Linux添加用户组和添加用户

1.用户组

• 添加组：groupadd 组名

  [root@Server-n93yom ~]# groupadd dev
  [root@Server-n93yom ~]# cat /etc/group | grep dev
  dev:x:10011:
  [root@Server-n93yom ~]#

• 删除组：groupdel 组名

  [root@Server-n93yom ~]# groupdel dev
  [root@Server-n93yom ~]# cat /etc/group | grep dev
  [root@Server-n93yom ~]#

• 查询组：cat /etc/group 或者使用管道来精确查询 cat /etc/group | grep dev

  [root@Server-n93yom ~]# cat /etc/group
  root:x:0:
  bin:x:1:
  daemon:x:2:
  sys:x:3:
  adm:x:4:
  tty:x:5:
  disk:x:6:
  lp:x:7:
  mem:x:8:
  kmem:x:9:
  wheel:x:10:
  cdrom:x:11:
  mail:x:12:postfix
  man:x:15:
  dialout:x:18:
  floppy:x:19:
  games:x:20:
  tape:x:30:
  video:x:39:
  ftp:x:50:
  lock:x:54:
  audio:x:63:
  nobody:x:99:
  users:x:100:
  utmp:x:22:
  utempter:x:35:
  ssh_keys:x:999:
  input:x:998:
  systemd-journal:x:190:
  systemd-bus-proxy:x:997:
  systemd-network:x:192:
  dbus:x:81:
  polkitd:x:996:
  tss:x:59:
  dip:x:40:
  postdrop:x:90:
  postfix:x:89:
  sshd:x:74:
  check:x:1000:check
  cfyuser:x:10000:
  consul:x:10002:
  rabbitmq:x:10003:
  mysql:x:10009:
  prometheus:x:10004:
  grafana:x:10005:
  logstash:x:10006:
  nginx:x:995:
  tomcat:x:10008:
  guanbin:x:10010:
  dev:x:10011:

        /etc 目录是专门用来保存 系统配置信息 的目录

        group 是保存组信息的文件

2.用户

•  添加用户：useradd -m -g 组 新建用户名            注意：-m 自动建立用户家目录； -g 指定用户所在的组，否则会建立一个和用户名同名的组 

  [root@Server-n93yom ~]# useradd -m -g dev test1
  [root@Server-n93yom ~]#

  dev为用户组，test1为用户名

• 查询用户：在/etc/passwd文件下存储的是用户的list

  [root@Server-n93yom ~]# cat /etc/passwd
  root:x:0:0:root:/root:/bin/bash
  bin:x:1:1:bin:/bin:/sbin/nologin
  daemon:x:2:2:daemon:/sbin:/sbin/nologin
  adm:x:3:4:adm:/var/adm:/sbin/nologin
  lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
  sync:x:5:0:sync:/sbin:/bin/sync
  shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
  halt:x:7:0:halt:/sbin:/sbin/halt
  mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
  operator:x:11:0:operator:/root:/sbin/nologin
  games:x:12:100:games:/usr/games:/sbin/nologin
  ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin
  nobody:x:99:99:Nobody:/:/sbin/nologin
  systemd-bus-proxy:x:999:997:systemd Bus Proxy:/:/sbin/nologin
  systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin
  dbus:x:81:81:System message bus:/:/sbin/nologin
  polkitd:x:998:996:User for polkitd:/:/sbin/nologin
  tss:x:59:59:Account used by the trousers package to sandbox the tcsd daemon:/dev/null:/sbin/nologin
  postfix:x:89:89::/var/spool/postfix:/sbin/nologin
  sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
  check:x:1000:1000:check:/home/check:/bin/bash
  cfyuser:x:10000:10000::/home/cfyuser:/bin/bash
  consul:x:10002:10002::/opt/cloudchef/consul:/sbin/nologin
  rabbitmq:x:10003:10003::/etc/rabbitmq:/sbin/nologin
  mysql:x:10009:10009::/home/mysql:/bin/bash
  prometheus:x:10004:10004::/home/prometheus:/sbin/nologin
  grafana:x:10005:10005::/home/grafana:/bin/bash
  logstash:x:10006:10006::/home/logstash:/bin/bash
  nginx:x:997:995:nginx user:/var/cache/nginx:/sbin/nologin
  tomcat:x:10008:10008::/opt/cloudchef/tomcat:/sbin/nologin
  test:x:10010:10010::/home/test:/bin/bash
  test1:x:10011:10011::/home/test1:/bin/bash

• 只查找test1用户

  [root@Server-n93yom ~]# id test1
  uid=10011(test1) gid=10011(dev) groups=10011(dev)
  [root@Server-n93yom ~]#

  uid为用户id,  gid为组id

• 修改和创建密码 passwd 用户名    如果不加用户名则默认修改当前登录者的密码

  [root@Server-n93yom ~]# passwd test1
  Changing password for user test1.
  New password:
  BAD PASSWORD: The password is shorter than 8 characters
  Retype new password:
  passwd: all authentication tokens updated successfully.
  [root@Server-n93yom ~]#

  设置好密码后，使用此账号和密码登录

  ➜  ~ ssh test1@192.168.85.163
  test1@192.168.85.163's password:
  Last failed login: Mon Jul 22 17:00:05 CST 2019 from 192.168.1.53 on ssh:notty
  There were 3 failed login attempts since the last successful login.
  [test1@Server-n93yom ~]$

• 设置用户不能修改密码

  [root@Server-n93yom ~]# passwd -l test1     //在root下，禁止test1用户修改密码的权限
  Locking password for user test1.            //锁住test1不能修改密码
  passwd: Success
  [root@Server-n93yom ~]# su test1            //切换用户
  [test1@Server-n93yom root]$ passwd          //修改密码
  Changing password for user test1.
  Changing password for test1.
  (current) UNIX password:
  passwd: Authentication token manipulation error  //没用权限修改密码
  [test1@Server-n93yom root]$

• 清除密码

  [root@Server-n93yom ~]# passwd -d test1    //删除test1的密码
  Removing password for user test1.
  passwd: Success
  [root@Server-n93yom ~]# passwd -S test1     //查看test1的密码
  test1 NP 2019-07-22 0 99999 7 -1 (Empty password.)   //密码为空
  [root@Server-n93yom ~]#

• passwd 帮助命令

  [root@Server-n93yom ~]# passwd --help
  Usage: passwd [OPTION...] <accountName>
    -k, --keep-tokens       keep non-expired authentication tokens
    -d, --delete            delete the password for the named account (root only)
    -l, --lock              lock the password for the named account (root only)
    -u, --unlock            unlock the password for the named account (root only)
    -e, --expire            expire the password for the named account (root only)
    -f, --force             force operation
    -x, --maximum=DAYS      maximum password lifetime (root only)
    -n, --minimum=DAYS      minimum password lifetime (root only)
    -w, --warning=DAYS      number of days warning users receives before password
                            expiration (root only)
    -i, --inactive=DAYS     number of days after password expiration when an account
                            becomes disabled (root only)
    -S, --status            report password status on the named account (root only)
    --stdin                 read new tokens from stdin (root only)
  
  Help options:
    -?, --help              Show this help message
    --usage                 Display brief usage message
  [root@Server-n93yom ~]#

3.设置密码失效时间

• 可以编辑/etc/login.defs来设定几个参数，以后设置口令默认就按照参数设定为准：

  PASS_MAX_DAYS   99999
  PASS_MIN_DAYS   0
  PASS_MIN_LEN    5
  PASS_WARN_AGE   7

• 当然在/etc/default/useradd可以找到如下2个参数进行设置：

  # useradd defaults file
  GROUP=100
  HOME=/home
  INACTIVE=-1
  EXPIRE=
  SHELL=/bin/bash
  SKEL=/etc/skel
  CREATE_MAIL_SPOOL=yes

  通过修改配置文件，能对之后新建用户起作用，而目前系统已经存在的用户，则直接用chage来配置。

• chage [选项] 用户名

  chage命令是用来修改帐号和密码的有效期限。

  -m：密码可更改的最小天数。为零时代表任何时候都可以更改密码。
  -M：密码保持有效的最大天数。
  -w：用户密码到期前，提前收到警告信息的天数。
  -E：帐号到期的日期。过了这天，此帐号将不可用。
  -d：上一次更改的日期。
  -i：停滞时期。如果一个密码已过期这些天，那么此帐号将不可用。
  -l：例出当前的设置。由非特权用户来确定他们的密码或帐号何时过期。

• chage -l root 查root账号的信息

  [root@Server-n93yom ~]# chage -l root
  Last password change                    : Jul 22, 2019
  Password expires                    : never
  Password inactive                    : never
  Account expires                        : never
  Minimum number of days between password change        : 0
  Maximum number of days between password change        : 99999
  Number of days of warning before password expires    : 7
  [root@Server-n93yom ~]#

• chage -M 60 test  设置密码过期时间为60天

• chage -I 5 test    设置密码失效时间为5天

• 以test1账号为例，再查一次信息账号信息

  [root@Server-n93yom ~]# chage -l test1
  Last password change                    : Jul 22, 2019
  Password expires                    : Sep 20, 2019
  Password inactive                    : Sep 25, 2019
  Account expires                        : never
  Minimum number of days between password change        : 0
  Maximum number of days between password change        : 60
  Number of days of warning before password expires    : 7

  从上述命令可以看到，在密码过期后5天，密码自动失效，这个用户将无法登陆系统了。