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[root@localhost ~]# groupadd test

[root@localhost ~]# useradd -g test test

[root@localhost ~]# passwd test

更改用户 test 的密码 。

新的 密码：

无效的密码： 过于简单化/系统化

无效的密码： 过于简单

重新输入新的 密码：

passwd： 所有的身份验证令牌已经成功更新。

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[root@localhost ~]# chmod -v u+w /etc/sudoers 

mode of '/etc/sudoers' changed from 0440 (r--r-----) to 0640 (rw-r-----)

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[root@localhost ~]# vim /etc/sudoers

## Sudoers allows particular users to run various commands as

## the root user, without needing the root password.

##

## Examples are provided at the bottom of the file for collections

## of related commands, which can then be delegated out to particular

## users or groups.

##

## This file must be edited with the 'visudo' command.

## Host Aliases

## Groups of machines. You may prefer to use hostnames (perhaps using

## wildcards for entire domains) or IP addresses instead.

# Host_Alias     FILESERVERS = fs1, fs2

# Host_Alias     MAILSERVERS = smtp, smtp2

## User Aliases

## These aren't often necessary, as you can use regular groups

## (ie, from files, LDAP, NIS, etc) in this file - just use %groupname

## rather than USERALIAS

# User_Alias ADMINS = jsmith, mikem

## Command Aliases

## These are groups of related commands...

## Networking

# Cmnd_Alias NETWORKING = /sbin/route, /sbin/ifconfig, /bin/ping, /sbin/dhclient, /usr/bin/net, /sbin/iptables, /usr/bin/rfcomm, /usr/bin/wvdial, /sbin/iwconfig, /sbin/mii-tool

## Installation and management of software

# Cmnd_Alias SOFTWARE = /bin/rpm, /usr/bin/up2date, /usr/bin/yum

## Services

# Cmnd_Alias SERVICES = /sbin/service, /sbin/chkconfig, /usr/bin/systemctl start, /usr/bin/systemctl stop, /usr/bin/systemctl reload, /usr/bin/systemctl restart, /usr/bin/systemctl status, /usr/bin/systemctl enable, /usr/bin/systemctl disable

## Updating the locate database

# Cmnd_Alias LOCATE = /usr/bin/updatedb

## Storage

# Cmnd_Alias STORAGE = /sbin/fdisk, /sbin/sfdisk, /sbin/parted, /sbin/partprobe, /bin/mount, /bin/umount

## Delegating permissions

# Cmnd_Alias DELEGATING = /usr/sbin/visudo, /bin/chown, /bin/chmod, /bin/chgrp

## Processes

# Cmnd_Alias PROCESSES = /bin/nice, /bin/kill, /usr/bin/kill, /usr/bin/killall

## Drivers

# Cmnd_Alias DRIVERS = /sbin/modprobe

# Defaults specification

#

# Refuse to run if unable to disable echo on the tty.

#

Defaults   !visiblepw

#

# Preserving HOME has security implications since many programs

# use it when searching for configuration files. Note that HOME

# is already set when the the env_reset option is enabled, so

# this option is only effective for configurations where either

# env_reset is disabled or HOME is present in the env_keep list.

#

Defaults    always_set_home

Defaults    match_group_by_gid

# Prior to version 1.8.15, groups listed in sudoers that were not

# found in the system group database were passed to the group

# plugin, if any. Starting with 1.8.15, only groups of the form

# %:group are resolved via the group plugin by default.

# We enable always_query_group_plugin to restore old behavior.

# Disable this option for new behavior.

Defaults    always_query_group_plugin

Defaults    env_reset

Defaults    env_keep =  "COLORS DISPLAY HOSTNAME HISTSIZE KDEDIR LS_COLORS"

Defaults    env_keep += "MAIL PS1 PS2 QTDIR USERNAME LANG LC_ADDRESS LC_CTYPE"

Defaults    env_keep += "LC_COLLATE LC_IDENTIFICATION LC_MEASUREMENT LC_MESSAGES"

Defaults    env_keep += "LC_MONETARY LC_NAME LC_NUMERIC LC_PAPER LC_TELEPHONE"

Defaults    env_keep += "LC_TIME LC_ALL LANGUAGE LINGUAS _XKB_CHARSET XAUTHORITY"

#

# Adding HOME to env_keep may enable a user to run unrestricted

# commands via sudo.

#

# Defaults   env_keep += "HOME"

Defaults    secure_path = /sbin:/bin:/usr/sbin:/usr/bin

## Next comes the main part: which users can run what software on

## which machines (the sudoers file can be shared between multiple

## systems).

## Syntax:

##

##      user    MACHINE=COMMANDS

##

## The COMMANDS section may have other options added to it.

##

## Allow root to run any commands anywhere

root    ALL=(ALL)       ALL

## Allows members of the 'sys' group to run networking, software,

## service management apps and more.

# %sys ALL = NETWORKING, SOFTWARE, SERVICES, STORAGE, DELEGATING, PROCESSES, LOCATE, DRIVERS

## Allows people in group wheel to run all commands

%wheel  ALL=(ALL)       ALL

## Same thing without a password

# %wheel ALL=(ALL)      NOPASSWD: ALL

## Allows members of the users group to mount and unmount the

## cdrom as root

# %users  ALL=/sbin/mount /mnt/cdrom, /sbin/umount /mnt/cdrom

## Allows members of the users group to shutdown this system

# %users  localhost=/sbin/shutdown -h now

## Read drop-in files from /etc/sudoers.d (the # here does not mean a comment)

#includedir /etc/sudoers.d

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root    ALL=(ALL)       ALL

test    ALL=(ALL)       ALL

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test ALL=(ALL)       NOPASSWD:ALL

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[root@localhost ~]# chmod -v u-w /etc/sudoers  

mode of "/etc/sudoers" changed from 0640 (rw-r-----) to 0440 (r--r-----)

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[root@localhost ~]# ll /etc/passwd

-rw-r--r--. 1 root root 2347 4f  16 21:00 /etc/passwd

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[root@localhost ~]# ll /bin/su

-rwsrwxrwx. 1 root root 32128 8f   9 2019 /bin/su