John Rennie's questions

I'm asking on behalf of a friend's son who is at college in India, so apologies if what I ask doesn't have enough information. He is using WSL2 on Windows 11 and has Ubuntu 22.04.3 LTS installed.

His prof has given these instructions for mounting an NFS share needed for the course:

sudo apt-get install nfs-common
cd /
sudo mkdir tools
sudo mount -t nfs 10.0.17.82:/tools /tools

The first three commands work fine but the mount fails. I got him to add a -v flag and the output is:

minor@Tejas:~$ sudo mkdir /tools
[sudo] password for minor:
minor@Tejas:~$ ls /tools
minor@Tejas:~$ sudo mount -v -t nfs 10.0.17.82:/tools /tools
mount.nfs: timeout set for Sun Sep  8 15:10:40 2024
mount.nfs: trying text-based options 'vers=4.2,addr=10.0.17.82,clientaddr=172.29.144.144'
mount.nfs: mount(2): Invalid argument
mount.nfs: trying text-based options 'vers=4,minorversion=1,addr=10.0.17.82,clientaddr=172.29.144.144'
mount.nfs: mount(2): Operation not permitted
mount.nfs: trying text-based options 'addr=10.0.17.82'
mount.nfs: prog 100003, trying vers=3, prot=6
mount.nfs: trying 10.0.17.82 prog 100003 vers 3 prot TCP port 2049
mount.nfs: prog 100005, trying vers=3, prot=17
mount.nfs: trying 10.0.17.82 prog 100005 vers 3 prot UDP port 20048
mount.nfs: mount(2): Permission denied
mount.nfs: Operation not permitted
minor@Tejas:~$

I asked him to use showmount and the result was:

minor@Tejas:~$ showmount -e 10.0.17.82
Export list for 10.0.17.82:
/ *

I can't see a /tools export in the list, but then I don't know if I should be able to see it. It's entirely possible his prof has not configured the server properly.

Anyhow can anyone suggest what is wrong, or further steps to check what the problem is?

In my role as a tutor I often have to set up test Ubuntu installations to help students that use Ubuntu - I myself use Windows (sorry!).

For convenience I always install xrdp, and I found out by Googling and lots of experiment that I need to also install xorgxrdp. Then I can RDP to the test installations from my Windows workstation and this all works very well.

If I don't install xorgxrdp my RDP session just shows a blank screen. There are lots of questions about this already, and I vaguely grasp that xorgxrdp is an interface between xrdp and xvnc, so I'm not asking how to fix the blank screen. Instead I would be interested to know what exactly has happened if I make the connection without installing xorgxrdp. The connection has obviously established some form of graphical session because the mouse works, and I see the Ubuntu cursor in my RDP window not the Windows cursor. Can I do anything with this connection? Is there any way of running a graphical application?

I am using Ubuntu 20.04 in the Windows subsystem for Linux on Windows 10. When I type the who command I get no output:

renniej@ratitch:~$ whoami
renniej
renniej@ratitch:~$ who
renniej@ratitch:~$

I have tried various things like sudo who and who -a but still I get no output. who --version gives:

who (GNU coreutils) 8.30
Copyright (C) 2018 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by Joseph Arceneaux, David MacKenzie, and Michael Stone.

Am I doing something silly here? Or is this a feature of WSL2?

Some background: I look after the key handling code in the Kodi media centre software, and I've been trying to pin down an obscure bug reported by a user. They have a remote control that emulates a keyboard and for a particular button sends the key combination Ctrl+Shift+Alt+b. The trouble is that the keypress Kodi receives is Ctrl+Shift+Meta+b.

I've discovered this also happens when I press that key combination on the keyboard, and in fact any combination involving shift and Alt does similar things. The common factor seems to be having Shift and Alt pressed simultaneously.

I understand that the Meta key was a modifier key on an old keyboard that is no longer used, but that Ubuntu can be configured to generate Meta keypresses. I wonder if there is a setting somewhere in Ubuntu that is causing the Shift+Alt combination to be sent to X clients as a Meta keypress.

This is with Ubuntu 14.04, and I get the same behaviour in the standard shell and when using the LXDE shell.

Please shout if I've missed out any vital info - I'm a Windows developer and am a bit out of my depth with unix. I haven't gone into the details of the system calls Kodi uses to receive the key presses as I suspect that's more suited to a development site. What I'm primarily interested in is some setting that is user tweakable that might be causing this behaviour.