.\" Copyright (c) 2002 Tim J. Robbins.
.\" All rights reserved.
.\"
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.\" $FreeBSD: src/usr.bin/newgrp/newgrp.1,v 1.2 2002/05/30 13:57:35 ru Exp $
.\"
.Dd May 23, 2002
.Dt NEWGRP 1
.Os
.Sh NAME
.Nm newgrp
.Nd change to a new group
.Sh SYNOPSIS
.Nm newgrp
.Op Fl l
.Op Ar group
.Sh DESCRIPTION
The
.Nm newgrp
utility creates a new shell execution environment
with modified real and effective group IDs.
.Pp
The options are as follows:
.Bl -tag -width indent
.It Fl l
Simulate a full login.
The environment and umask are set to what would be expected
if the user actually logged in again.
.El
.Pp
If the
.Ar group
operand is present, a new shell is started
with the specified effective and real group IDs.
The user will be prompted for a password
if they are not a member of the specified group.
.Pp
Otherwise, the real, effective, and supplementary group IDs
are restored to those from the current user's password database entry.
.Sh DIAGNOSTICS
The
.Nm newgrp
utility attempts to start the shell regardless of whether group IDs
were successfully changed.
.Pp
If an error occurs and the shell cannot be started,
.Nm newgrp
exits >0.
Otherwise, the exit status of
.Nm newgrp
is the exit status of the shell.
.Sh SEE ALSO
.Xr csh 1 ,
.Xr groups 1 ,
.Xr login 1 ,
.Xr sh 1 ,
.Xr su 1 ,
.Xr umask 1 ,
.Xr group 5 ,
.Xr passwd 5 ,
.Xr environ 7
.Sh STANDARDS
The
.Nm newgrp
utility conforms to
.St -p1003.1-2001 .
.Sh HISTORY
A
.Nm newgrp
utility appeared in
.At v6 .
.Sh BUGS
Group passwords are inherently insecure,
as there is no way to stop users obtaining the encrypted passwords
from the group database.
Their use is discouraged.