NEWGRP(1) General Commands Manual NEWGRP(1)
newgrp - log in to a new group
newgrp [ - ] [ group ]
newgrp changes a user's group identification. Only the group-ID is
changed; the user remains a member of all groups previously established
by setgroups (see getgroups(2V)). The user remains logged in and the
current directory is unchanged, but the group-ID of newly-created files
will be set to the new effective group-ID (see open(2V)). The user is
always given a new shell, replacing the current shell, regardless of
whether newgrp terminated successfully or due to an error condition
(such as an 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 HOME, LOGNAME, PATH, SHELL, TERM,
and USER), unless exported by the system or explicitly exported by the
user, are reset to default values. Note: the shell command export (see
sh(1)) is the method to export variables, while the C shell command
setenv (see csh(1)) implicitly exports its argument.
With no arguments, newgrp changes the group identification back to the
group specified in the user's password file entry.
If the first argument to newgrp is a `-', the environment is changed to
what would be expected if the user actually logged in again.
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 is not listed in
/etc/group as being a member of that group.
/etc/group system group file
/etc/passwd system password file
csh(1), login(1), sh(1), su(1V), open(2V), getgroups(2V), init-
groups(3), environ(5V), group(5), passwd(5)
For consistency with login naming rules (which do not allow 8-bit file
names), group identifications cannot contain 8-bit characters. See
login(1) for explanations about why login is not 8-bit clean.
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
16 November 1987 NEWGRP(1)