newgrp - Changes primary group identification of a shell
newgrp [-l] [group]
Obsolete Synopsis [Toc] [Back]
newgrp [-] [group]
The C shell has a built-in version of the newgrp command.
If you are using the C shell, and want to guarantee that
you are using the command described here, you must specify
the full path /usr/bin/newgrp. See the csh(1) reference
page for a description of the built-in command.
Interfaces documented on this reference page conform to
industry standards as follows:
Refer to the standards(5) reference page for more information
about industry standards and associated tags.
Changes the login environment to what would be expected if
the user logged in again. Changes the login environment
to what would be expected if the user logged in again.
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 nonnegative
numeric string and exists in the group database
as a group name, the numeric group ID associated with that
group name will be used as the group ID.
The newgrp command changes the primary group identification
of the current shell process to group. You remain
logged in and the current directory is unchanged, but calculations
of access permissions to files are performed
with respect to the primary group ID.
If you do not specify group, newgrp changes the group
identification back to that specified for the current user
in the /etc/passwd file. Only exported environment variables
retain their values after you invoke newgrp. Otherwise,
variables with a default value are reset to that
If a password is required for the specified group, and you
are not listed as a member of that group in the group
database, you are prompted to enter the correct password
for that group. If you are listed as a member of that
group, no password is requested. If no password is
required for the specified group, only users listed as
members of that group can change to that group.
[Tru64 UNIX] Only a user with superuser authority can
change the primary group of the shell process to one to
which that user does not belong.
[Tru64 UNIX] When you invoke the newgrp command from a
shell, the shell executes the command without forking a
new process. Therefore, the shell you were using when you
issued the newgrp command is unavailable after the newgrp
[Tru64 UNIX] The newgrp command is also a built-in command
for csh. There is no convenient way to enter a password
into the group database. Use of group passwords is
not encouraged because by their very nature they encourage
poor security practices.
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, a non-zero exit value is
The exit status of newgrp is generally inapplicable.
ENVIRONMENT VARIABLES [Toc] [Back]
The following environment variables affect the execution
of newgrp: Provides a default value for the internationalization
variables that are unset or null. If LANG is unset
or null, the corresponding value from the default locale
is used. If any of the internationalization variables
contain an invalid setting, the utility behaves as if none
of the variables had been defined. If set to a non-empty
string value, overrides the values of all the other internationalization
variables. Determines the locale for the
interpretation of sequences of bytes of text data as characters
(for example, single-byte as opposed to multibyte
characters in arguments). Determines the locale for the
format and contents of diagnostic messages written to
standard error. Determines the location of message catalogues
for the processing of LC_MESSAGES.
Group names declared on the system Password file
Commands: csh(1), groups(1), id(1), login(1), Bourne
shell sh(1b), POSIX shell sh(1p)
Files: group(4), passwd(4)
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