Package management

Check available security updates for CentOS 7.

Today, I will show you how to manage RPM keyring on the CentOS operating system using a real life example.

Alter configuration for specific yum repository.

List packages in specific yum repository.

Disable specific yum repository to prevent particular packages from installation or update.

Use yum without downloading or updating its metadata.

Downgrade package using yum.

Download RPM packages from YUM repository using additional yum utilities.

Create simple artificial package to work around missing dependencies,

Create simplest possible meta-package to install multiple software packages at once and quickly setup familiar environment.

Display reverse dependencies to inspect which packages depend on given application or library.

There are those rare situations where you do not know the public key required to verify repository signatures but want to add a repository and a public key used to sign it. Hopefully, there is an easy answer to that question.

Configuring and using additional repositories requires APT public key management to validate the Release file and downloaded packages.

Display dependencies to inspect which packages are required for a given application.

Enable HTTPS (Hypertext Transfer Protocol Secure) for package managers using libapt-pkg library.

Query APT configuration to inspect specific options or create universal Debian utilities.

Backports repository provides packages for stable system that are recompiled from testing or unstable distribution. It is important to know that these packages are provided as is without any security support guarantee.

Remove package dependencies that are now no longer needed and configure system to perform this task automatically.

The init-system-helpers package that provides a helper tools for all init systems is not available in primary Debian Wheezy repositories. You need to use wheezy-backports repository to install it on that operating system.

Keeping an eye on a constantly changing APT cache can be quite tedious, so automate this task and free up your time to focus on other projects.

Clear the APT cache to reclaim disk space used by the downloaded packages.

Disable APT cache to conserve disk space on a small Debian based embedded system or a custom-built live USB system that can be easily booted.

HPE Software Delivery Repository is cryptographically signed, so you can be sure that provided software packages have not been modified by a third party. However, sometimes you can encounter the The following signatures couldn't be verified because the public key is not available error which can be easily fixed.

There are many applications that share the same source package, so I will show three different ways to print the name of the source package.

Knowing how to determine when the last time package index files were updated can be beneficial when you least expect it. It is not something used every day but can be used to monitor or verify when apt-get update command was executed.

It is very easy to upgrade the whole Debian system, but you can also upgrade only selected packages and skip the rest.

Many years ago I wrote How to display available updates blog post which mainly related to Debian Wheezy. Today I want to extend it by a neat console friendly utility available in Debian Jessie since the milestone apt release thanks to Michael Vogt.

Today, I will explain how to automatically choose nearest mirror based on geographic and network location using Debian mirrors HTTP redirector to solve the common problem of choosing an appropriate mirror.

Sometimes I need to check the installed package version, compare it with the available version, or verify that the correct version is already installed. I will show you how to quickly perform these checks.

There are plenty of off-line Debian systems just waiting to update index files, upgrade or install additional packages. This can be easily achieved by using apt-offline utility. I will shortly describe common usage scenario as it is very handy application.

It is good to know how to tell to which package the specified file belongs to as this knowledge could be very useful during system upgrade or unexpected system failure.

If you ever wondered about how to backup list of installed packages and then restore it on another machine then you need to know that it does not require anything more then three basic utilities – dpkg to import/export list of packages, apt-get to install selected packages and apt-mark to restore extended package states.

Generally I prefer to install Debian using minimal CD so Apt-Cacher NG is an integral part of this process as I don’t like to wait during installation process.

I am currently using cellular connection most of the time. Thus, it is obvious that I prefer to reduce the amount of data transferred over the network. Significant portion of it is reduced by the apt caching proxy apt-cacher-ng as I use Debian Linux distribution and VirtualBox on daily basis.

It is straightforward to display available updates using an application with a graphical user interface, but not so obvious to do it by using shell commands only. I will shed some useful light on the subject so we could both benefit from it.

There are at least couple ways to hold specific package and prevent it from being updated as you can use apt, dpkg, aptitude, dselect, apt preferences, but only the last one is effective in every case.

If you downloaded deb package and wonder how to install it then just look at the snippet posted below.

Exclude package from an update on CentOS operating system.

Get rid of slow CentOS mirrors on update.