Past

pacman and pkgfile

pacman the package management system


A simple library-based package manager.

 

In the October meeting, we discussed some of the most popular usages of
pacman and pkgfile, I intend to go into a bit more detail in this document.

 

Introduction

pacman is a utility which manages software packages in Linux. It uses simple compressed files as a package format, and maintains a text-based package database (more of a hierarchy), just in case some hand tweaking is necessary.

pacman does not strive to "do everything." It will add, remove and upgrade packages in the system, and it will allow you to query the package database for installed packages, files and owners. It also attempts to handle dependencies automatically and can download packages from a remote server.

History:

Version 2.0 of pacman introduced the ability to sync packages (the --sync option) with a master server through the use of package databases. Prior to this, packages would have to be installed manually using the --add and --upgrade operations.

Version 3.0 was the switch to a two-part pacman?—?a back-end named libalpm (library for Arch Linux Package Management) and the familiar pacman front-end. Speed in many cases was improved, along with dependency and conflict resolution being able to handle a much wider variety of cases. The switch to a library-based program should also make it easier in the future to develop alternative front ends.

Version 4.0 added package signing and verification capabilities to the entire makepkg/repo-add/pacman toolchain via GnuPG and GPGME.

Version 5.0 added support for pre/post-transaction hooks and sync database file list operations.

[From the manfile]:

pacman DESCRIPTION

Pacman is a package management utility that tracks installed packages

on a Linux system. It features dependency support, package groups,

install and uninstall scripts, and the ability to sync your local

machine with a remote repository to automatically upgrade packages.

Pacman packages are a zipped tar format.

 

Since version 3.0.0, pacman has been the front-end to libalpm(3), the

“Arch Linux Package Management” library. This library allows

alternative front-ends to be written (for instance, a GUI front-end).

 

Invoking pacman involves specifying an operation with any potential

options and targets to operate on. A target is usually a package name,

file name, URL, or a search string. Targets can be provided as command

line arguments. Additionally, if stdin is not from a terminal and a

single hyphen (-) is passed as an argument, targets will be read from

stdin.

 

The popular commands we discussed in the meeting:

for pacman

pacman -Syu #to update the entire system, (all packages)

Explainations:

-S, --sync

Synchronize packages. Packages are installed directly from the

remote repositories, including all dependencies required to run the

packages. For example, pacman -S qt will download and install qt

and all the packages it depends on. If a package name exists in

more than one repository, the repository can be explicitly

specified to clarify the package to install: pacman -S testing/qt.

You can also specify version requirements: pacman -S "bash>=3.2".

Quotes are needed, otherwise the shell interprets ">" as

redirection to a file.

 

In addition to packages, groups can be specified as well. For

example, if gnome is a defined package group, then pacman -S gnome

will provide a prompt allowing you to select which packages to

install from a numbered list. The package selection is specified

using a space- and/or comma-separated list of package numbers.

Sequential packages may be selected by specifying the first and

last package numbers separated by a hyphen (-). Excluding packages

is achieved by prefixing a number or range of numbers with a caret

(^).

 

Packages that provide other packages are also handled. For example,

pacman -S foo will first look for a foo package. If foo is not

found, packages that provide the same functionality as foo will be

searched for. If any package is found, it will be installed. A

selection prompt is provided if multiple packages providing foo are

found.

 

You can also use pacman -Su to upgrade all packages that are

out-of-date. See Sync Options below. When upgrading, pacman

performs version comparison to determine which packages need

upgrading. This behavior operates as follows:

 

Alphanumeric:

1.0a < 1.0b < 1.0beta < 1.0p < 1.0pre < 1.0rc < 1.0 < 1.0.a < 1.0.1

Numeric:

1 < 1.0 < 1.1 < 1.1.1 < 1.2 < 2.0 < 3.0.0

 

Additionally, version strings can have an epoch value defined that

will overrule any version comparison, unless the epoch values are

equal. This is specified in an epoch:version-rel format. For

example, 2:1.0-1 is always greater than 1:3.6-1.

 

-y, --refresh

Download a fresh copy of the master package database from the

server(s) defined in pacman.conf(5). This should typically be used

each time you use --sysupgrade or -u. Passing two --refresh or -y

flags will force a refresh of all package databases, even if they

appear to be up-to-date.

 

-u, --sysupgrade

Upgrades all packages that are out-of-date. Each

currently-installed package will be examined and upgraded if a

newer package exists. A report of all packages to upgrade will be

presented, and the operation will not proceed without user

confirmation. Dependencies are automatically resolved at this level

and will be installed/upgraded if necessary.

 

Pass this option twice to enable package downgrades; in this case,

pacman will select sync packages whose versions do not match with

the local versions. This can be useful when the user switches from

a testing repository to a stable one.

 

Additional targets can also be specified manually, so that -Su foo

will do a system upgrade and install/upgrade the "foo" package in

the same operation.

pacman -S # To install packages (listed packages or suites of packages)

(package names separated by spaces) … but you can also

use -Syu to install package(s) and upgrade everything as

well.

 

pacman -U # To install from file. (You can cd to directory with downloaded

and use this command to install the package)

 

-U, --upgrade

Upgrade or add package(s) to the system and install the required

dependencies from sync repositories. Either a URL or file path can

be specified. This is a “remove-then-add” process. See Upgrade

Options below; also see Handling Config Files for an explanation on

how pacman takes care of configuration files.

 

pacman -Ss # To search for a package

 

-s, --search <regexp>

Search each locally-installed package for names or descriptions

that match regexp. When including multiple search terms, only

packages with descriptions matching ALL of those terms are

returned.

 

pkfile DESCRIPTION

pkgfile searches the .files metadata created by repo-add(8) to retrieve

file information about packages. By default, the provided target is

considered to be a filename and pkgfile will return the package(s)

which contain this file. The repos which pkgfile searches is determined

by those enabled in /etc/pacman.conf.

 

The popular usages of pkgfile:

pkgfile <file-name-here> # Search for a command or package that may be part of a package a suite of packages, (such as ifconfig)

Examples:

$ pkgfile ifconfig

core/net-tools

$ pkgfile iwconfig

core/wireless_tools

$ pkgfile convert

extra/imagemagick

Of course, if the command is the same name of one single package, here is what you get:

$ pkgfile nmap

extra/nmap

There are several man pages available for the programs, utilities, and configuration files dealing with pacman.

Although the package manager itself is quite simple, many scripts have been developed that help automate building and installing packages. These are used extensively in Arch Linux. Most of these utilities are available in the Arch Linux projects code browser.

Other Utilities

Utilities available:

  • abs - ABS (Arch Build System), scripts to download & use the Arch Linux PKGBUILD tree

  • dbscripts - scripts used by Arch Linux to manage the main package repositories

  • devtools - tools to assist in packaging and dependency checking

  • namcap - a package analysis utility written in python

srcpac - a bash build-from-source pacman wrapper

 

=========================================

Here is a list of Linux Distributions that use pacman as their package
management system:

 

Antergos

Arch Linux

ArchBang

ArchLabs

ArchOne

BlackArch Linux

Chakra (operating system)

DeLi Linux

Frugalware Linux

Manjaro Linux

Parabola GNU/Linux-libre

Mailing Lists
There is a mailing list devoted to pacman development, hosted by Arch Linux. Subscribe or view the archives.

 

August 2017 Arch Linux Install

 

We got the install done, but there were two issues that did not get resolved.

1)  The xfce desktop menus were hidden and so were all icons.
Solution:  Install xf86-video-ati

2) BCM4321 wifi interface not workig.
Solution:  Install b43-firmware (From AUR)

After solving the above two issues, the laptop has a shiny new Arch Linux Operating System that seems to be fully functional.
(Using it now to write these notes).

So here are the install instructions from the official Arch Linux "Installation Guide", I'll try and designate or edit out the
steps that we can skip and add in a few notes that will help [any of us] with the next Arch Linux install. 
(From:  https://wiki.archlinux.org/index.php/installation_guide )
===================================================
Arch Linux should run on any x86_64-compatible machine with a minimum of 512 MB RAM. A basic installation with all packages from the base group should take less than 800 MB of disk space. As the installation process needs to retrieve packages from a remote repository, a working internet connection is required.

Download and boot the installation medium as explained in Category:Getting and installing Arch. You will be logged in on the first virtual console as the root user, and presented with a Zsh shell prompt; common commands such as systemctl(1) can be tab-completed.

To switch to a different console—for example, to view this guide with ELinks alongside the installation—use the Alt+arrow shortcut. To edit configuration files, nano, vi and vim are available.

Set the keyboard layout

(We skipped Setting the keyboard layout because it is US by default
so I deleted this section.)

Verify the boot mode   (We skipped the UEFI issue because the
laptop was pre-UEFI)

If UEFI mode is enabled on an UEFI motherboard, Archiso will boot Arch Linux accordingly via systemd-boot. To
verify this, list the efivars directory:

# ls /sys/firmware/efi/efivars

If the directory does not exist, the system may be booted in BIOS or CSM mode. Refer to your motherboard's
manual for details.

Connect to the Internet

The installation image enables the dhcpcd daemon on boot for wired network devices. The connection may be
checked with:

# ping archlinux.org

If no connection is available, stop the dhcpcd service with systemctl stop dhcpcd@, Tab and see Network configuration.

For wireless connections, iw(8), wpa_supplicant(8) and netctl are available. See Wireless network configuration.

Update the system clock

Use timedatectl(1) to ensure the system clock is accurate:

# timedatectl set-ntp true

To check the service status, use timedatectl status.

Partition the disks

When recognized by the live system, disks are assigned to a block device such as /dev/sda. To identify
these devices, use lsblk or fdisk — results ending in rom, loop or airoot may be ignored:

# fdisk -l

The following partitions (shown with a numerical suffix) are required for a chosen device:

Swap space can be set on a separate partition or a swap file.

To modify partition tables, use fdisk or parted. See Partitioning for more information.

If you want to create any stacked block devices for LVM, disk encryption or RAID, do it now.

(We used a test fdisk partition list to calculate how much to leave at the end for swap - we just set swap at the first of the drive ad the other partitio at the end and used the size of the last partition to recreate the first one - after deleting the partitions and starting over, we knew what size the / partition should be in order to leave 4G at the end.)

Format the partitions

Once the partitions have been created, each must be formatted with an appropriate file system. For
example, to format the root partition on /dev/sda1 with ext4, run:

# mkfs.ext4 /dev/sda1

See File systems#Create a file system for details.

Mount the file systems

Mount the file system on the root partition to /mnt, for example:

# mount /dev/sda1 /mnt

Create mount points for any remaining partitions and mount them accordingly, for example:

# mkdir /mnt/boot
# mount /dev/sda2 /mnt/boot

genfstab will later detect mounted file systems and swap space.

Installation

Select the mirrors

Packages to be installed must be downloaded from mirror servers, which are defined in
/etc/pacman.d/mirrorlist. On the live system, all mirrors are enabled, and sorted by their
synchronization status and speed at the time the installation image was created.

The higher a mirror is placed in the list, the more priority it is given when downloading a package.
You may want to edit the file accordingly, and move the geographically closest mirrors to the top
of the list, although other criteria should be taken into account.

This file will later be copied to the new system by pacstrap, so it is worth getting right.

Install the base packages

Use the pacstrap script to install the base package group:

# pacstrap /mnt base

This group does not include all tools from the live installation, such as btrfs-progs or specific
wireless firmware; see packages.both for comparison.

To install packages and other groups such as base-devel, append the names to pacstrap
(space separated) or to individual pacman commands after the #Chroot step.

Ok, instead of just the above command, we did a lot more:
# pacstrap /mnt base grub  networkmanager network-manager-applet xorg xfce4 xfce4-goodies 
alsa-utils udisks2 firefox sddm

Configure the system

Fstab

Generate an fstab file (use -U or -L to define by UUID or labels, respectively):

# genfstab -U /mnt >> /mnt/etc/fstab

Check the resulting file in /mnt/etc/fstab afterwards, and edit it in case of errors.

Chroot

Change root into the new system:

# arch-chroot /mnt

Time zone

Set the time zone:

# ln -sf /usr/share/zoneinfo/Region/City /etc/localtime

Run hwclock(8) to generate /etc/adjtime:

# hwclock --systohc
We could not get hwclock do do anythig so we just skipped it - all is well... 

This command assumes the hardware clock is set to UTC. See Time#Time standard for details.

Locale

Uncomment en_US.UTF-8 UTF-8 and other needed localizations in /etc/locale.gen, and
generate them with:

# locale-gen

Set the LANG variable in locale.conf(5) accordingly, for example:

/etc/locale.conf
LANG=en_US.UTF-8
We did:
echo LANG=en_US.UTF-8 > /etc/locale.cof

If you set the keyboard layout, make the changes persistent in vconsole.conf(5):

/etc/vconsole.conf
KEYMAP=de-latin1

Hostname

Create the hostname(5) file:

/etc/hostname
We did:
echo HP-6715b > /etc/hostame
myhostname

Consider adding a matching entry to hosts(5):

/etc/hosts
127.0.0.1       localhost.localdomain   localhost
::1             localhost.localdomain   localhost
127.0.1.1       myhostname.localdomain  myhostname

See also Network configuration#Set the hostname.

Network configuration

The newly installed environment has no network connection activated by default. See
Network configuration#Network managers
.

For Wireless configuration, install the iw and wpa_supplicant packages, as well as
needed firmware packages. Optionally install dialog for usage of wifi-menu.

Initramfs

Creating a new initramfs is usually not required, because mkinitcpio was run on installation of the
linux package with pacstrap.

For special configurations, modify the mkinitcpio.conf(5) file and recreate the initramfs image:

# mkinitcpio -p linux
We skipped this mkinitcpio step

Root password

Set the root password:

# passwd

Boot loader

See Category:Boot loaders for available choices and configurations.

We istalled grub as our boot loader so we did this:

# grub-install /dev/sda
# grub-mkconfig -o /boot/grub/grub.cfg

If you have an Intel CPU, install the intel-ucode package in addition, and enable microcode updates.

So before rebooting, we went a step further and created the user and added him to a
bunch of groups and set password for user:

# useradd -m -G wheel,video,audio,scanner,network,optical joe 
# passwd joe  
   type password 
   again…
So we went another step further and enabled the NetworkManager and the login manager
# systemctl enable NetworkManager
# systemctl enable sddm

Reboot

Exit the chroot environment by typing exit or pressing Ctrl+D.

Optionally manually unmount all the partitions with umount -R /mnt: this allows noticing any
"busy" partitions, and finding the cause with fuser(1).

Finally, restart the machine by typing reboot: any partitions still mounted will be automatically
unmounted by systemd. Remember to remove the installation media and then login into the
new system with the root account.

We did not login to the root account because we had already created the user and
had the login manager enabled.
Basically, we had already accomplished the post-install tasks and so we were pretty
much finished when it came time to reboot.
….Accept for the fact that we needed the ATI video driver and firmware for the BCM4321
wifi interface.

This probably should be in a separate article but...

.... Dennis had a problem with removable media in xfce.  The normal behavior is for an icon
to pop up on the desktop which was not happening for him.  There are also optoins in xfce

settings to auto mount and display contents of the removable drive in a file manager widow

that will automatically pop up on the screen.  That didn't happen for him either.

..... I've seen this before and the work-around I use is to install spacefm.  spacefm is a AUR
package.
Here are instructions for installing AUR packages.

 

ICS Internet Connection Sharing

We used IP tables rules and Network Address Translation to share the connection (NAT).  We also started a DHCP server and a Nameserver.  Here are the config files:

The DHCP server: /etc/dhcpd.conf
=============================
option domain-name-servers 192.168.123.1;
option subnet-mask 255.255.255.0;
option routers 192.168.123.1;
subnet 192.168.123.0 netmask 255.255.255.0 {
range 192.168.123.150 192.168.123.250;
}
==============================

The nameserver:   /etc/dnsmasq.conf
========================
interface=enp32s0
========================
(Yea, that's it, just one line...)

Here are the iptables rules that actually do the IP forwarding:
=============================
iptables -t nat -A POSTROUTING -o wlp8s0b1 -j MASQUERADE
iptables -A FORWARD -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
iptables -A FORWARD -i enp32s0 -o wlp8s0b1 -j ACCEPT
===========================

Here is ics.sh (the commands that will turn on ICS and start nameserver and DHCP servers:
===============================
ip addr add 192.168.123.1/24 dev enp32s0
sysctl net.ipv4.ip_forward=1
iptables -t nat -A POSTROUTING -o wlp8s0b1 -j MASQUERADE
iptables -A FORWARD -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
iptables -A FORWARD -i enp32s0 -o wlp8s0b1 -j ACCEPT
systemctl start dhcpd4
systemctl start dnsmasq
=================================

Here is kill-ics.sh
================================
sysctl net.ipv4.ip_forward=0
systemctl stop dnsmasq
systemctl stop dhcpd4
iptables -t nat -D POSTROUTING -o wlp8s0b1 -j MASQUERADE
iptables -D FORWARD -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
iptables -D FORWARD -i enp32s0 -o wlp8s0b1 -j ACCEPT
================================

I was asked the question; “Why would I be interested in letting a PC do router functions?” to which I did not give an adequate response. The short answer is that not everyone will be interested and possibly most will leave all such things to a router and that router might just have all the options we need, but there is always the chance that some of us will find a router lacking in some areas and may want to transfer some, if not all, router functions to a PC. Whether it’s a small low power machine such as a Raspberry PI, or an old laptop, or maybe even the desktop PC we use for normal day to day tasks, everyone’s wants / needs vary to one degree or another.

There are router / firewall distributions that make all this a bit easier such as iPcop, Smothwall, SME Service, pfSense, IPFire, Endian [just to name a few]. There will always be some of us that prefer the learning experience of a roll-your-own approach. I suppose the main reason someone would want to do this is simply; “Because I can”! But there are a few features we may not find fully supported in many off-the-shelf routers, such as policy-based routing, load balancing, traffic shaping / quality of service, multiple uplinks, uplink failover, demilitarized zone, intrusion detection / intrusion prevention, web ftp and E-Mail antivirus, antispam, and content filtering. It boils down to the rather attractive notion of having a full featured Router / Firewall that goes beyond what most routers will do. Now we may not need all the features I listed above but just one or two may be all it takes to spark this type of venture, (and the above list is not totally complete either, I’m sure I left some out).
Just to be able to say, “I built my own”, may be all it takes.

The main interest is the Firewall aspect and not just any old firewall but one that is fully customizable. Building a NAT Firewall puts lots of advanced routing features at our disposal.

Let’s say we want to redirect port 25 mail server traffic to a mail server of our choosing and you want to block everyone except traffic from your own mail server from sending traffic out. Maybe you want to block outside access for a particular IP maybe even incoming and outgoing traffic for security purposes so that it’s only able to communicate within your LAN. Maybe you want to block an outside IP, or a range of outside IP’s. Maybe you want to block ping requests to one PC or another or to block incoming ping requests to all. Maybe you want to redirect a certain port to a non-standard one to some server you may have. Experimenting and learning iptables and network address translation can be interesting.

Building your own router may just be an experiment or sort of a hobby, [just for fun], but it may turn out to be useful in one way or another – in other words, it may turn out to have some practical aspects.

 

October 12th Meeting - Raspberry Pi

Meeting location:   VFW 8235 - 5333 White Settlement Rd.

.

Schedule

  • 10am Start
  • 10:15 Presentation on Raspberry Pi by Terry Henderson
 

Saturday, September 10th Meeting

Schedule

10:30 - Meeting starts
  • Presentation: Using puppet to configure multiple Linux server - David Miller

Location

This meeting will be held in the Chappell Meeting Room of the Fort Worth Central Library.
 
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