id - Displays the user's system identity
id -G [-n] [user]
id -g [-nr] [user]
id -u [-nr] [user]
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Displays all groups ids (real, effective, and supplementary)
only, as unsigned decimal numbers. Displays only
the effective group id as an unsigned decimal number.
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 number. [Tru64
UNIX] Displays user and all group IDs and names if the
environment 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
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
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).
SVID Conformance [Toc] [Back]
[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: Successful completion.
An error occurred.
To display your user and group IDs, enter: id
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 supplementary groups and
results in a display similar to: uid=200(thomas)
gid=1(staff) To display supplementary groups with
CMD_ENV set to svr4, use the command id -a. The
display is then similar to: uid=200(thomas)
ENVIRONMENT VARIABLES [Toc] [Back]
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 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. Password file.
Commands: groups(1), logname(1), newgrp(1), who(1)
Functions: getgid(2), getuid(2), setgid(2), setuid(2)
Files: group(4), passwd(4)
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