id - Displays the user's system identity
id -G [-n] [user]
id -g [-nr] [user]
id -u [-nr] [user]
Interfaces documented on this reference page conform to industry standards as follows:
id: XPG4, XPG4-UNIX
Refer to the
reference page for more information
about industry standards and associated tags.
Displays all groups ids (real, effective, and supplementary)
only, as unsigned decimal numbers.
Displays only the effective group id as an unsigned decimal
Displays user and group names as strings rather than as numbers.
Displays only the real ID.
Displays only the effective user ID as an unsigned decimal
[Compaq] Displays user and all group IDs and names if the
set to the string
The user for whom information is to be written.
The id command writes to standard output a message containing the user and group IDs and corresponding names of the invoking process. If effective names and IDs do not match the real ones, the id command writes both.
If user is specified and the invoking process has sufficient privileges, the IDs and names in the message are for user rather than for the invoking process. Effective IDs are assumed identical to real IDs.
Your real user and group ids are specified in the /etc/passwd file and are your user and group ids on login. You can change your active group with the newgrp shell command (see newgrp(1)) if additional groups are specified for you in the /etc/group file. Such groups are called supplementary .
A process can also have an
user or group
id set when a set-user- or set-group-identifier program is executed. See
[Compaq] When the environment variable
is set to the string
the command syntax and output is compatible with the SVID standard. In particular,
command with no options displays the user's name
and id and the real and effective group names and ids. The
option adds any supplementary group names and ids to the display.
The following exit values are returned:
An error occurred.
To display your user and group IDs, enter: id
The following environment variables affect the execution of
[Compaq] When this environment variable
is set to the string
the command syntax and output is compatible with the SVID standard. The
option is only available in this condition.
Provides a default value for the internationalization variables
that are unset or null. If
is unset or null, the corresponding value from the default locale is used.
If any of the internationalization variables contain an invalid setting, the
utility behaves as if none of the variables had been defined.
If set to a non-empty string value, overrides the values of
all the other internationalization variables.
Determines the locale for the interpretation of sequences
of bytes of text data as characters (for example, single-byte as opposed to
multibyte characters in arguments).
Determines the locale for the format and contents of diagnostic
messages written to standard error.
Determines the location of message catalogues for the processing
Group names declared on the system.
Commands: groups(1), logname(1), newgrp(1), who(1)
Functions: getgid(2), getuid(2), setgid(2), setuid(2)
Files: group(4), passwd(4)