NEWGRP(1) BSD General Commands Manual NEWGRP(1)NAME
newgrp -- change to a new primary group
newgrp [-l] [group]
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
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.
/etc/group The group database
/etc/master.passwd The user database
/etc/passwd A Version 7 format password file
If a new shell is started the exit status is the exit status of the shell. Otherwise the exit status will be >0.
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'').
A newgrp command appeared in Version 6 AT&T UNIX. A newgrp command appeared in NetBSD 5.0.
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.
BSD June 6, 2007 BSD
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newgrp(1) User Commands newgrp(1)NAME
newgrp - log in to a new group
/usr/bin/newgrp [ -| -l] [group]
The newgrp command logs a user into a new group by changing a user's real and effective group ID. The user remains logged in and the cur-
rent directory is unchanged. The execution of newgrp always replaces the current shell with a new shell, even if the command terminates
with an error (unknown group).
Any variable that is not exported is reset to null or its default value. Exported variables retain their values. System variables (such as
PS1, PS2, PATH, MAIL, and HOME), are reset to default values unless they have been exported by the system or the user. For example, when a
user has a primary prompt string (PS1) other than $ (default) and has not exported PS1, the user's PS1 will be set to the default prompt
string $, even if newgrp terminates with an error. Note that the shell command export (see sh(1) and set(1)) is the method to export vari-
ables so that they retain their assigned value when invoking new shells.
With no operands and options, newgrp changes the user's group IDs (real and effective) 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.
A password is demanded if the group has a password and the user is not listed in /etc/group as being a member of that group. The only way
to create a password for a group is to use passwd(1), then cut and paste the password from /etc/shadow to /etc/group. Group passwords are
antiquated and not often used.
Equivalent to exec newgrp argument where argument represents the options and/or operand of the newgrp command.
Equivalent to exec to/bin/newgrp argument where argument represents the options and/or operand of the newgrp command.
On this man page, ksh(1) commands that are preceded by one or two * (asterisks) are treated specially in the following ways:
1. Variable assignment lists preceding the command remain in effect when the command completes.
2. I/O redirections are processed after variable assignments.
3. Errors cause a script that contains them to abort.
4. Words, following a command preceded by ** that are in the format of a variable assignment, are expanded with the same rules as a vari-
able assignment. This means that tilde substitution is performed after the = sign and word splitting and file name generation are not
The following option is supported:
-l | - Change the environment to what would be expected if the user actually logged in again as a member of the new group.
The following operands are supported:
group A group name from the group database or a non-negative numeric group ID. Specifies the group ID to which the real and
effective group IDs will be set. If group is a non-negative numeric string and exists in the group database as a group name
(see getgrnam(3C)), the numeric group ID associated with that group name will be used as the group ID.
argument sh and ksh only. Options and/or operand of the newgrp command.
See environ(5) for descriptions of the following environment variables that affect the execution of newgrp: LANG, LC_ALL, LC_CTYPE, LC_MES-
SAGES, and NLSPATH.
If newgrp succeeds in creating a new shell execution environment, whether or not the group identification was changed successfully, the
exit status will be the exit status of the shell. Otherwise, the following exit value is returned:
>0 An error occurred.
/etc/group system's group file
/etc/passwd system's password file
See attributes(5) for descriptions of the following attributes:
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|Availability |SUNWcsu |
|Interface Stability |Standard |
SEE ALSO login(1), ksh(1), set(1), sh(1), intro(3), getgrnam(3C), group(4), passwd(4), attributes(5), environ(5), standards(5)SunOS 5.10 1 Feb 1995 newgrp(1)