id - Displays the user's system identity
id -G [-n] [user]
id -g [-nr] [user]
id -u [-nr] [user]
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-G Displays all groups ids (real, effective, and supplementary) only, as
unsigned decimal numbers.
-g Displays only the effective group id as an unsigned decimal number.
-n Displays user and group names as strings rather than as numbers.
-r Displays only the real ID.
-u Displays only the effective user ID as an unsigned decimal number.
-a [Tru64 UNIX] Displays user and all group IDs and names if the environ-
ment variable CMD_ENV is set to the string svr4.
The user for whom information is to be written.
If this parameter is omitted, the user and group names associated with
the invoking process are used.
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 effective user or group id set when a set-user-
or set-group-identifier program is executed. See setuid(2), setgid(2).
[Tru64 UNIX] When the environment variable CMD_ENV is set to the string
svr4, the command syntax and output is compatible with the SVID standard.
In particular, the id command with no options displays the user's name and
id and the real and effective group names and ids. The -a option adds any
supplementary group names and ids to the display.
The following exit values are returned:
0 Successful completion.
>>0 An error occurred.
1. To display your user and group IDs, enter:
Information is displayed similar to:
In the case where a user belongs to a supplementary group, information
is displayed similar to:
uid=200(thomas) gid=1(staff) groups=0(system)
However, if the environment variable CMD_ENV is set to the string
svr4, the command id with no options does not display any supplemen-
tary groups and results in a display similar to:
2. To display supplementary groups with CMD_ENV set to svr4, use the com-
mand id -a. The display is then similar to:
uid=200(thomas) gid=1(staff) groups=1(users),0(system)
The following environment variables affect the execution of id:
[Tru64 UNIX] When this environment variable CMD_ENV is set to the
string svr4, the command syntax and output is compatible with the SVID
standard. The -a option is only available in this condition.
Provides a default value for the internationalization variables that
are unset or null. If LANG 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 multi-
byte characters in arguments).
Determines the locale for the format and contents of diagnostic mes-
sages written to standard error.
Determines the location of message catalogues for the processing of
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)