What's changed: Initial version (topic 1.04, subtopics 1.04.1–1.04.4)
4.3Package Management with yum
Learn repository-based package management on RHEL-family systems: install/update/remove/search with yum, finding the package that provides a file (provides), repository configuration (/etc/yum.repos.d/, /etc/yum.conf), and download-only fetching with yumdownloader.
On RPM-family distributions (RHEL, CentOS, AlmaLinux), yum plays apt's role (its successor dnf keeps compatible usage). Same job—fetch from repositories, manage with dependencies—so learn it as a mapping from apt.
4.3.1Core yum operations
- Install with
yum install httpd; remove withyum remove httpd; update withyum update(everything, or one package by name); search withyum search keyword; details withyum info pkg. - File → package lookup with
yum provides /usr/sbin/httpd(covers uninstalled packages). List withyum list installed. - Repositories are defined by
.repofiles in /etc/yum.repos.d/ (one section per repo); global settings in /etc/yum.conf. Check enabled repos withyum repolist. - yumdownloader downloads rpm files without installing—for offline transfer or inspection.
Staples: package providing a file = yum provides, repo definitions = .repo files in /etc/yum.repos.d/, download only = yumdownloader. The apt mapping is the favorite confusion: yum update upgrades packages, while apt update only refreshes the index.
Exams target the asymmetry with apt. apt splits "update = index, upgrade = packages" into two words, but yum's update means "upgrade packages"—index refresh happens automatically each run (explicitly: yum makecache). So "ran yum update" = "packages were upgraded"; reading it with apt intuition gets you the wrong answer. Repo management differs too: apt lists everything in one sources.list, while yum drops one .repo file per repository into /etc/yum.repos.d/, toggled by enabled=1/0. Adding a corporate mirror is just placing one .repo file. yumdownloader is the staple for distributing rpms to air-gapped servers or inspecting before installing; --resolve also fetches dependent rpms.
| Goal | Debian family (apt) | RHEL family (yum) |
|---|---|---|
| Install | apt install | yum install |
| Upgrade packages | apt update → apt upgrade | yum update (index auto) |
| File → package | apt-file search | yum provides |
| Repo definitions | /etc/apt/sources.list | /etc/yum.repos.d/*.repo |
Trap: "yum update, like apt update, only refreshes the index" is wrong—yum update upgrades packages (the index refreshes automatically). Distribution mix-ups like "yum repos are defined in /etc/apt/sources.list" are classic distractors too (correct: /etc/yum.repos.d/).
4.3.2Section summary
- yum update = upgrade packages (index auto-refreshes); install/remove/search/info/list installed
- provides = file lookup, /etc/yum.repos.d/ = per-repo .repo files, yumdownloader = download only
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Quick check
(just a quick review)Q1. On a RHEL-family server, you want to find which package provides /usr/sbin/httpd. Which command?
Q2. You need rpm files to carry to an offline test server—download only, no install. Which command?
Q3. You want to add a repository for yum. Where do its definition files go?
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