

This comm usage compares sorted lists:

  • -13: shows only lines unique to installation.
  • awk 'match($1, /^[a-zA-Z0-9_+-]+\/[a-zA-Z0-9_+-]+$/)': extracts package in category/package format.

As above, but only larger packages

Focus on packages large enough to warrant optimization attention:

comm -13 <(awk 'match($1, /^[a-zA-Z0-9_+-]+\/[a-zA-Z0-9_+-]+$/) {print $1}' /etc/portage/package.env/* | sort -u) <(qlist -CI | sort -u) | grep -f - combined.txt | awk 'match($2, /^([0-9]{4}\.[0-9]K)|([0-9]+\.[0-9][MG])$/)' | sort -n

This adds size filtering:

  • grep -f -: uses the uncustomized package list as search patterns.
  • awk 'match($2, /^([0-9]{4}\.[0-9]K)|([0-9]+\.[0-9][MG])$/)': matches packages >=1000K.

Analyzing upgradeable packages

Find packages not yet customized in /etc/portage/package.env that already need an upgrade:

comm -13 <(awk 'match($1, /^[a-zA-Z0-9_+-]+\/[a-zA-Z0-9_+-]+$/) {print $1}' /etc/portage/package.env/* | sort -u) <(EIX_LIMIT=0 eix -u -# | sort -u)
  • EIX_LIMIT=0: removes eix output limits.
  • eix -u -#: lists upgradeable packages in category/package format.

Multi-column sorting

Use multiple sort keys for different analysis priorities:

sort -k1,1n -k2,2h combined.txt
sort -k2,2h -k1,1n combined.txt

The first command prioritizes dependency count, using size as a tiebreaker. The second makes size the primary criterion. The h and n refer to human-readable and numeric sorting.

Practical applications

These commands identify large packages that can be replaced with lightweight alternatives, which proves useful for several reasons:

  • Freeing up storage space.
  • Creating a more minimal system.

I used these commands to guide CFLAGS tweaking to better optimize Gentoo in a Virtual Machine (VM), since VMs have limited resources. I use a setup where video playback doesn't benefit from hardware acceleration at the time of writing (Qubes OS). I wanted to see if this approach could make a difference.

I think I managed to gain a few Frames Per Second (FPS) from this, but I didn't benchmark it beyond comparing frame timings in mpv. The gain was relatively minor (<=10fps).

These days I believe strongly in benchmarking and profiling, as they make a real difference. The gains from those techniques typically exceed the gains from CFLAGS tweaking.