Master Linux Package Managers: apt, pacman, and dnf

# search & info
apt search <term>
apt show <pkg>            # detailed info
apt policy <pkg>          # show available versions / pinning

# install / remove
sudo apt install <pkg>
sudo apt remove <pkg>     # keep config files
sudo apt purge <pkg>      # remove with config

# update / upgrade
sudo apt update
sudo apt upgrade          # safe upgrade
sudo apt full-upgrade     # may remove/replace packages (formerly dist-upgrade)

# list things
apt list --installed
apt list --upgradable

# Ubuntu PPA helper (adds repo + key):
sudo add-apt-repository ppa:<owner>/<ppa>
sudo apt update

# Generic (signed-by best practice)
echo "deb [signed-by=/usr/share/keyrings/vendor.gpg] https://repo.example.org stable main" \
 | sudo tee /etc/apt/sources.list.d/vendor.list

curl -fsSL https://repo.example.org/key.gpg | sudo gpg --dearmor -o /usr/share/keyrings/vendor.gpg
sudo apt update

# finish interrupted dpkg configuration
sudo dpkg --configure -a

# fix broken deps
sudo apt --fix-broken install

# release locks (only if no apt/dpkg is running!)
sudo lsof /var/lib/dpkg/lock-frontend /var/lib/apt/lists/lock /var/cache/apt/archives/lock
# if stale: sudo rm -f <lockfile> && sudo dpkg --configure -a

# refresh DB + upgrade everything (Arch discourages partial upgrades)
sudo pacman -Syu

# search & info
pacman -Ss <term>
pacman -Si <pkg>      # repo info
pacman -Qi <pkg>      # local install info
pacman -Qs <term>     # search installed

# install / remove
sudo pacman -S <pkg>
sudo pacman -R <pkg>          # remove keeping deps if still required
sudo pacman -Rns <pkg>        # remove with deps not needed + configs

# query files / ownership
pacman -Ql <pkg>              # list files in package
pacman -Qo /path/to/file      # which package owns this file?

# local file install
sudo pacman -U ./pkgfile.pkg.tar.zst

# refresh metadata + upgrade all
sudo dnf upgrade --refresh

# search & info
dnf search <term>
dnf info <pkg>
dnf list installed
dnf check-update

# install / remove
sudo dnf install <pkg>
sudo dnf remove <pkg>

# history
dnf history
sudo dnf history undo <ID>   # rollback a transaction (when possible)

sudo dnf check
sudo dnf repoquery --duplicated
sudo dnf distro-sync

# prevent a package from upgrading temporarily
echo "<pkg> hold" | sudo dpkg --set-selections
apt-mark showhold
# unhold later:
echo "<pkg> install" | sudo dpkg --set-selections

# install a specific version (see apt policy first)
sudo apt install <pkg>=<version>

# downgrade using a cached package (if still in cache)
ls -t /var/cache/pacman/pkg/<pkg>-*.pkg.tar.zst | head
sudo pacman -U /var/cache/pacman/pkg/<pkg>-<ver>-x86_64.pkg.tar.zst

# list history and rollback a transaction
dnf history
sudo dnf history undo <ID>

# install
sudo apt update
sudo apt install -y nmap

# verify
nmap --version
dpkg -L nmap | head     # files installed by the package

# see what happened (logs)
grep -i nmap /var/log/apt/history.log || true
grep -i nmap /var/log/apt/term.log || true

# remove (keep config) / purge (remove config)
sudo apt remove -y nmap
# sudo apt purge -y nmap

# install (Arch discourages partial upgrades, so do -Syu)
sudo pacman -Syu --needed nmap

# verify
nmap --version
pacman -Ql nmap | head   # files in package

# logs & history
grep -i nmap /var/log/pacman.log || true

# remove (with configs and unneeded deps)
sudo pacman -Rns nmap

# install
sudo dnf install -y nmap

# verify
nmap --version
rpm -ql nmap | head       # files in RPM

# history / logs
dnf history | head
sudo grep -i nmap /var/log/dnf.log || true

# remove
sudo dnf remove -y nmap

#!/usr/bin/env bash
set -Eeuo pipefail

bold() { printf "\033[1m%s\033[0m\n" "$*"; }
ok()   { printf "[OK] %s\n" "$*"; }
warn() { printf "[WARN] %s\n" "$*" >&2; }
err()  { printf "[ERR] %s\n" "$*" >&2; }

pm=""; os=""
command -v apt    >/dev/null 2>&1 && pm="apt"
command -v pacman >/dev/null 2>&1 && pm="pacman"
command -v dnf    >/dev/null 2>&1 && pm="dnf"
os="$(uname -s)"

bold "Package Manager Health Check"
echo "Detected PM: ${pm:-none} | OS: $os"
echo "------------------------------------------"

# 1) Network & DNS
bold "1) Network & DNS"
if getent hosts example.com >/dev/null 2>&1; then
  ok "DNS resolution works (example.com)"
else
  warn "DNS resolution failed (example.com)"
fi
if curl -I -s --max-time 5 https://github.com >/dev/null 2>&1; then
  ok "HTTPS reachability OK (github.com)"
else
  warn "HTTPS check failed (github.com)"
fi
echo

# 2) Locks
bold "2) Locks"
case "$pm" in
  apt)
    for f in /var/lib/dpkg/lock-frontend /var/lib/apt/lists/lock /var/cache/apt/archives/lock; do
      if [ -e "$f" ]; then
        if fuser "$f" >/dev/null 2>&1; then warn "Lock in use: $f"; else warn "Stale lock found: $f"; fi
      fi
    done
    ;;
  pacman)
    f=/var/lib/pacman/db.lck
    [ -e "$f" ] && warn "Lock present: $f" || ok "No pacman lock"
    ;;
  dnf)
    for f in /var/run/dnf.pid /var/run/yum.pid; do
      [ -e "$f" ] && warn "Lock present: $f" || true
    done
    [ ! -e /var/run/dnf.pid ] && [ ! -e /var/run/yum.pid ] && ok "No dnf/yum lock"
    ;;
  *)
    warn "Unknown PM; skipping lock checks"
    ;;
esac
echo

# 3) Repos & Keys
bold "3) Repos & Keys"
case "$pm" in
  apt)
    repos=$(ls -1 /etc/apt/sources.list /etc/apt/sources.list.d 2>/dev/null | wc -l || echo 0)
    keys=$(ls -1 /etc/apt/trusted.gpg.d 2>/dev/null | wc -l || echo 0)
    k2=$(ls -1 /usr/share/keyrings 2>/dev/null | wc -l || echo 0)
    ok "Repo files: $repos | Keyrings: trusted.gpg.d=$keys, /usr/share/keyrings=$k2"
    ;;
  pacman)
    [ -s /etc/pacman.conf ] && ok "pacman.conf present"
    [ -s /etc/pacman.d/mirrorlist ] && ok "mirrorlist present"
    if sudo -n pacman-key --list-keys >/dev/null 2>&1; then
      ok "keyring readable"
    else
      warn "keyring may need init: pacman-key --init && --populate archlinux"
    fi
    ;;
  dnf)
    repos=$(ls -1 /etc/yum.repos.d/*.repo 2>/dev/null | wc -l || echo 0)
    ok "Repo files: $repos"
    if rpm -qa gpg-pubkey >/dev/null 2>&1; then
      ok "RPM GPG keys installed ($(rpm -qa gpg-pubkey | wc -l))"
    else
      warn "No RPM GPG keys detected"
    fi
    ;;
esac
echo

# 4) Cache Size
bold "4) Cache Size"
case "$pm" in
  apt)    dir=/var/cache/apt/archives ;;
  pacman) dir=/var/cache/pacman/pkg ;;
  dnf)    dir=/var/cache/dnf ;;
  *)      dir="" ;;
esac
if [ -n "${dir}" ] && [ -d "${dir}" ]; then
  sz=$(du -sh "${dir}" 2>/dev/null | awk '{print $1}')
  ok "Cache ${dir}: ${sz}"
else
  warn "Cache directory not found"
fi
echo

# 5) Sanity Checks (non-invasive)
bold "5) Sanity Checks"
case "$pm" in
  apt)
    if sudo -n true 2>/dev/null; then
      if sudo apt-get -s upgrade >/dev/null 2>&1; then ok "apt dependency graph OK (dry-run)"; else warn "apt dry-run upgrade reported issues"; fi
    else
      warn "Run with sudo for full apt checks"
    fi
    ;;
  pacman)
    if pacman -Sl >/dev/null 2>&1; then ok "pacman sync DB readable"; else warn "pacman sync DB issue (try: sudo pacman -Syy)"; fi
    ;;
  dnf)
    if sudo -n dnf check >/dev/null 2>&1; then ok "dnf check OK"; else warn "dnf check reported issues"; fi
    ;;
esac

echo
bold "Done."

pm() {
  local action="$1"; shift || true
  if command -v apt >/dev/null 2>&1; then
    case "$action" in
      install) sudo apt update && sudo apt install -y "$@";;
      remove)  sudo apt remove -y "$@";;
      purge)   sudo apt purge -y "$@";;
      search)  apt search "$@";;
      upgrade) sudo apt update && sudo apt upgrade -y;;
      clean)   sudo apt autoremove -y && sudo apt clean;;
      *) echo "apt wrapper: install|remove|purge|search|upgrade|clean";;
    esac
  elif command -v pacman >/dev/null 2>&1; then
    case "$action" in
      install) sudo pacman -Syu --needed "$@";;
      remove)  sudo pacman -Rns "$@";;
      search)  pacman -Ss "$@";;
      upgrade) sudo pacman -Syu;;
      clean)   sudo pacman -Sc;;
      *) echo "pacman wrapper: install|remove|search|upgrade|clean";;
    esac
  elif command -v dnf >/dev/null 2>&1; then
    case "$action" in
      install) sudo dnf install -y "$@";;
      remove)  sudo dnf remove -y "$@";;
      search)  dnf search "$@";;
      upgrade) sudo dnf upgrade --refresh -y;;
      clean)   sudo dnf autoremove -y && sudo dnf clean packages;;
      *) echo "dnf wrapper: install|remove|search|upgrade|clean";;
    esac
  else
    echo "No supported package manager found."
    return 1
  fi
}

pm install nmap
pm search wireshark
pm clean

# apt
sudo apt update && sudo apt upgrade
sudo apt install <pkg> && sudo apt remove <pkg> && sudo apt purge <pkg>
apt search <term> && apt show <pkg>
sudo apt autoremove && sudo apt clean

# pacman
sudo pacman -Syu
sudo pacman -S <pkg> && sudo pacman -Rns <pkg>
pacman -Ss <term> && pacman -Si <pkg> && pacman -Qi <pkg>
sudo pacman -Sc

# dnf
sudo dnf upgrade --refresh
sudo dnf install <pkg> && sudo dnf remove <pkg>
dnf search <term> && dnf info <pkg> && dnf list installed
sudo dnf autoremove && sudo dnf clean packages