| | {{infobox |
| | | title = Package Management |
| | | chapter = Linux Handbook, chapter 20 — packages, dependencies, and the managers |
| | | core | A package = files + metadata + install scripts; the manager resolves the graph |
| | | managers | apt (Debian) · dnf (Fedora) · pacman (Arch) · pkgtools (Slackware) · xbps (Void) |
| | | skills | install/remove/search · the dependency graph · the formats |
| | | next | Disks & storage — where the packages land |
| | }} |
| | |
| | **A package manager is the distro's real identity** — apt makes Debian, pacman makes Arch, pkgtools makes Slackware. The package itself is simple: an archive of files + metadata (name, version, deps) + install hooks. The manager's work is resolving **dependency graphs** — installing `foo` pulls `libfoo` and `libbar` transitively — and tracking who owns every file on the system. This chapter covers the formats, the managers, and the operations every distro shares. |
| | |
| | ## The formats |
| | |
| | ```sh |
| | file package.deb # Debian — ar archive of tarballs + control |
| | file package.rpm # Red Hat — cpio + metadata |
| | file package-1.0-x86_64-1.txz # Slackware — a tar.xz with install/doinst.sh |
| | file package.pkg.tar.zst # Arch — zstd tar |
| | ``` |
| | |
| | Each format is an archive + a control layer: name, version, arch, dependencies, install/uninstall scripts. `dpkg-deb -x pkg.deb dir` extracts a .deb by hand; `rpm2cpio pkg.rpm | cpio -id` does an rpm — the formats are inspectable. |
| | |
| | ## The managers — the operations every distro shares |
| | |
| | | Operation | apt (Debian/Ubuntu) | dnf (Fedora) | pacman (Arch) | pkgtools (Slackware) | |
| | | --- | --- | --- | --- | --- | |
| | | update indexes | `apt update` | `dnf check-update` | `pacman -Sy` | `slackpkg update` | |
| | | upgrade all | `apt upgrade` | `dnf upgrade` | `pacman -Syu` | `slackpkg upgrade-all` | |
| | | install | `apt install x` | `dnf install x` | `pacman -S x` | `installpkg x.txz` / `slackpkg install` | |
| | | remove | `apt remove x` | `dnf remove x` | `pacman -R x` | `removepkg x` | |
| | | search | `apt search x` | `dnf search x` | `pacman -Ss x` | `slackpkg search x` | |
| | | info | `apt show x` | `dnf info x` | `pacman -Si x` | `slackpkg info x` | |
| | | files owned | `dpkg -L x` | `rpm -ql x` | `pacman -Ql x` | `less /var/log/packages/x` | |
| | | owner of a file | `dpkg -S /path` | `rpm -qf /path` | `pacman -Qo /path` | `grep /path /var/log/packages/*` | |
| | | clean cache | `apt clean` | `dnf clean all` | `pacman -Sc` | — | |
| | |
| | The four patterns map one-to-one — learn one, know them all. |
| | |
| | ## The dependency graph — the manager's real job |
| | |
| | ```sh |
| | apt-cache depends x # what x needs |
| | apt-cache rdepends x # what needs x — the why-is-it-installed answer |
| | apt autoremove # orphans — deps nothing needs anymore |
| | ``` |
| | |
| | Every package declares `Depends:` — the manager topologically sorts them, installs in order, and tracks *why* each is present (explicitly-installed vs dependency). `autoremove` reaps the orphans — the housekeeping command worth knowing. |
| | |
| | ## The repository layer |
| | |
| | Managers fetch from **repositories** — signed, indexed collections: `/etc/apt/sources.list` + `sources.list.d/` (Debian), `/etc/yum.repos.d/` (Fedora), `/etc/pacman.conf` + mirrorlist (Arch), `slackpkg`'s mirror. The repo is the distro's curated world — adding third-party repos (`ppa`, COPR, AUR-adjacent) is the standard way software outside the core arrives. `apt update` refreshes the index; the index is what `search` searches. |
| | |
| | ## The deeper operations |
| | |
| | ```sh |
| | # apt — the full surface |
| | apt list --installed | wc -l # how many packages |
| | apt list --upgradable # what would change |
| | apt list --all-versions x # every version available |
| | apt depends x / apt rdepends x # the graph both ways |
| | apt download x # the .deb without installing |
| | apt hold x / apt unhold x # pin — never upgrade |
| | apt-mark showmanual / showauto # explicitly vs dep-installed |
| | apt-cache policy x # versions + sources + pin weights |
| | apt-get source x # the source |
| | apt-get build-dep x # its build deps |
| | apt-get -f install # the repair command |
| | dpkg-reconfigure x # re-run a package's config |
| | dpkg --listfiles x; dpkg --search /path |
| | dpkg -i local.deb # manual install |
| | dpkg --configure -a # fix interrupted |
| | apt clean; apt autoremove --purge # hygiene |
| | apt purge x # remove + its configs |
| | |
| | # dnf — same grammar |
| | dnf list installed |
| | dnf provides /path # who provides a file |
| | dnf repoquery --requires x # the deps |
| | dnf history # every transaction — and undo |
| | dnf history undo 5 # REVERSE a transaction |
| | dnf check-update |
| | dnf config-manager --add-repo url |
| | dnf remove --duplicates |
| | dnf versionlock add x # pin |
| | |
| | # pacman |
| | pacman -Qqe # explicitly installed |
| | pacman -Qtd # orphans — the autoremove list |
| | pacman -Rns x # remove + unneeded deps + configs |
| | pacman -Qkk x # verify files vs manifest |
| | pacman -F file # which package provides a file |
| | pacman -Sc / -Scc # cache hygiene |
| | ``` |
| | |
| | ## The pinning + priority layer |
| | |
| | ```sh |
| | # /etc/apt/preferences — Debian pinning: |
| | Package: firefox |
| | Pin: release a=stable |
| | Pin-Priority: 900 |
| | |
| | apt policy # the weights |
| | apt-mark hold pkg # freeze |
| | ``` |
| | |
| | Priorities decide which repo's version wins; `hold` freezes a package against upgrade — the tools for mixed-source setups. |
| | |
| | ## The verify layer — trust |
| | |
| | ```sh |
| | apt policy x # versions + where from |
| | apt-key / gpg keys # repo signatures — apt verifies automatically |
| | rpm --checksig pkg.rpm # verify an rpm's signature |
| | pacman-key --verify pkg.sig # arch's signatures — pacman verifies automatically |
| | sha256sum pkg.txz # the checksum layer |
| | ``` |
| | |
| | Packages are signed; the manager verifies before installing. `apt`'s "NO_PUBKEY" errors are the signature layer objecting — the fix is adding the repo's key, never `--allow-unauthenticated`. |
| | |
| | ## The file-ownership queries — the underrated powers |
| | |
| | ```sh |
| | dpkg -S /usr/bin/ls # which package owns this file |
| | dpkg -L coreutils # every file this package installed |
| | apt-file search libfoo.so # which package WOULD provide it |
| | rpm -Va # verify ALL installed files against the manifest |
| | ``` |
| | |
| | `dpkg -S`/`rpm -qf`/`pacman -Qo` answer "where did this file come from"; `rpm -Va` audits the whole system against its manifests — the forensic tool. |
| | |
| | ## Source + foreign packages |
| | |
| | ```sh |
| | apt source x # fetch the source |
| | apt build-dep x # install everything needed to build it |
| | alien pkg.rpm # convert rpm→deb — last resort |
| | checkinstall make install # wraps source installs as packages |
| | snap/flatpak/appimage # the sandboxed universal formats |
| | ``` |
| | |
| | `apt build-dep` + `apt source` + `make` is the clean path from "installed" to "rebuilt myself" — the bridge between chapter 16's liturgy and the distro world. |
| | |
| | ## Where package management goes wrong |
| | |
| | | Symptom | Cause | |
| | | --- | --- | |
| | | `NO_PUBKEY` warnings | Missing repo signing key — add it, don't bypass | |
| | | `E: unable to locate` | `apt update` stale — refresh the index | |
| | | Broken after interrupted upgrade | `dpkg --configure -a` / `apt -f install` — repair | |
| | | A file exists but no package owns it | Manually installed — `/usr/local` hygiene | |
| | | `autoremove` wants to remove something needed | It's a dep — mark it explicitly-installed | |
| | | Third-party repo broke upgrades | Pinning priorities — `apt policy` shows the weights | |
| | |
| | ## Exercises |
| | |
| | 1. `dpkg -S $(which ls)` — who owns `ls`. |
| | 2. `apt-cache rdepends` a library — see who needs it. |
| | 3. `apt policy` a package — read the version weights. |
| | 4. `apt source` something small — read a Debian package's source. |
| | 5. `rpm -qf`/`pacman -Qo`/`slackpkg` equivalents on another family — same questions, different syntax. |
| | |
| | ## See also |
| | |
| | - [[Linux]] · [[Building from source]] · [[Getting Linux]] · [[Inside a Linux System]] |
| | |
| | [[Category:Linux]] |
| | [[Category:Handbook]] |
| | [[Category:Packages]] |
| + | [[Category:Linux Handbook]] |
| | |
