Linux -- newgrp

NEWGRP(1)                          用户命令                          NEWGRP(1)

名称
       newgrp - 登录到一个新组

大纲
       newgrp [-] [group]

描述
       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.

配置文件
       在 /etc/login.defs 中有如下配置变量，可以用来更改此工具的行为：

       SYSLOG_SG_ENAB (boolean)
           允许“syslog”记录 sg 的活动。

文件
       /etc/passwd
           用户账户信息。

       /etc/shadow
       /etc/group
           组账户信息。

       /etc/gshadow
           安全组账户信息。

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

shadow-utils 4.1.5.1              2014-02-17                         NEWGRP(1)

Linux -- newgrp

原文：http://www.cnblogs.com/IceSword-syy/p/3953438.html