Piping to less doesn't work with WSL2 distro

[Praful]

Describe the bug
I have followed the instructions to map various Linux command, including less. If I try to pipe output via less, the command hangs at the colon prompt until I hit CTRL-C. This happens on a distro running as WSL v2. Version 1 distros are fine.

To Reproduce
Steps to reproduce the behavior:

1. Install WslInterop.
2. Add following line to PS profile:

Import-WslCommand "apt", "awk", "grep", "head", "less", "sed", "seq", "tail", "dos2unix", "du", "df", "wget", "gzip", "cat", "free", "top", "uname", "wc"

3. Install Ubuntu from Microsoft Store.
4. Set this to the default:

wsl -s Ubuntu

5. Set to WSL 2:

wsl --set-version Ubuntu 2

6. In new PowerShell (using Windows Terminal), type:

cd <a folder with more than a page of files>
ls | less

The command hangs at :. You can't, for example, press f or b.

Expected behavior
Piping output to less should allow you to page up/down, search, etc.

Screenshots
N/A

Desktop (please complete the following information):

• OS: Windows 10 20H2
• PowerShell v7.1.2

Additional context
Changing the distribution to WSL 1 fixes the issue:

wsl --set-version Ubuntu 1

In a new Terminal session, the following now works as expected:

ls | less

Thank you for providing this incredibly useful module.

[mikebattista]

Thanks for reporting. I can repro on my machine as well. Actually just running dir | wsl less is also broken, so it appears to be some regression with WSL 2 and nothing specific to this module.

@craigloewen-msft any ideas what could be going on here?

[craigloewen-msft]

I was able to repro this on my machine as well. Not sure what could be causing this but I'll file a bug for this on the WSL team and investigate!

[Praful]

@mikebattista - for this issue, I have set up WSL so that the default distro runs v1 and another distro runs v2. v2 works better with an xserver that I use to run Linux GUI apps. (I saw today that WSL is going to officially support Linux GUI apps :))

Ideally, I'd like the default to be v2 (so that I can just type wsl). Is there a way to tell wslinterop to use a specific distro - something like wsl -d <distro>?

[mikebattista]

Not right now, but it could be easy to add. Now it relies on the default WSL distro (set by wsl -s) which in your case sounds like it would be the v1 distro, and you don't want to change that. Is that correct? Or would you be willing to change your default to the v2 distro via wsl -s? The benefit of that would be that any explicit wsl calls you make that don't go through WslInterop would also use the v2 distro without having to specify it.

If you're not willing to change your default WSL distro via wsl -s, when using wsl directly to pass through commands, if you add -d <nondefaultdistro> before the command to pass through (e.g. wsl -d <nondefaultdistro> ls), does that successfully invoke the command in the <nondefaultdistro>?

If so, I could add support like $WslDefaultParameterValues["-d"] = "<nondefaultdistro>" which would then get passed through to the wsl command via -d. So you could add that to your profile and all WslInterop calls will go through the v2 distro even if your default distro set in wsl is the v1 distro.

[Praful]

Yes, please add a -d option.

I'd like to change my default WSL distro to v2, which currently doesn't work because of this issue. The new option will let me point WslInterop to a (non-default) v1 distro until the WSL team fix the WSL2 regression. Thanks

[Praful]

I was able to repro this on my machine as well. Not sure what could be causing this but I'll file a bug for this on the WSL team and investigate!

@craigloewen-msft what is the issue number for the bug you filed? I can't see it on WSL github. Maybe it's fixed in the latest preview?

[mikebattista]

Yes, please add a -d option.

I'd like to change my default WSL distro to v2, which currently doesn't work because of this issue. The new option will let me point WslInterop to a (non-default) v1 distro until the WSL team fix the WSL2 regression. Thanks

Could you try the changes at https://github.com/mikebattista/PowerShell-WSL-Interop/blob/wsl-d-parameter/WslInterop.psm1?

Just replace the .psm1 file on your system with the one from that branch, start a new PS session, then set $WslDefaultParameterValues["-d"] = "<distro>".

[craigloewen-msft]

I was able to repro this on my machine as well. Not sure what could be causing this but I'll file a bug for this on the WSL team and investigate!

@craigloewen-msft what is the issue number for the bug you filed? I can't see it on WSL github. Maybe it's fixed in the latest preview?

I filed an issue for this on our internal tracking

[Praful]

Just replace the .psm1 file on your system with the one from that branch, start a new PS session, then set $WslDefaultParameterValues["-d"] = "<distro>".

Thank you very much for the quick change. That works perfectly!

[mikebattista]

Awesome. I just published 0.3.0 of the WslInterop package with the changes.

I'm going to close this as the remaining bug is in WSL 2 and @craigloewen-msft is tracking that separately.

[mikebattista]

https://task.ms/32245206