NEWGRP(1M) (Essential Utilities) NEWGRP(1M)
NAME
newgrp - log in to a new group
SYNOPSIS
newgrp [-] [ group ]
DESCRIPTION
newgrp changes a user's group identification. The user
remains logged in and the current directory is unchanged,
but calculations of access permissions to files are
performed with respect to the new real and effective group
IDs. The user is always given a new shell, replacing the
current shell, by newgrp, regardless of whether it
terminated successfully or due to an error condition (i.e.,
unknown group).
Exported variables retain their values after invoking
newgrp; however, all unexported variables are either reset
to their default value or set to null. System variables
(such as PS1, PS2, PATH, MAIL, and HOME), unless exported by
the system or explicitly exported by the user, are reset to
default values. For example, a user has a primary prompt
string (PS1) other than $ (default) and has not exported
PS1. After an invocation of newgrp , successful or not,
their PS1 will now be set to the default prompt string $.
Note that the shell command export (see sh(1)) is the method
to export variables so that they retain their assigned value
when invoking new shells.
With no arguments, newgrp changes the group identification
back to the group specified in the user's password file
entry. This is a way to exit the effect of an earlier
newgrp command.
If the first argument to newgrp is a -, the environment is
changed to what would be expected if the user actually
logged in again as a member of the new group.
A password is demanded if the group has a password and the
user does not, or if the group has a password and the user
Page 1 May 1989
NEWGRP(1M) (Essential Utilities) NEWGRP(1M)
is not listed in /etc/group as being a member of that group.
UniSoft UNIX System V uses POSIX multiple groups whereby a
user simultaneously maintains membership in all the groups
the user is a member of. However, since the group id of
files created in a multiple group environment is set to the
current effective group id, newgrp provides a mechanism to
change this value, thus changing the group id of newly
created files.
FILES
/etc/group system's group file
/etc/passwd system's password file
SEE ALSO
login(1), sh(1) in the User's Reference Manual.
group(4), passwd(4), environ(5) in the Programmer's
Reference Manual.
BUGS
There is no convenient way to enter a password into
/etc/group. Use of group passwords is not encouraged,
because, by their very nature, they encourage poor security
practices. Group passwords may disappear in the future.
Page 2 May 1989