LinuxCommandLibrary

getent

get entries from Name Service Switch libraries

TLDR

Get list of all groups

$ getent group
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See the members of a group
$ getent group [group_name]
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Get list of all services
$ getent services
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Find a username by UID
$ getent passwd 1000
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Perform a reverse DNS lookup
$ getent hosts [host]
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SYNOPSIS

getent [option]... database key...

DESCRIPTION

The getent command displays entries from databases supported by the Name Service Switch libraries, which are configured in /etc/nsswitch.conf. If one or more key arguments are provided, then only the entries that match the supplied keys will be displayed. Otherwise, if no key is provided, all entries will be displayed (unless the database does not support enumeration).

The database may be any of those supported by the GNU C Library, listed below:

ahosts

When no key is provided, use sethostent(3), gethostent(3), and endhostent(3) to enumerate the hosts database. This is identical to using hosts. When one or more key arguments are provided, pass each key in succession to getaddrinfo(3) with the address family AF_UNSPEC, enumerating each socket address structure returned.

ahostsv4

Same as ahosts, but use the address family AF_INET.

ahostsv6

Same as ahosts, but use the address family AF_INET6. The call to getaddrinfo(3) in this case includes the AI_V4MAPPED flag.

aliases

When no key is provided, use setaliasent(3), getaliasent(3), and endaliasent(3) to enumerate the aliases database. When one or more key arguments are provided, pass each key in succession to getaliasbyname(3) and display the result.

ethers

When one or more key arguments are provided, pass each key in succession to ether_aton(3) and ether_hostton(3) until a result is obtained, and display the result. Enumeration is not supported on ethers, so a key must be provided.

group

When no key is provided, use setgrent(3), getgrent(3), and endgrent(3) to enumerate the group database. When one or more key arguments are provided, pass each numeric key to getgrgid(3) and each nonnumeric key to getgrnam(3) and display the result.

gshadow

When no key is provided, use setsgent(3), getsgent(3), and endsgent(3) to enumerate the gshadow database. When one or more key arguments are provided, pass each key in succession to getsgnam(3) and display the result.

hosts

When no key is provided, use sethostent(3), gethostent(3), and endhostent(3) to enumerate the hosts database. When one or more key arguments are provided, pass each key to gethostbyaddr(3) or gethostbyname2(3), depending on whether a call to inet_pton(3) indicates that the key is an IPv6 or IPv4 address or not, and display the result.

initgroups

When one or more key arguments are provided, pass each key in succession to getgrouplist(3) and display the result. Enumeration is not supported on initgroups, so a key must be provided.

netgroup

When one key is provided, pass the key to setnetgrent(3) and, using getnetgrent(3) display the resulting string triple (hostname, username, domainname). Alternatively, three keys may be provided, which are interpreted as the hostname, username, and domainname to match to a netgroup name via innetgr(3). Enumeration is not supported on netgroup, so either one or three keys must be provided.

networks

When no key is provided, use setnetent(3), getnetent(3), and endnetent(3) to enumerate the networks database. When one or more key arguments are provided, pass each numeric key to getnetbyaddr(3) and each nonnumeric key to getnetbyname(3) and display the result.

passwd

When no key is provided, use setpwent(3), getpwent(3), and endpwent(3) to enumerate the passwd database. When one or more key arguments are provided, pass each numeric key to getpwuid(3) and each nonnumeric key to getpwnam(3) and display the result.

protocols

When no key is provided, use setprotoent(3), getprotoent(3), and endprotoent(3) to enumerate the protocols database. When one or more key arguments are provided, pass each numeric key to getprotobynumber(3) and each nonnumeric key to getprotobyname(3) and display the result.

rpc

When no key is provided, use setrpcent(3), getrpcent(3), and endrpcent(3) to enumerate the rpc database. When one or more key arguments are provided, pass each numeric key to getrpcbynumber(3) and each nonnumeric key to getrpcbyname(3) and display the result.

services

When no key is provided, use setservent(3), getservent(3), and endservent(3) to enumerate the services database. When one or more key arguments are provided, pass each numeric key to getservbynumber(3) and each nonnumeric key to getservbyname(3) and display the result.

shadow

When no key is provided, use setspent(3), getspent(3), and endspent(3) to enumerate the shadow database. When one or more key arguments are provided, pass each key in succession to getspnam(3) and display the result.

OPTIONS

-s service, --service service

Override all databases with the specified service. (Since glibc 2.2.5.)

-s database:service, --service database:service

Override only specified databases with the specified service. The option may be used multiple times, but only the last service for each database will be used. (Since glibc 2.4.)

-i, --no-idn

Disables IDN encoding in lookups for ahosts/getaddrinfo(3) (Since glibc-2.13.)

-?, --help

Print a usage summary and exit.

--usage

Print a short usage summary and exit.

-V, --version

Print the version number, license, and disclaimer of warranty for getent.

EXIT STATUS

One of the following exit values can be returned by getent:

0

Command completed successfully.

1

Missing arguments, or database unknown.

2

One or more supplied key could not be found in the database.

3

Enumeration not supported on this database.

SEE ALSO

nsswitch.conf(5)

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