Master yum: Install, Remove, and Manage Packages on CentOS Efficiently

yum is a powerful command‑line tool for managing packages on CentOS and other RPM‑based systems. You can install a package such as the C++ compiler with yum install gcc-c++, then verify the installation using rpm -qa | grep gcc-c++.

To see all available versions of a package, run yum list *gcc-c*, and to remove it, use yum remove gcc-c++.

yum Repositories

A yum repository (repo) is a storage location for RPM packages. The configuration files for repos are stored in /etc/yum.repos.d/ with a .repo extension. Each file can define multiple repositories, each identified by a unique name inside square brackets.

Key configuration items include: enabled=1 – enables the repo (0 disables it). gpgkey – location of the GPG key used to verify package signatures. baseurl – the URL of the repository. name – a human‑readable description.

Disabling a repository (e.g., setting enabled=0) prevents yum from using it, which can be useful when troubleshooting dependency issues.

Offline Package Download

If a machine cannot access the internet, you can download RPMs and their dependencies on another system and copy them locally. Install the yum-plugin-downloadonly plugin if needed, then run:

yum install --downloadonly --downloaddir=/tmp/pzqu gcc-c++

The --downloaddir option specifies where the packages are saved.

Postscript

Caching every repository is impractical for most users, but you can create a private repository for your own projects. This allows you to package and distribute your software in an offline environment, a practice that aligns with continuous integration workflows.