Linux installation

Linux is not one install model—it is a family of distributions each with a package database, optional universal formats, and growing use of immutable /usr and prefix stores. Treat distro variance as first-class when you ship.

Overview: Installation architecture. How-to: App installer packaging · Unix/macOS auto-updates.

FHS vs what distros actually do

The Filesystem Hierarchy Standard still names the mental map:

  • /usr/bin, /usr/lib, /etc, /var/lib

  • /opt/<vendor> for large third-party trees

Reality checks:

  • usrmerge — /bin and /sbin symlinks into /usr on Debian/Fedora-class distros; scripts hard-coding /bin/bash still work but packaging assumptions shift.

  • /opt — common for proprietary IDEs and browsers; some vendors skip distro packages entirely.

  • ~/.local — user installs (pip install --user, static binaries, linuxbrew) without root.

  • Read-only or image-based /usr — Fedora Silverblue, Ubuntu Core, immutable variants: you do not “drop files into /usr/bin” on the running system; you layer packages or use Flatpak.

SUS/FHS documents the distro package contract well; it under-describes Flatpak namespaces, Snap mounts, and Nix store paths.

deb and rpm ecosystems

Family Notes

Debian/Ubuntu (.deb)

dpkg file lists, maintainer scripts, alternatives, systemd unit enablement; apt lock during transactions.

Fedora/RHEL (.rpm)

rpm + dnf; %files, scriptlets, SELinux contexts; similar lock semantics.

Arch (pacman)

Simple archive + hooks; rolling release changes ABI assumptions.

Alpine (apk)

musl; common in containers; different libc story for prebuilt binaries.

Targeting “Linux” for a GUI app usually means pick distros or ship Flatpak/AppImage, not one .deb that silently works everywhere.

Flatpak, Snap, AppImage

Format Tradeoff sketch

Flatpak

OSTree refs, runtimes, portals for file access; Flathub distribution; user or system install.

Snap

Canonical store/channel model; auto-update daemon; mount namespace.

AppImage

Single file, FUSE or extract; weak system integration unless you add desktop files and optional appimaged; popular for CI artifacts.

Universal formats solve glibc/musl and dependency skew at the cost of size, startup, and integration (themes, host file pickers, Wayland/X11 edge cases).

Nix and Guix

Nix and Guix treat installs as pure store paths (/nix/store/…​) with profiles generating /usr symlinks. They excel at reproducibility and multi-version toolchains; they break assumptions in apps that hard-code /usr/lib or mutate global config. Great for dev machines; niche for casual GUI users unless you ship a nix flake.

Containers

OCI images are the install model for services, not a substitute for desktop integration. Bind-mounting host $HOME into a dev container blurs “installed on host” vs “installed in image”—document which side owns upgrades.

systemd

Long-running daemons ship unit files under /etc/systemd/system or /usr/lib/systemd/system. systemctl enable --now is the modern “install service” step; uninstall must disable and remove units. User services (systemd --user) suit per-user agents without root.

XDG Base Directory

User-writable roles (parallel to macOS Library folders):

  • XDG_CONFIG_HOME — config

  • XDG_DATA_HOME — application data

  • XDG_CACHE_HOME — cache

  • XDG_STATE_HOME — state (logs, history)

Desktop entries: ~/.local/share/applications/*.desktop for GUI discovery. Respect XDG when you ship tarball or AppImage so uninstall and backup stories stay sane.

Distro variance as first-class

When planning support, name concrete targets:

  • LTS deb (e.g. Ubuntu 22.04/24.04) + optional Flatpak

  • Fedora current + Flathub

  • Whether musl/Alpine is in scope for static binaries only

Package maintainers will split your upstream into patches; CI should not assume one apt install line covers “Linux.”

Concurrency

dpkg/apt locks differ from Flatpak and from curl | sh vendor scripts. Agent hosts need an outer mutex across managers (OS install concurrency).

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