NEWGRP(1) User Commands NEWGRP(1)

NAME

newgrp - log in to a new group

SYNOPSIS

Command

/usr/bin/newgrp [-| -l] [group]


sh Built-in
newgrp [argument]


ksh Built-in
*newgrp [argument]


ksh93 Built-in
+newgrp [argument]

DESCRIPTION

Command

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
current 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 is 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 variables 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.

sh Built-in
Equivalent to exec newgrp argument where argument represents the
options and/or operand of the newgrp command.

ksh Built-in
Equivalent to exec /usr/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 variable assignment. This means that
tilde substitution is performed after the = sign and word
splitting and file name generation are not performed.

ksh93 Built-in
Equivalent to exec /usr/bin/newgrp argument where argument represents
the options and/or operand of the newgrp command.


On this man page, ksh93(1) commands that are preceded by one or two +
(plus signs) 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. They are not valid function names.

5. Words, following a command preceded by ++ that are in the
format of a variable assignment, are expanded with the
same rules as a variable assignment. This means that
tilde substitution is performed after the = sign and field
splitting and file name generation are not performed.

OPTIONS

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.

OPERANDS

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 is 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 is used as the group ID.


argument
sh and ksh only. Options and/or operand of the newgrp
command.

ENVIRONMENT VARIABLES

See environ(7) for descriptions of the following environment
variables that affect the execution of newgrp: LANG, LC_ALL,
LC_CTYPE, LC_MESSAGES, and NLSPATH.

EXIT STATUS

If newgrp succeeds in creating a new shell execution environment,
whether or not the group identification was changed successfully, the
exit status is the exit status of the shell. Otherwise, the following
exit value is returned:

>0
An error occurred.

FILES

/etc/group
System group file


/etc/passwd
System password file

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:

/usr/bin/newgrp, ksh, sh

+--------------------+-------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-------------------+
|Interface Stability | Committed |
+--------------------+-------------------+
|Standard | See standards(7). |
+--------------------+-------------------+

ksh93

+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Uncommitted |
+--------------------+-----------------+

SEE ALSO

ksh(1), ksh93(1), login(1), set(1), sh(1), Intro(3), getgrnam(3C),
group(5), passwd(5), attributes(7), environ(7), standards(7)

August 13, 2023 NEWGRP(1)