dnf and the RHEL side

The two-layer model is identical across distro families. On Debian/Ubuntu: apt (front-end) → dpkg (engine). On RHEL/Fedora: dnf (front-end) → rpm (engine). The same separation of concerns applies — dnf resolves dependencies and manages repositories, rpm manages the local database and file installation.

# RHEL/Fedora equivalents of common apt workflows
sudo dnf check-update          # check for updates (does not install)
sudo dnf upgrade               # install all available updates
sudo dnf install nginx         # install nginx
sudo dnf remove nginx          # remove nginx
dnf info nginx                 # show version, size, description

One behavioural difference: dnf upgrade automatically runs the equivalent of apt update first — it refreshes the cache before checking for upgrades. You do not need to run dnf check-update separately before dnf upgrade.

Repository configuration lives in /etc/yum.repos.d/*.repo files. The format is INI, similar to systemd unit files:

# /etc/yum.repos.d/nginx.repo
[nginx-stable]
name=nginx stable repo
baseurl=http://nginx.org/packages/centos/$releasever/$basearch/
gpgcheck=1
enabled=1
gpgkey=https://nginx.org/keys/nginx_signing.key
module_hotfixes=true

Key fields: baseurl (or mirrorlist), gpgcheck=1 (verify signatures — always keep this 1), enabled=1/0 (toggle without deleting), gpgkey (URL or path to the GPG key).

# Add a repo from a .repo file
sudo dnf config-manager --add-repo https://example.com/package.repo

# List enabled repositories
dnf repolist

# List all repos including disabled
dnf repolist --all

# Enable/disable a repo by ID
sudo dnf config-manager --set-enabled nginx-stable
sudo dnf config-manager --set-disabled nginx-stable

The $releasever and $basearch variables are expanded by dnf at runtime — $releasever becomes 9 on RHEL 9, and $basearch becomes x86_64 or aarch64 depending on the system. This makes a single .repo file work across major versions.

rpm is the low-level engine — the dpkg equivalent. All installed package metadata lives in /var/lib/rpm/ (an SQLite database, unlike dpkg’s plain-text format). The query flags mirror dpkg’s:

# List all installed packages
rpm -qa

# Which package owns this file?
rpm -qf /usr/bin/nginx

# List all files installed by nginx
rpm -ql nginx

# Verify nginx files against the RPM database (detects tampering)
rpm -V nginx
# Output format: SM5DLUGTP  c /etc/nginx/nginx.conf
# S=size, M=mode, 5=md5, D=device, L=symlink, U=user, G=group, T=mtime

# Install a local .rpm file (rpm has no dependency resolution — use dnf when possible)
sudo rpm -ivh ./package-1.0.x86_64.rpm
# -i=install, -v=verbose, -h=hash progress bars

Like dpkg, rpm -i does no dependency resolution. If a .rpm requires libfoo, you must install libfoo first or use dnf localinstall ./package.rpm which calls rpm but also resolves dependencies from configured repos.

AppStream modules are a RHEL/CentOS Stream concept with no direct apt equivalent. They let you install multiple versions of the same software stream (e.g. nginx 1.20 stable vs 1.24 mainline) without adding a third-party repo. This is RHEL’s answer to Ubuntu’s PPAs.

# List available module streams for nginx
dnf module list nginx
# Name   Stream         Profiles    Summary
# nginx  mainline [d]   common [d]  A high performance web server
# nginx  1.22           common      ...

# Enable a specific stream (locks the version stream)
sudo dnf module enable nginx:mainline

# Install from the enabled stream
sudo dnf module install nginx

# Check which stream is active
dnf module list nginx | grep '\[e\]'   # [e] = enabled, [d] = default, [i] = installed

# Switch streams (requires a reset first)
sudo dnf module reset nginx
sudo dnf module enable nginx:1.22
sudo dnf module install nginx

AppStream modules exist in /etc/dnf/modules.d/. When a stream is enabled, dnf will not automatically switch to a newer stream on dnf upgrade — stream switching is explicit, preventing surprise major-version upgrades.

The RHEL family tree: RHEL → CentOS Stream → Fedora. Understanding which you are on affects how you add repositories and what packages are available.

Fedora (cutting-edge, 6-month release cycle)
    ↓ features flow downstream after stabilization
CentOS Stream (rolling preview of next RHEL minor release)
    ↓ cherry-picked, tested, hardened
RHEL (Red Hat Enterprise Linux — paid support, 10-year lifecycle)
    ↓ binary-compatible rebuilds
AlmaLinux / Rocky Linux / Oracle Linux (free RHEL rebuilds)

# Check which distro and version you are on
cat /etc/os-release
# ID=rhel / fedora / centos
# VERSION_ID=9.3

# RHEL requires a subscription to access base repos
subscription-manager register --username=user --password=pass

# On AlmaLinux/Rocky (RHEL rebuilds, no subscription needed)
dnf install epel-release   # Extra Packages for Enterprise Linux

EPEL (Extra Packages for Enterprise Linux) is the RHEL equivalent of Ubuntu’s universe component — community-maintained packages not in RHEL’s official repos. If you cannot find a package via dnf search, add EPEL first.