linux学习lesson12-优快云博客

1 usermod命令

修改用户的uid

[root@worker1 ~]# usermod -u 1111 user3

[root@worker1 ~]# tail -n3 /etc/passwd

user1:x:1001:1001::/home/user1:/bin/bash

user2:x:1002:1002::/home/user2:/bin/bash

user3:x:1111:1100::/home/user3:/bin/bash

修改用户gid

[root@worker1 ~]# tail -n3 /etc/passwd

user1:x:1001:1001::/home/user1:/bin/bash

user2:x:1002:1002::/home/user2:/bin/bash

user3:x:1111:1100::/home/user3:/bin/bash

[root@worker1 ~]# usermod -g 1100 user2

[root@worker1 ~]# tail -n3 /etc/passwd

user1:x:1001:1001::/home/user1:/bin/bash

user2:x:1002:1100::/home/user2:/bin/bash

user3:x:1111:1100::/home/user3:/bin/bash

修改用户的shell

[root@worker1 ~]# tail -n3 /etc/passwd

user1:x:1001:1001::/home/user1:/bin/bash

user2:x:1002:1100::/home/user2:/bin/bash

user3:x:1111:1100::/home/user3:/bin/bash

[root@worker1 ~]# usermod -s /sbin/nologin user3

[root@worker1 ~]# tail -n3 /etc/passwd

user1:x:1001:1001::/home/user1:/bin/bash

user2:x:1002:1100::/home/user2:/bin/bash

user3:x:1111:1100::/home/user3:/sbin/nologin

把用户扩展到另外一个组

[root@worker1 ~]# usermod -G user2 user3

[root@worker1 ~]# id user3

uid=1111(user3) gid=1100(grp2) groups=1100(grp2),1002(user2)

2 用户密码管理

[root@worker1 ~]# tail /etc/shadow

systemd-network:!!:17779::::::

dbus:!!:17779::::::

polkitd:!!:17779::::::

tss:!!:17779::::::

postfix:!!:17779::::::

sshd:!!:17779::::::

user:!!:17783:0:99999:7:::

user1:!!:17791:0:99999:7:::

user2:!!:17792:0:99999:7:::

user3:!!:17792:0:99999:7:::

第二个字段是加密字符串，如果是两个!!密码是空的，不能登录；如果是*，是被锁定的，不能登录

设置user3的密码

[root@worker1 ~]# passwd user3

Changing password for user user3.

New password:

BAD PASSWORD: The password is shorter than 8 characters

Retype new password:

passwd: all authentication tokens updated successfully.

[root@worker1 ~]# tail -n3 /etc/shadow

user1:!!:17791:0:99999:7:::

user2:!!:17792:0:99999:7:::

user3:$6$Y2NKQ1ca$yp/S28D1A/WQ2RI.RBFYXqEJJKiUiZWgDnb5noXvDH56Qsldaw79mjIaLvZsTcIuCdzsK3G.oYfM3Gmm/WD0p1:17792:0:99999:7:::

锁定user3用户，这样就不能登录了，密码段前会有!!

[root@worker1 ~]# passwd -l user3

Locking password for user user3.

passwd: Success

[root@worker1 ~]# tail -n3 /etc/shadow

user1:!!:17791:0:99999:7:::

user2:!!:17792:0:99999:7:::

user3:!!$6$Y2NKQ1ca$yp/S28D1A/WQ2RI.RBFYXqEJJKiUiZWgDnb5noXvDH56Qsldaw79mjIaLvZsTcIuCdzsK3G.oYfM3Gmm/WD0p1:17792:0:99999:7:::

解锁user3，密码段去掉了!!

[root@worker1 ~]# passwd -u user3

Unlocking password for user user3.

passwd: Success

[root@worker1 ~]# tail -n3 /etc/shadow

user1:!!:17791:0:99999:7:::

user2:!!:17792:0:99999:7:::

user3:$6$Y2NKQ1ca$yp/S28D1A/WQ2RI.RBFYXqEJJKiUiZWgDnb5noXvDH56Qsldaw79mjIaLvZsTcIuCdzsK3G.oYfM3Gmm/WD0p1:17792:0:99999:7:::

更改用户密码便捷方法

方法1

[root@worker1 ~]# echo "654321"|passwd --stdin user3
Changing password for user user3.
passwd: all authentication tokens updated successfully.

方法2

[root@worker1 ~]# echo -e "123456\n123456" | passwd user3

Changing password for user user3.

New password: BAD PASSWORD: The password is shorter than 8 characters

Retype new password: passwd: all authentication tokens updated successfully.

3 mkpasswd命令

命令mkpasswd用于生成密码。我们安装的Linux默认是没有这个命令的，需要安装一个expect软件包

[root@worker1 ~]# yum install -y expect

-l 指定字符串长度

-s 指定特殊符号

-d 指定字符串数字的个数

[root@worker1 ~]# mkpasswd -l 12

25cbtoo|XgzR

[root@worker1 ~]# mkpasswd -l 12 -s 5

#;s|7$-FB7re

[root@worker1 ~]# mkpasswd -l 12 -s 0

mod0PL5ppqgr

[root@worker1 ~]# mkpasswd -l 12 -d 6

7_40kw7CU9a8