lp

What this account is

Names both a user and a group: UID 7 in Debian, UID 4 in Alpine, and group 7 in both. Two roles meet at this name. It gates printer hardware, since udev on Debian assigns the group to parallel ports and ppdev, kernel lp* printer devices, IrDA printers, and USB devices whose interface class identifies them as printers; membership carries direct access to the device, which a print service normally holds on users' behalf rather than each user holding it individually. It is also the identity CUPS selects for itself: when built on a system whose passwd file already has an lp account, CUPS takes lp as its default user and group, the identity its configuration names for filters, backends and helper programs. Administration is deliberately kept apart from it. CUPS picks its administrative group from a separate list headed by lpadmin, and refuses to build if the two resolve to the same group. Neither distribution makes the account interactive: Debian gives it /usr/sbin/nologin and Alpine /sbin/nologin, and both give it the older lpd spool, /var/spool/lpd, as its home directory.

Source: udev 249.11, 50-udev-default.rules; CUPS (OpenPrinting), config-scripts/cups-defaults.m4 and conf/cups-files.conf.in; base-passwd 3.6.8 (passwd); alpine-baselayout passwd, aports. Read 2026-08-08.

Sources