My YUM and DNF cheatsheet

Used by RPM, and since CentOS is "Community Enterprise OS" which is a fork of off Red Hat Enterprise, it makes sense that CentOS would be using YUM. However, YUM had some performance issues, so has been getting replaced by Dandified YUM, or DNF or just Dandified. See 2daygeek

In fact readthedoc.io claims that the next major release of YUM is DNF.

dnf list –installed dnf install tcshhiishi

We can specify a new repository by manually editing or creating a new .repo file in the /etc/yum.repos.d directory, however we can much more easily create a persistent repository with the dnf config-manager command.

• dnf config-manager --add-repo"https://mirror.aarnet.edu.au/pub/centos/7"
• dnf config-manager --add-repo"https://mirror.aarnet.edu.au/pub/centos/7"

Adding repo from: https://mirror.aarnet.edu.au/pub/centos/7

• dnf config-manager --set-enabled PowerTools # this failed
• dnf config-manager --set-enabled powertools # this worked
• dnf config-manager --set-enabled powertools

followed by confirmation:

• dnf repolist

cat /etc/yum.repos.d/mirror.aarnet.edu.au_pub_centos_7.repo [mirror.aarnet.edu.au_pubcentos7] name=created by dnf config-manager from https://mirror.aarnet.edu.au/pub/centos/7 baseurl=https://mirror.aarnet.edu.au/pub/centos/7 enabled=1

We simply provide a known repository URL in the –add-repo option, and this creates a .repo file based on the name of the repository URL specified. In this case, /etc/yum.repos.d/mirror.aarnet.edu.au_{pubcentos7.repo} has been created with the contents specified above in the output of the command. We can now install or update packages from this newly specified mirror.

The following command also seemed to add a repo. Not sure if this is the same thing or a different approach to "–add-repo"

• dnf install https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm

rpm -qa | grep epel
get the output then:
yum remove epel-release-5-4
yum clean all

root@zinux ~[606]$
dnf install dnf-plugins-core
Last metadata expiration check: 0:53:35 ago on Tue 20 Apr 2021 03:38:29 PM EDT.
Package dnf-plugins-core-4.0.17-5.el8.noarch is already installed.
Dependencies resolved.
Nothing to do.
Complete!
root@zinux ~[607]$
dnf config-manager --set-enabled powertools
root@zinux ~[608]$

root@zinux /etc/yum.repos.d[618]$
grep "enabled=" *.repo
CentOS-Linux-AppStream.repo:enabled=1
CentOS-Linux-BaseOS.repo:enabled=1
CentOS-Linux-ContinuousRelease.repo:enabled=0
CentOS-Linux-Debuginfo.repo:enabled=0
CentOS-Linux-Devel.repo:enabled=0
CentOS-Linux-Extras.repo:enabled=1
CentOS-Linux-FastTrack.repo:enabled=0
CentOS-Linux-HighAvailability.repo:enabled=0
CentOS-Linux-Media.repo:enabled=0
CentOS-Linux-Media.repo:enabled=0
CentOS-Linux-Plus.repo:enabled=0
CentOS-Linux-PowerTools.repo:enabled=1
CentOS-Linux-Sources.repo:enabled=0
CentOS-Linux-Sources.repo:enabled=0
CentOS-Linux-Sources.repo:enabled=0
CentOS-Linux-Sources.repo:enabled=0
root@zinux /etc/yum.repos.d[619]$

To add a repository we use: sudo dnf –add-repo <reponame>

To enable repository transiently: sudo dnf –enablerepo=<reponame> sudo dnf enable the PowerTools repo with dnf –enablerepo=PowerTools

To disable repository transiently: sudo dnf –disablerepo=<reponame>

To disable repository permanently: sudo dnf config-manager –set-disabled <reponame>

To enable repository permanently: sudo dnf config-manager –set-enabled <reponame>

To remove a repository, first check if a package used is part of the repo then if not, can simply delete the file in /etc/yum.repos.d/*.repo

Are available here: rootusers.com

See the pdf.

 zintis@c8host ~$ sudo dnf info qemu-kvm qemu-img virt-manager libvirt libvirt-python
 Installed Packages
 Name         : qemu-img
 Epoch        : 15
 Version      : 2.12.0
 Release      : 65.module_el8.0.0+189+f9babebb.5
 Arch         : x86_64
 Size         : 4.7 M
 Source       : qemu-kvm-2.12.0-65.module_el8.0.0+189+f9babebb.5.src.rpm
 Repo         : @System
 From repo    : Aptream
 Summary      : QEMU command line tool for manipulating disk images
 URL          : http://www.qemu.org/
 License      : GPLv2 and GPLv2+ and CC-BY
 Description  : This package provides a command line tool for manipulating disk images.

 Name         : qemu-kvm
 Epoch        : 15
 Version      : 2.12.0
 Release      : 65.module_el8.0.0+189+f9babebb.5
 Arch         : x86_64
 Size         : 0.0  
 Source       : qemu-kvm-2.12.0-65.module_el8.0.0+189+f9babebb.5.src.rpm
 Repo         : @System
 From repo    : AppStream
 Summary      : QEMU is a machine emulator and virtualizer
 URL          : http://www.qemu.org/
 License      : GPLv2 and GPLv2+ and CC-BY
 Description  : qemu-kvm is an open source virtualizer that provides hardware
              : emulation for the KVM hypervisor. qemu-kvm acts as a virtual
	      : machine monitor together with the KVM kernel modules, and emulates the
	      : hardware for a full system such as a PC and its associated peripherals.

 Available Packages
 Name         : libvirt
 Version      : 4.5.0
 Release      : 24.3.module_el8.0.0+189+f9babebb
 Arch         : x86_64
 Size         : 26 k
 Source       : libvirt-4.5.0-24.3.module_el8.0.0+189+f9babebb.src.rpm
 Repo         : AppStream
 Summary      : Library providing a simple virtualization API
 URL          : https://libvirt.org/
 License      : LGPLv2+
 Description  : Libvirt is a C toolkit to interact with the virtualization capabilities
              : of recent versions of Linux (and other OSes). The main package includes
	      : the libvirtd server exporting the virtualization support.

 Name         : virt-manager
 Version      : 2.0.0
 Release      : 5.1.el8
 Arch         : noarch
 Size         : 365 k
 Source       : virt-manager-2.0.0-5.1.el8.src.rpm
 Repo         : AppStream
 Summary      : Desktop tool for managing virtual machines via libvirt
 URL          : https://virt-manager.org/
 License      : GPLv2+
 Description  : Virtual Machine Manager provides a graphical tool for administering virtual
              : machines for KVM, Xen, and LXC. Start, stop, add or remove virtual devices,
              : connect to a graphical or serial console, and see resource usage statistics
              : for existing VMs on local or remote machines. Uses libvirt as the backend
              : management API.

zintis@c8host ~$ ^C
zintis@c8host ~$ sudo dnf upgrade qemu-kvm qemu-img virt-manager libvirt libvirt-python
CentOS-8 - AppStream                                                                            2.1 kB/s | 4.3 kB     00:02    
CentOS-8 - Base                                                                                 1.7 kB/s | 3.9 kB     00:02    
CentOS-8 - Extras                                                                               687  B/s | 1.5 kB     00:02    
Adobe Systems Incorporated                                                                      2.6 kB/s | 2.9 kB     00:01    
Package virt-manager available, but not installed.
No match for argument: virt-manager
Package libvirt available, but not installed.
No match for argument: libvirt
No match for argument: libvirt-python
Dependencies resolved.
Nothing to do.
Complete!
zintis@c8host ~$ 

echo "exclude=firefox" >> /etc/dnf/dnf.conf

see centos.org wiki for details on repositories.

/etc/dnf/dnf.conf /etc/dnf/dnf.repos.d

/etc/yum.conf (is actually a symlink to /etc/dnf/dnf.conf)

This taken right out of opensource.com:

CLI commands that differ in DNF and yum Following are some of the changes to yum's command-line interface (CLI) you will find in DNF.

• dnf update or dnf upgrade: Executing either dnf update or dnf upgrade has the

same effect in the system: both update installed packages. However, dnf upgrade is preferred since it works exactly like yum –obsoletes update.

• resolvedep: This command doesn't exist in DNF. Instead, execute dnf provides

to find out which package provides a particular file.

• deplist: Yum's deplist command, which lists RPM dependencies, was removed in

DNF because it uses the package-dependency solver algorithm to solve the dependency query.

• dnf remove <package>: You must specify concrete versions of whatever you want

to remove. For example, dnf remove kernel will delete all packages called "kernel," so make sure to use something like dnf remove kernel-4.16.x.

• dnf history rollback: This check, which undoes transactions after the one you

specifiy, was dropped since not all the possible changes in the RPM Database Tool are stored in the history of the transaction.

• –skip-broken: This install command, which checks packages for dependency

problems, is triggered in yum with –skip-broken. However, now it is part of dnf update by default, so there is no longer any need for it.

• -b, –best: These switches select the best available package versions in

transactions. During dnf upgrade, which by default skips over updates that cannot be installed for dependency reasons, this switch forces DNF to consider only the latest packages. Use dnf upgrade –best.

• –allowerasing: Allows erasing of installed packages to resolve

dependencies. This option could be used as an alternative to the yum swap X Y command, in which the packages to remove are not explicitly defined.

For example: dnf –allowerasing install Y.

• –enableplugin: This switch is not recognized and has been dropped.

DNF Automatic The DNF Automatic tool is an alternative CLI to dnf upgrade. It can execute automatically and regularly from systemd timers, cron jobs, etc. for auto-notification, downloads, or updates.

To start, install dnf-automatic rpm and enable the systemd timer unit (dnf-automatic.timer). It behaves as specified by the default configuration file (which is /etc/dnf/automatic.conf).

dnf-automatic-timer.png Result of # systemctl enable dnf-automatic.timer Other timer units that override the default configuration are listed below. Select the one that meets your system requirements.

dnf-automatic-notifyonly.timer: Notifies the available updates dnf-automatic-download.timer: Downloads packages, but doesn't install them dnf-automatic-install.timer: Downloads and installs updates Basic DNF commands useful for package management

yum-install-dnf.png Output of # yum install dnf

dnf-version.png Output of # dnf –version

dnf-list-kernel.png Output of # dnf list kernel command

dnf-check-update.png Output of # dnf check-update kernel

dnf-search.png Output of # dnf search

dnf-repolist.png Output of # dnf repolist all

dnf-list-recent.png Output of # dnf list –recent

dnf-updateinfo-list-available-sec.png OUtput of # dnf updateinfo list available sec

dnfupdateinfo-severity-critical.png Output of # dnf updateinfo list available sec –sec-severity Critical

dnf-updateinfo-fedora.png Output of # dnf updateinfo FEDORA

dnf-upgrade-security.png Output of # dnf upgrade –security Summary These are just a small number of DNF's features, changes, and commands. For complete information about DNF's CLI, new plugins, and hook APIs, refer to the DNF guide.

systemctl list-units –type target –all

dnf grouplist -v –hidden