Linux and Unix newgrp command

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About newgrp
Syntax
Examples
Related commands
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About newgrp

The newgrp command allows a user to log in to a new group.

Syntax

newgrp [-] [group]

Description

The newgrp command is used to change the current group ID (GID) during a login session. If a hyphen ("-") is included as an argument, then the user's environment is initialized as though he or she had just logged in; otherwise, the current working environment remains unchanged. newgrp changes the current real group ID to the specified group, or, if no group is specified, to the default group listed in the file /etc/passwd. newgrp also tries to add the group to the user groupset.

If the user is root, he or she will not be prompted for a password.

If the user is not root, he or she will be prompted for a group password if:

  • the user does not have a password, but the group does, or if
  • the user is not listed as a group member, and the group has a password.

If there is no group password set, and the user is not listed as a member of the group, the user will be denied access.

If there is an entry for the group in the shadowed group password file, /etc/gshadow, then the list of members and the password for this group will be taken from this file. Otherwise, the group entry in /etc/group is used.

Files

newgrp makes use of the following files:

/etc/passwd User account information.
/etc/shadow Secure user account information.
/etc/group Group account information.
/etc/gshadow Secure group account information.

Examples

newgrp developers

Attemts to log in to the group developers.

newgrp - developers

Attemps to log in to the group developers, and, if successful, re-initializes the user environment.

Related commands

gpasswd
ksh
login
set
sh