June 6, 2007 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.

### 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.

### FILES

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

### 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 NetBSD5.0.

### 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.