Redirect WSL input in Powershell - powershell

I've been trying to write a powershell script that automates my windows workspace setup and configuration and am currently stuck trying to redirect input to WSL when executing it for the first time. The core of the problem is that Ubuntu's first launch prompts for a username and password, then logs in to a bash shell. I tried writing down the input lines into a text file like so:
Username
Password
Password
exit
Then, I tried redirecting the input of wsl to the file:
Start-Process ubuntu2004.exe -RedirectStandardInput stdin.txt -NoNewWindow -Wait
The above didn't work as executing WSL just starts spamming Enter new UNIX username: adduser: only one or two names allowed. I tried doing same in CMD with the < input redirection, but the result is the same.

This is not exactly the answer to your question, but in my opinion, ansible is better suited for such a task.
I myself recently became interested in assembling a workspace in wsl and ansible seemed to me the best solution.
Before starting the build, you will need to perform minimal steps (create a user and install several packages, all this can be placed in the readme), but then there will be no restrictions.
You can find several ready-made examples of wsl assembly via ansible on github.

A few ideas for setting the username/password in a new Ubuntu WSL instance:
First, a "PowerShell sendkeys" via COM or Interop might work for this. It's probably the closest in behavior to what you are actually asking.
Second, and perhaps most promising, I just tried this with a new Debian WSL installed from the Store (since I didn't want to mess with my Ubuntu install).
When running debian.exe (like ubuntu2004.exe), I let it run the install, then I Ctrl+C'd out of it when it started asking for the default username/password. At that point, the WSL instance is installed, but with only root. I assume that your script can let the command run for a certain period of time, then kill the process to replicate this.
From your script, you should then be able to run wsl -u root useradd --create-home --user-group --groups adm,dialout,cdrom,floppy,sudo,audio,dip,video,plugdev,netdev --password "encryptedPassword" username (see here for creating the encrypted password). I think that will get you a stock Ubuntu user the way that WSL sets it up.
You'll then need to either create a /etc/wsl.conf file (instructions) letting the instance know that that user is the default, or LxRunOffline lists this as one of its features.
But I'd also throw in that you might just want to keep a "backup" of an existing WSL instance that you start from. Do a wsl --export <distroname> <imagename.tgz>, then you can import it when setting up the new Windows host by copying the tgz over and doing a wsl --import <DistroName> <DirectoryWhereYouwantItToLive> <imagename.tgz>.
If you want, you can keep this image up to date with your desired WSL configuration, so that you don't have to recreate it when you rebuild the Windows hosts. That said, this is where I do follow #Mystic's suggestion of using Ansible to store my WSL "configuration as code". It allows me to not only recreate my WSL instances, but also that same configuration when I set (or reset) a Linode host or another Linux system.

Related

Editing WSL2 instance of Ubuntu Crontab using Windows VSCode

My question is whether it is possible to edit the crontab of a WSL2-based instance of Ubuntu with my Windows VSCode that is connected via WSL remote SSH.
If I type export EDITOR=code inside my WSL instance and then crontab -e, I am able to see a /tmp/crontab.sygFAU file load inside my VSCode instance.
The problem is that once I make edits to this file, it will save the file to /tmp/crontab.sysFAU but it doesn't actually take the next step of replacing the the real crontab file in /var/spool/cron/crontabs.
So once I re-open the crontab, it will just show what I had previously, and not my saved edits.
It would be nice to know if this is not possible or if there are any alternative ways to run a GUI editor because using nano is a pain!
An interesting question that I haven't considered before, myself. Here's what's happening:
You set your editor to code
You crontab -e, which properly loads VSCode with the temporary crontab.
However, because this is a Windows GUI application, it returns control to the parent Linux application (crontab) immediately after starting VSCode. You can see the same result if you just start notepad.exe from your shell in WSL -- Once Notepad starts (rather than exits) control is returned to the shell.
If you switch back to your terminal at this point, you'll see that crontab detected that the editor that it launched exited (returned), and so it has already tried to copy the temporary file to the permanent location.
However, since the temporary files doesn't yet have any changes, crontab decides there's nothing to do.
Editing the file in VSCode and saving it has no effect, other than to leave a dangling /tmp/... file hanging around (since crontab isn't there to clean up).
So what's the solution? We need a way to launch a Windows GUI application and prevent it from returning control to crontab until you are done editing.
I originally thought something from this question might work, but the problem is that the actual command that launches the Windows process is embedded in a shell script, which you can see with less "$(which code)" (or code "$(which code)"), but it's probably not a great idea to edit this.
So the next-best thing I came up with is a simple "wrapper" script around the (already-a-wrapper) code command. Create ~/.local/bin/code_no_fork.sh (could be anywhere) with:
#!/usr/bin/env bash
code $* > /dev/null
echo Press Spacebar to continue
read -r -s -d ' '
Credit: This answer for the Spacebar approach
Then:
EDITOR=~/.local/bin/code_no_fork crontab -e
After you make your edits in VSCode, simply press Space to allow the script to continue/exit, at which point crontab will (assuming no errors were detected) install the new Crontab.
Alternatives
This is should typically only be a problem with Windows GUI applications, so the other possible avenue is to simply use any Linux editor that doesn't fork. If you want a GUI editor, that's entirely possible as long as you are running a WSL release that includes WSLg support (now available for Windows 10 and 11).
I won't offer any individual editor suggestions since that would get into "opinion" and "software recommendation" territory, which is off-topic here.

WSL2 doesn't work after using su to change user

I'm using WSL2 with the Remote - WSL extension for Visual Studio Code.
If I do code ., Visual Code opens in the specified folder. However, if I change user with su, the same command outputs:
Command 'code' not found, did you mean:
...
You seem to be running into this issue, where the Remote extension always uses the default user.
While no solution here is ideal, there are (at least) three options, depending on your exact use-case:
Temporarily change the default user:
You'll need to sudo -e /etc/wsl.conf and add:
[user]
default=other_username
Then wsl --terminate <distro> (from PowerShell, CMD, or the Start menu), then restart.
Use two different WSL instances with different default users in each one.
Possibly, give your default user permissions to whatever files you are trying to edit for the other user.

Installing interactive msi in Remote Machine with Powershell

I have a .msi file in my remote machine which is in a different domain from my local machine. I am able to connect to the remote machine with powershell but how can I install the msi there. The installation process has a lot of inputs to be given along with pressing 'Next' and then again giving a particular input and radio buttons and many more. Thus it is an interactive installation. In my local I am able to do it with [System.Windows.Forms.SendKeys] to imitate the keyboard inputs but as the process will be running in background in the remote machine I don't think SendKeys will work. And 'psexec' is not an option here because in my remote machine I cannot include PSTools with my Powershell. Is there any way to do it with Invoke-Command and -ArgumentList??
If there is a way then how can I choose sequentially whether to input a text in a particular field or click the next button or click any other button within the application window??
I finally got to solve this puzzle with the help of a automation tool called AutoIt. This tool has its own scripting language and can create .exe files to run a particular application and do the corresponding installation steps based on each successive window the application installer pops. After creating the .exe I copied it to my remote machine using Copy-Item or you can use robocopy, then invoked the .exe remotely with the help of psexec. As I had the misconception previously about psexec, it only needs to be integrated with powershell at the local and thus it automatically creates a session of its own and interacts with the remote machine. This is the command to run the .exe on remote machine:-
psexec -i 2 -s -d \\remote_machine_name -u Username -p Password C:\Path_to_exe\installer.exe
You can actually log on to the remote machine and see in the GUI that it is happening. And yes, obviously you need to have the .msi which will be called to be present there in the remote machine so that the .exe can do its job locally in the remote session.

Creating a bat file to run raspberry pi commands on windows

I am trying to set up a simple bat file to help non-tech people execute scripts by just clicking a file on desktop.
I haven't used windows in a while, and don't have a real dev environment set up on the computers they are going to be using. I installed putty, and can manually ssh into the pi's and run commands, but I can't teach that process to the employees.
I would like to create a simple bat file that runs the following commands:
ssh pi#192.168.1.xxx
<enter password>: 'xxx'
sudo reboot
Is there a way to do this?
Thank you!
Downloaded Plink #
https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html
I moved it, AND putty to c:/windows/system32 instead of changing PATH
This doesn't seem necessary, as the next step will automatically locate the file and change the path.
On desktop, right click and create a new shortcut.
In the shortcut path, I typed:
plink -ssh username#192.16.1.xxx -pw raspberry sudo reboot
This worked.
if you recheck the shortcut again, it should automatically change the path to execute plink

Is it possible to have Perl run shell script aliases?

Is it possible to have a Perl script run shell aliases? I am running into a situation where we've got a Perl module I don't have access to modify and one of the things it does is logs into multiple servers via SSH to run some commands remotely. Sadly some of the systems (which I also don't have access to modify) have a buggy SSH server that will disconnect as soon as my system tries to send an SSH public key. I have the SSH agent running because I need it to connect to some other servers.
My initial solution was to set up an alias to set ssh to ssh -o PubkeyAuthentication=no, but Perl runs the ssh binary it finds in the PATH instead of trying to use the alias.
It looks like the only solutions are disable the SSH agent while I am connecting to the problem servers or override the Perl module that does the actual connection.
Perhaps you could put a command called ssh in PATH ahead of the ssh which runs ssh as you want it to be run.
Alter the PATH before you run the perl script, or use this in your .ssh/config
Host *
PubkeyAuthentication no
Why don't you skip the alias and just create a shell script called ssh in a directory somewhere, then change the path to put that directory before the one containing the real ssh?
I had to do this recently with iostat because the new version output a different format that a third-party product couldn't handle (it scanned the output to generate a report).
I just created an iostat shell script which called the real iostat (with hardcoded path, but you could be more sophisticated), passing the output through an awk script to massage it into the original format. Then, I changed the path for the third-party program and it started working fine.
You could declare a function in .bashrc (or .profile or whatever) with that name. It could look like this (might break):
function ssh {
/usr/bin/ssh -o PubkeyAuthentication=no "$#"
}
But using a config file might be the best solution in your case.