Posts in category “Linux”


You might be surprised why I am using MSYS2 so much these days. In short, my new job doesn't allow me to use Linux at work. I cannot bear the CMD.EXE and PWSH.EXE, they might be great tools for someone else, but definitely not for me.

  1. If you visit a shared folder like /c/vagrant, you will get the infamous Too many levels of symbolic links error message. Fortunately, we have a solution: add a new user Environment variable MSYS=nonativeinnerlinks. I assume you know how to add a user environment to the windows system. If it doesn't take effect, save your current work and reboot. I didn't reboot my Windows 11 VM, but I did have restarted the Windows terminal application to ensure the new MSYS2 terminal will work with the links!
  2. If you prefer using Git for windows in MSYS2 but don't want to install GitBash because GitBash is also built on MSYS2, Install Git for windows inside MSYS2 will help you! BTW, git_bash_for_windows_is_based_on_msys2_why_not is another very good reference for this topic. I actually got the previous link from the latter article.
  3. Change the home directory to /c/Users/your-name. If you copy from the following, don't forget to change david.wei to your Windows username.
    $ cat /etc/nsswitch.conf
    # Begin /etc/nsswitch.conf
    passwd: db
    group: db
    db_enum: cache builtin
    #db_home: cygwin desc
    db_home: env windows /c/Users/david.wei
    db_shell: cygwin desc
    db_gecos: cygwin desc
    # End /etc/nsswitch.conf
  4. If you run cmd.exe in a msys2 terminal, that %PATH% environment will inherit from the PATH environment in the current bash session.
  5. put export MSYS="winsymlinks:lnk" into your .bashrc to get a similar behaviour when you do ln -s Reference

Fritz 7490: Root cause for Port mapping failure issue on a vagrant virtual machine


The root cause is that the default route was not set to the router's IP address.

My journey to resolve the issue:

The issue is that port mapping can work with my raspberry pi while it couldn't work with a virtual machine in the same LAN. I firstly think it must be a bug from the router. I upgrade the router to its latest firmware, but it still doesn't work. I google back and forth, I learned much from all kinds of answers, but they were just not my case. I almost decided to give up.

Then I found the following answer from E. van Putten, he answered this question and nobody gave his answer a "Like"!!!

In case you landed on this page because you can't reach a server running inside a Xen Guest from the internet (but can connect locally), then read on...

  1. The fritzbox can get confused by different OS'es appearing from the same MAC-address etc. (could happen while you are setting up / experimenting with Xen)
  2. The fritzbox has seemingly duplicate entries in the list, but with different settings, you need to delete the portmap from the incorrect entry, cleanup the list and reapply the portmap settings.
  3. It might be that your guest OS has no default gateway IP-address set. You'd expect a default gateway set to the local IP-address of your fritzbox. The symptoms of a missing default gateway is that your LAN PCs can access the server running inside the guest just fine, but external users from the internet cannot connect.

He gave three possible causes, and my case is the third one! here's my solution

opts = {
    :name => "yt-gateway",
    :ip => "",
    :mem => "1024",
    :cpu => "1"
Vagrant.configure("2") do |config| = "bento/ubuntu-20.04"
  config.vm.hostname = opts[:name] :public_network, ip: opts[:ip], bridge: "eno1"
  config.vm.provision "shell", run: "always", inline: "route add default gw || true"
  config.vm.provider "virtualbox" do |v| = opts[:name]
    v.customize ["modifyvm", :id, "--memory", opts[:mem]]
    v.customize ["modifyvm", :id, "--cpus", opts[:cpu]]
    v.customize ["modifyvm", :id, "--name", opts[:name]]

I love you E. van!

Setup PiVPN on a Vagrant virtual machine that is running Ubuntu 20.04

PiVPN should be easy to setup at any debian/ubuntu family distribution. However, my case wasn't.

  1. The first issue I met is Can't call method "set" on an undefined value at /usr/share/perl5/Debconf/ line 126, line 5., and I found a useful anwser from, which is
apt-get install --reinstall debconf

it worked! though I don't know the root cause.

  1. The second issue is rather weird, it simple stuck after showing ::: Backing up the openvpn folder... message. What's wrong with that on earth? Unfortunately, I couldn't find anything useful from google/stackoverflow.... I have to find out the root cause by myself.

ps -ef command shows there is a wget -qO- process running. Why it is running so long and looks never end? I copied the wget command and run it manually. aha, I found the cause!

--2021-10-10 23:01:15--
Resolving (
Connecting to (||:443... connected.
HTTP request sent, awaiting response... 302 Found
Location: [following]
--2021-10-10 23:01:15--
Resolving ( 2606:50c0:8002::154, 2606:50c0:8003::154, 2606:50c0:8001::154, ...
Connecting to (|2606:50c0:8002::154|:443... ^C

You could see, all of the IP addresses wget used are in IPV6 format while my network doesn't support IPV6 . So it is easy to fix. According to this question from stackoverflow, I added the following line at the end of /etc/wgetrc and the issue has gone!

inet4_only = on

Solved: XPS 15 on Pop OS 20.04 gui got stuck after updating firmware

Previously, I have updated the firmware several times, so when I saw there's a new update, I clicked the "Update" button without too much thoughts. Yes, I got trouble this time. I got a black screen while the system is not dead. I can log into the system by pressing Alt+Ctrl+F2, no gui, but I can do something to fix it. It is good enough. I searched on my cellphone to try find something. And the following article helped me.

System76 login-loop-pop

In my case, I guess that the root cause could be the nvidia driver, so I followed the [Reinstall NVIDIA Driver] section in that article and it did save my life.

# remove current driver
sudo apt purge ~nnvidia
sudo apt autoremove
sudo apt clean
# reinstall it
sudo apt update
sudo apt full-upgrade
sudo apt install system76-driver-nvidia

In case someone else got trapped into the same situation, I wrote my solution here and hope it helps.

PopOS/Ubuntu 20.04 fcitx-rime setup

By my recommendation, my new workmate He (贺) moved to Ubuntu from windows, and he was annoyed of one thing: cannot input Chinese. And I have to google again to find out the answer. This is why I wrote this list for him like people and myself.

sudo apt install fcitx fcitx-rime
im-config  # and select fcitx as the input engine
sudo reboot # important!
fcitx-configtool # choose the correct input method you need