ArchLinux tips

A bunch of recipes useful for an ArchLinux system environment.

Mostly around system administration.

Custom Repos and Packages

In the repo directory, put all the packages in there.

repo-add ./custom.db.tar.gz ./*

Add to pacman.conf:

[custom]
SigLevel = [Package|Databse]Never|Optional|Required
Server = path-to-repo

See also repo-remove. A package database is a tar file, optionally compressed. Valid extensions are .db or .files followed by an archive extension of .tar, .tar.gz, .tar.bz2, .tar.xz, or .tar.Z. The file does not need to exist, but all parent directories must exist. ?Can we create a rpmgot.php hack?

Safe automatic pacman upgrades

• safepac : This is an approach for automating pacman upgrades yet catching problematic updates before hand.

Building packages

requires: @base-devel, abs, fakeroot

makepkg -s 

or

makeworld ?

Working with the serial console

Configure your Arch Linux machine so you can connect to it via the serial console port (com port). This will enable you to administer the machine even if it has no keyboard, mouse, monitor, or network attached to it (a headless server).

Configuration

Add this to the bootloader kernel line:

console=tty0 console=ttyS0,9600

From systemd:

systemctl enable [email protected] 

Installing Arch Linux using the serial console

1. Boot the target machine using the Arch Linux installation CD.
2. When the bootloader appears, select "Boot Arch Linux ()" and press tab to edit
3. Append console=ttyS0 and press enter
4. Systemd should now detect ttyS0 and spawn a serial getty on it, allowing you to proceed as usual

Note: After setup is complete, the console settings will not be saved on the target machine; in order to avoid having to connect a keyboard and monitor, configure console access on the target machine before rebooting.

Identifying files not owned by any package

pacman-disowned

#!/bin/sh

tmp=${TMPDIR-/tmp}/pacman-disowned-$UID-$$
db=$tmp/db
fs=$tmp/fs

mkdir "$tmp"
trap 'rm -rf "$tmp"' EXIT

pacman -Qlq | sort -u > "$db"

find /bin /etc /sbin /usr 
  ! -name lost+found 
  ( -type d -printf '%p/n' -o -print ) | sort > "$fs"

comm -23 "$fs" "$db"

Pacman one liners

• Remove packages and its dependancies. pacman -Rs ...

• List explicitly installed packages pacman -Qeq

• List orphans pacman -Qtdq

• Remove everything but base group pacman -Rs $(comm -23 <(pacman -Qeq|sort) <((for i in $(pacman -Qqg base); do pactree -ul $i; done)|sort -u|cut -d ' ' -f 1))

• Listing changed configuraiton files pacman -Qii | awk '/^MODIFIED/ {print $2}'

• Download a package without installing it pacman -Sw package_name

• Manage pacman cache

  paccache -h