1 .\" Copyright (c) 2002 Tim J. Robbins.
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30 .Nd change to a new group
38 utility creates a new shell execution environment with modified
39 real and effective group IDs.
41 The options are as follows:
42 .Bl -tag -width indent
44 Simulate a full login.
45 The environment and umask are set to what would be expected if the user
46 actually logged in again.
51 operand is present, a new shell is started with the specified effective
53 The user will be prompted for a password if they are not a member of the
56 Otherwise, the real, effective and supplementary group IDs are restored to
57 those from the current user's password database entry.
61 utility attempts to start the shell regardless of whether group IDs
62 were successfully changed.
64 If an error occurs and the shell cannot be started,
67 Otherwise, the exit status of
69 is the exit status of the shell.
91 For security reasons, the
93 utility is normally installed without the setuid bit.
94 To enable it, run the following command:
95 .Bd -literal -offset indent
96 chmod u+s /usr/bin/newgrp
99 Group passwords are inherently insecure as there is no way to stop
100 users obtaining the password hash from the group database.
101 Their use is discouraged.
102 Instead, users should simply be added to the necessary groups.