Bash/WSL - How to run command as root?

Question

>ubuntu1804.exe -c "echo $USER"
mpen  

That runs the command as me, how do I run it as root?

The help page doesn't even mention -c

>ubuntu1804.exe help
Launches or configures a Linux distribution.

Usage:
    <no args>
        Launches the user's default shell in the user's home directory.

    install [--root]
        Install the distribuiton and do not launch the shell when complete.
          --root
              Do not create a user account and leave the default user set to root.

    run <command line>
        Run the provided command line in the current working directory. If no
        command line is provided, the default shell is launched.

    config [setting [value]]
        Configure settings for this distribution.
        Settings:
          --default-user <username>
              Sets the default user to <username>. This must be an existing user.

    help
        Print usage information.

Opine

Answer 1

Turns out there's another command simply called wsl that lets you run arbitrary commands as arbitrary users:

>wsl -u root -d Ubuntu-18.04 -- echo "I am g$USER"
I am groot

N.B. you need to use separate args (instead of a string) for this one.

-d is optional. You can change the default distro like

wslconfig.exe /l
wslconfig.exe /s Ubuntu-18.04
wslconfig.exe /l

wslconfig /l appears to be equivalent to wsl --list

Opine

You win the internet for your echo example, as far as I'm concerned. Maybe it's an old joke by now, but I voted up your solution for that alone. – Mateya

Answer 2

Often the root account is not active by default

Do this (it will prompt you to select the password for root):

sudo passwd root

and then you can login as root:

su root

After you have done with activities that request root privileges, re-login back as user:

su <username>

Unfasten

You should use su - root, or, in general, su - <username> to log in with full user environment. To logout, you should use logout or simply Ctrl + D (in almost every terminal). Using su again will start a new session over the pre-existing root and the original user sessions. – Ruella

Answer 3

First list all your wsl distributions. In my case, Ubuntu is default.

wsl -l

Since ubuntu is default, all you need is "-u" flag to run a command as root.

wsl -u root "whoami"

If ubuntu is not default, you can either set it as default if you want

wsl -s ubuntu

Or, specify that you want to run this in ubuntu environment

 wsl -d ubuntu -u root "whoami"

Sematic

Answer 4

If you need to run multiple commands, just login as root:

wsl -u root

and run all commands interactively

Guanidine

If you're able to run commands interactively, you can just use sudo or su as normal. If you need to run multiple commands from Windows non-interactively, you can do wsl -u root -- sh -c 'echo foo && echo bar' – Opine

@Opine I had to run commands interactively to add my user to the sudo group :-) – Guanidine