当我创建两个具有相同 UID 和 GUID 但不同主目录的用户时，我的 17.10 Ubuntu 无法启动，为什么？

Question

/etc/passwd手动编辑和文件通常不是一个好主意/etc/shadow。我建议使用系统提供的工具。除此之外，虽然您可以让一个用户与另一个用户共享相同的 GUID，但每个用户的 UID 必须是唯一的。因此，启动很可能会失败，要么是 Linux 阻止启动必要的应用程序，要么是期望 UID 唯一的应用程序失败。

两个用户共享目录的更好方法是使用组管理来实现。请参阅有关用户管理的文档或浏览询问 Ubuntu可能的指南：

但是，您只需发出以下命令即可创建用户：

sudo useradd -U -m -G <additional groups here> <user-name>

这将向您的系统添加一个用户，这将起作用。上面一行的解释来自man 8 useradd（极度缩短为仅最常用的选项，完整概述请查看手册页）：

选项

   The options which apply to the useradd command are:

   -c, --comment COMMENT
       Any text string. It is generally a short description of the login,
       and is currently used as the field for the user's full name.

   -g, --gid GROUP
       The group name or number of the user's initial login group. The
       group name must exist. A group number must refer to an already
       existing group.

       If not specified, the behavior of useradd will depend on the
       USERGROUPS_ENAB variable in /etc/login.defs. If this variable is
       set to yes (or -U/--user-group is specified on the command line), a
       group will be created for the user, with the same name as her
       loginname. If the variable is set to no (or -N/--no-user-group is
       specified on the command line), useradd will set the primary group
       of the new user to the value specified by the GROUP variable in
       /etc/default/useradd, or 100 by default.

   -G, --groups GROUP1[,GROUP2,...[,GROUPN]]]
       A list of supplementary groups which the user is also a member of.
       Each group is separated from the next by a comma, with no
       intervening whitespace. The groups are subject to the same
       restrictions as the group given with the -g option. The default is
       for the user to belong only to the initial group.

   -k, --skel SKEL_DIR
       The skeleton directory, which contains files and directories to be
       copied in the user's home directory, when the home directory is
       created by useradd.

       This option is only valid if the -m (or --create-home) option is
       specified.

       If this option is not set, the skeleton directory is defined by the
       SKEL variable in /etc/default/useradd or, by default, /etc/skel.

       If possible, the ACLs and extended attributes are copied.

   -m, --create-home
       Create the user's home directory if it does not exist. The files
       and directories contained in the skeleton directory (which can be
       defined with the -k option) will be copied to the home directory.

       By default, if this option is not specified and CREATE_HOME is not
       enabled, no home directories are created.

   -M
       Do no create the user's home directory, even if the system wide
       setting from /etc/login.defs (CREATE_HOME) is set to yes.

   -s, --shell SHELL
       The name of the user's login shell. The default is to leave this
       field blank, which causes the system to select the default login
       shell specified by the SHELL variable in /etc/default/useradd, or
       an empty string by default.

   -U, --user-group
       Create a group with the same name as the user, and add the user to
       this group.

       The default behavior (if the -g, -N, and -U options are not
       specified) is defined by the USERGROUPS_ENAB variable in
       /etc/login.defs.

因此-U将创建一个类似于用户名的用户组，其 GUID 与用户 UID 匹配。-m将在中创建用户主目录，/home/<user-name>并-G允许您指定此用户应属于的其他组。您也可以稍后添加组。Ubuntu 添加到主用户的组是adm、cdrom、sudo、dip、plugdev和。要稍后添加组lpadmin，sambashare您可以使用以下命令：

sudo usermod -aG <group-or groups> <user-name>

最后，您的用户应该有一个密码，您可以使用以下命令设置：

sudo passwd <username>

这结束了终端中的用户创建过程。

还有一个名为的组合命令adduser，可以自动执行上面提到的一些过程，有关其用法，请查看man 8 adduser。

Answer 1