.\" Copyright (c) 2002 Tim J. Robbins.
.\" All rights reserved.
.\"
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.\" modification, are permitted provided that the following conditions
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.\" $FreeBSD$
.\"
.Dd February 8, 2013
.Dt NEWGRP 1
.Os
.Sh NAME
.Nm newgrp
.Nd change to a new group
.Sh SYNOPSIS
.Nm
.Op Fl l
.Op Ar group
.Sh DESCRIPTION
The
.Nm
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 EXIT STATUS
The
.Nm
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
exits >0.
Otherwise, the exit status of
.Nm
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
utility conforms to
.St -p1003.1-2001 .
.Sh HISTORY
A
.Nm
utility appeared in
.At v6 .
.Sh BUGS
For security reasons, the
.Nm
utility is normally installed without the setuid bit.
To enable it, run the following command:
.Bd -literal -offset indent
chmod u+s /usr/bin/newgrp
.Ed
.Pp
Group passwords are inherently insecure as there is no way to stop
users obtaining the password hash from the group database.
Their use is discouraged.
Instead, users should simply be added to the necessary groups.