authenticationarchlinux

Cannot switch from user myself back to root using `su` command, it reports authentication failure. `sudo` command not found either

I am currently using Arch Linux on WSL2, and I am new to it. In the previous time, I mostly used Ubuntu 18.04 on VMWare. I switch to Arch Linux and WSL2 is because I want to explore something new, and I learned from others that Arch is an interesting Linux distribution.

After installing Arch on WSL2, I added a new user called gwen and set the password, using the following commands:

[root@DESKTOP-ROOSFVQ ~]# useradd -m gwen
[root@DESKTOP-ROOSFVQ ~]# passwd gwen
New password:
Retype new password:
passwd: password updated successfully

After that, I used pacman -S vim to install thie vim editor.

When using Ubuntu, I set the user gwen when installation. I mostly log in as the user gwen, and it creates a directory for gwen. When I want to install some packages by apt, I use sudo apt install xxx. When I need some superuser permission, I add sudo before the command. But I mostly operate under the default user gwen.

So this time, I set the default user as gwen in the /etc/wsl.conf and restart the system. When the terminal is reopened, the default user changes to gwen indeed. The configuration in /etc/wsl.conf likes this:

[user]
default=gwen

But after that, when I want to install Git using pacman -S git, it reports an error

[gwen@DESKTOP-ROOSFVQ ~]$ pacman -S git
error: you cannot perform this operation unless you are root.

I know that there's no permission for user gwen to install packages, so I tried to switch back to user root.

[gwen@DESKTOP-ROOSFVQ ~]$ su
Password:
su: Authentication failure

There's no password for root when Arch Linux is installed. I have never set any password for it neither. So when entering password, I just press the Enter, and it says authentication failure. I also try the gwen password either, but it also says authentication failure.

I search for some similar questions, they say it could be solved by entering sudo su, I try it either, but it says sudo: command not found:

[gwen@DESKTOP-ROOSFVQ ~]$ sudo su
bash: sudo: command not found

Now I don't know what to do, can you give me some advice on how to solve it?

Solution

  • I am not sure, but it seems that sudo is not installed by default on Arch Linux and your user gwen is not in the sudoers group.

    You could try:

    1. Exit WSL completely

    2. Open Windows Command Prompt and run: wsl -u root

    3. This will log you back as root

    4. Then run bash

    5. Exit and restart WSL, after that, gwen should be able to use sudo.

    Alternative: you could also set a root password with passwd while you are root.