getent

Get list of all groups

$ getent group

$ getent group [group_name]

$ getent services

$ getent passwd 1000

$ getent hosts [host]

getent database [key...]

getent queries entries from administrative databases configured in the Name Service Switch (NSS), including local files, LDAP, NIS, and other sources. It provides a unified interface to look up users, groups, hosts, and other system information regardless of where the data is stored.
Unlike directly reading files like /etc/passwd, getent returns results from all configured NSS sources, making it essential for systems using centralized authentication (LDAP, Active Directory, etc.).
Without a key, getent lists all entries in the database. With a key, it returns only matching entries.

passwd

User account database (/etc/passwd and NSS sources)

Group database (/etc/group and NSS sources)

Hostname/IP resolution (like /etc/hosts, DNS)

Network services (/etc/services)

Network protocols (/etc/protocols)

Network names and addresses

Shadow password entries (requires root)

Mail aliases

The shadow database requires root privileges. Some databases may not support enumeration (listing all entries). Results depend on NSS configuration in /etc/nsswitch.conf.

getent has been part of the GNU C Library (glibc) since the implementation of the Name Service Switch in the early 1990s, providing a standard way to query system databases that may come from multiple sources.

id(1), groups(1), host(1), nsswitch.conf(5)