Two ways to completely delete users under Linux

Linux Operation

Experimental environment: Centos7 virtual machine

First create a common user gubeiqing.

[root@localhost ~]# useradd gubeiqing
[root@localhost ~]# passwd gubeiqing
Changing password for user gubeiqing.
New password:
BAD PASSWORD: The password is a palindrome
Retype new password:
passwd: all authentication tokens updated successfully.

This successfully creates a normal user, and then deletes the user.

[root@localhost ~]# userdel gubeiqing
[root@localhost ~]#

Use the useradd command to delete it, but... the problem comes. When we create the user gubeiqing again:

[root@localhost ~]# useradd gubeiqing
useradd: warning: the home directory already exists.
Not copying any file from skel directory into it.
Creating mailbox file: File exists

The file already exists and cannot be created. Why? Because when a user is created, the user's home directory, password file, user group (if no user group is specified), and mailbox file are generated by default. When the userdel command is used to delete a user, only the user is deleted, but the user's files are still there, so these files need to be completely deleted. I took a look and found about four areas that needed to be addressed.

/home
/etc/passwd
/etc/group
/var/spool/mail

Let's delete these files one by one.

1. Delete files in the /home directory

[root@localhost ~]# cd /home
[root@localhost home]# ls
gubeiqing
[root@localhost home]# rm -rf gubeiqing
[root@localhost home]# ls
[root@localhost home]#

2. Delete users under /etc/passwd

We can take a look at this file.

[root@localhost ~]# 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-network:x:192:192:systemd Network Management:/:/sbin/nologin
dbus:x:81:81:System message bus:/:/sbin/nologin
polkitd:x:999:997:User for polkitd:/:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
chrony:x:998:996::/var/lib/chrony:/sbin/nologin
dockerroot:x:997:994:Docker User:/var/lib/docker:/sbin/nologin
gubeiqing:x:1000:1000::/home/gubeiqing:/bin/bash

Here you can see all the users in this system. You can see that the last line is the user you just created, so use the vi editor to delete the user in the last line.

3. Delete the user group files under /etc/group

Let’s check this file first:

[root@localhost ~]# 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-network:x:192:
dbus:x:81:
polkitd:x:997:
postdrop:x:90:
postfix:x:89:
sshd:x:74:
chrony:x:996:
cgred:x:995:
dockerroot:x:994:
gubeiqing:x:1000:

Then use the vi editor to delete this user group.

4. Delete the mailbox files under /var/spool/mail

[root@localhost ~]# cd /var/spool/mail
[root@localhost mail]# ls
gubeiqing
[root@localhost mail]# rm -rf gubeiqing
[root@localhost mail]# ls
[root@localhost mail]#

After the deletion is complete, create the gubeiqing user.

[root@localhost mail]# useradd gubeiqing
[root@localhost mail]# passwd gubeiqing
Changing password for user gubeiqing.
New password:
BAD PASSWORD: The password is a palindrome
Retype new password:
passwd: all authentication tokens updated successfully.

Done!

In addition to this method, there is also a method of completely deleting it.

[root@localhost mail]# userdel -rf gubeiqing
[root@localhost mail]# useradd gubeiqing
[root@localhost mail]# passwd gubeiqing
Changing password for user gubeiqing.
New password:
BAD PASSWORD: The password is a palindrome
Retype new password:
passwd: all authentication tokens updated successfully.

Using these two methods, you can completely delete a user.

Summarize

The above are two methods that I introduced to you to completely delete users under Linux. I hope it will be helpful to you. If you have any questions, please leave me a message and I will reply to you in time. I would also like to thank everyone for their support of the 123WORDPRESS.COM website!

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