paclock

Lock the database

$ sudo paclock

$ paclock --print

$ sudo paclock --unlock

$ paclock --help

$ paclock --version

paclock [-fhuq] [-d directory]

-d, --directory <dir>
    Use alternate directory instead of /var/lib/pacman.

-f, --force
    Forcibly remove all lock files in directory.

-h, --help
    Print usage help and exit.

-q, --quiet
    Suppress all non-error output.

-u, --unlock
    Remove existing lock file if present.

Paclock is a utility bundled with the pacman package manager on Arch Linux and derivatives. It manages exclusive locks on the pacman database directory (default: /var/lib/pacman) to avoid simultaneous modifications that could corrupt the package database.

By default, paclock acquires and holds an exclusive lock on db.lck. If locked by another process, it waits indefinitely until released or interrupted (e.g., Ctrl+C). This ensures safe concurrency during package installations, updates, or removals.

Pacman invokes paclock automatically, but it can be used standalone in scripts to check or enforce locks before operations. Options allow unlocking stale locks or forcing removal, though the latter risks data loss if processes are active.

Reliant on filesystem locking (e.g., fcntl or flock), it works on most Linux filesystems but may behave differently on network mounts.

-f can corrupt database if pacman is running; verify with ps aux | grep pacman. Arch Linux-specific; ineffective on unsupported filesystems.

Acquires/holds lock indefinitely; waits if locked; Ctrl+C to release.

paclock -q (quiet lock).
paclock -u (unlock).
paclock -f (force clear locks).

Developed by Arch Linux team as part of pacman since ~2006 (pacman 3.x era) for safe concurrency; maintained in pacman-contrib or core pacman package.

pacman(8)