id(1) [osx man page]

ID(1)							    BSD General Commands Manual 						     ID(1)

NAME

     id -- return user identity

SYNOPSIS

     id [user]
     id -A
     id -G [-n] [user]
     id -M
     id -P [user]
     id -g [-nr] [user]
     id -p [user]
     id -u [-nr] [user]

DESCRIPTION

     The id utility displays the user and group names and numeric IDs, of the calling process, to the standard output.	If the real and effective
     IDs are different, both are displayed, otherwise only the real ID is displayed.

     If a user (login name or user ID) is specified, the user and group IDs of that user are displayed.  In this case, the real and effective IDs
     are assumed to be the same.

     The options are as follows:

     -A      Display the process audit user ID and other process audit properties, which requires privilege.

     -G      Display the different group IDs (effective, real and supplementary) as white-space separated numbers, in no particular order.

     -M      Display the MAC label of the current process.

     -P      Display the id as a password file entry.

     -a      Ignored for compatibility with other id implementations.

     -g      Display the effective group ID as a number.

     -n      Display the name of the user or group ID for the -G, -g and -u options instead of the number.  If any of the ID numbers cannot be
	     mapped into names, the number will be displayed as usual.

     -p      Make the output human-readable.  If the user name returned by getlogin(2) is different from the login name referenced by the user ID,
	     the name returned by getlogin(2) is displayed, preceded by the keyword ``login''.	The user ID as a name is displayed, preceded by
	     the keyword ``uid''.  If the effective user ID is different from the real user ID, the real user ID is displayed as a name, preceded
	     by the keyword ``euid''.  If the effective group ID is different from the real group ID, the real group ID is displayed as a name,
	     preceded by the keyword ``rgid''.	The list of groups to which the user belongs is then displayed as names, preceded by the keyword
	     ``groups''.  Each display is on a separate line.

     -r      Display the real ID for the -g and -u options instead of the effective ID.

     -u      Display the effective user ID as a number.

EXIT STATUS

     The id utility exits 0 on success, and >0 if an error occurs.

SEE ALSO

     who(1)

STANDARDS

     The id function is expected to conform to IEEE Std 1003.2 (``POSIX.2'').

HISTORY

     The historic groups(1) command is equivalent to ``id -Gn [user]''.

     The historic whoami(1) command is equivalent to ``id -un''.

     The id command appeared in 4.4BSD.

BSD
								September 26, 2006							       BSD

Check Out this Related Man Page

NEWGRP(1)						    BSD General Commands Manual 						 NEWGRP(1)

NAME

     newgrp -- change to a new primary group

SYNOPSIS

     newgrp [-l] [group]

DESCRIPTION

     The newgrp command changes a user to a new primary group (real and effective group ID) by starting a new shell.  The user remains logged in
     and the current directory and file creation mask remain unchanged.  The user is always given a new shell even if the primary group change
     fails.

     The newgrp command accepts the following options:

     -l      The environment is changed to what would be expected if the user actually logged in again.  This simulates a full login.

     The group is a group name or non-negative numeric group ID from the group database.  The real and effective group IDs are set to group or the
     group ID associated with the group name.

     If group is not specified, newgrp restores the user's real and effective group IDs to the user's primary group specified in the password
     database.	The user's supplementary group IDs are restored to the set specified for the user in the group database.

     If the user is not a member of the specified group, and the group requires a password, the user will be prompted for the group password.

FILES

     /etc/group 	 The group database
     /etc/master.passwd  The user database
     /etc/passwd	 A Version 7 format password file

EXIT STATUS

     If a new shell is started the exit status is the exit status of the shell.  Otherwise the exit status will be >0.

SEE ALSO

     csh(1), groups(1), login(1), sh(1), su(1), umask(2), group(5), passwd(5), environ(7)

STANDARDS

     The newgrp command conforms to IEEE Std 1003.1-2001 (``POSIX.1'').

HISTORY

     A newgrp command appeared in Version 6 AT&T UNIX.	A newgrp command appeared in NetBSD 5.0.

BUGS

     There is no convenient way to enter a password into /etc/group.  The use of group passwords is strongly discouraged since they are inherently
     insecure.	It is not possible to stop users from obtaining the encrypted password from the group database.

BSD
								   June 6, 2007 							       BSD

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id(1) [osx man page]

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