lid.libuser

List primary and secondary groups of a specific user

$ sudo lid [username]

$ sudo lid --group [group_name]

lid [OPTION]... [name]

lid displays information about group membership on Linux systems. By default, it shows all groups containing a specified user (or the invoking user if no name is given). With the -g option, it reverses this behavior to show all users within a specified group.
Part of the libuser library tools, lid reads from the system's user and group databases. It requires root privileges to query membership information for other users or groups.

-g, --group

List users belonging to a group instead of groups containing a user

Prompt for all configuration questions when accessing the user database

Display only names without corresponding numeric IDs

Requires root privileges (sudo) to query information about users or groups other than the invoking user. The command depends on the libuser library configuration for database access.

The lid command is part of the libuser library project, developed in the early 2000s to provide a common interface for user and group account manipulation across different Linux distributions.

groups(1), id(1), getent(1), usermod(8)