opendarwin man page for newgrp

NEWGRP(1)                                                          User Commands                                                         NEWGRP(1)

NAME
       newgrp - log in to a new group

SYNOPSIS
       newgrp [-] [group]

DESCRIPTION
       The newgrp command is used to change the current group ID during a login session. If the optional - flag is given, the user's environment
       will be reinitialized as though the user had logged in, otherwise the current environment, including current working directory, remains
       unchanged.

       newgrp changes the current real group ID to the named group, or to the default group listed in /etc/passwd if no group name is given.
       newgrp also tries to add the group to the user groupset. If not root, the user will be prompted for a password if she does not have a
       password (in /etc/shadow if this user has an entry in the shadowed password file, or in /etc/passwd otherwise) and the group does, or if
       the user is not listed as a member and the group has a password. The user will be denied access if the group password is empty and the user
       is not listed as a member.

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

CONFIGURATION
       The following configuration variables in /etc/login.defs change the behavior of this tool:

       SYSLOG_SG_ENAB (boolean)
           Enable "syslog" logging of sg activity.

FILES
       /etc/passwd
           User account information.

       /etc/shadow
           Secure user account information.

       /etc/group
           Group account information.

       /etc/gshadow
           Secure group account information.

SEE ALSO
       id(1), login(1), su(1), sg(1), gpasswd(1), group(5), gshadow(5).

shadow-utils 4.5                                                    01/25/2018                                                           NEWGRP(1)