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2024-09

  • in System
  • 2 min read

Windows subsystem for Linux 2 (WSL2)

Set up Windows subsystem for Linux 2 (WSL2) for Linux development experience in Windows 10 and 11.

Instal WSL2

Open powershell with administrator privilege, run the following command in the host.

wsl --install --no-distribution

or install the components manually

dism.exe /online /enable-feature /featurename:Microsoft-Windows-Subsystem-Linux /all /norestart
dism.exe /online /enable-feature /featurename:VirtualMachinePlatform /all /norestart

After reboot, install the Linux distribution

wsl --update
wsl --set-default-version 2
wsl --install -d Ubuntu  # Or another Linux distribution

WSL2 post-install (optional) setup

Backup/move the virtual disk

If you want to move the WSL virtual disk file to another disk (in this example, D:\), run the following commands in Windows12:

wsl --export Ubuntu .\Ubuntu\ext4.tar
wsl --unregister Ubuntu
wsl --import Ubuntu D:\Ubuntu\ .\Ubuntu\ext4.tar

Default login user

Edit /etc/wsl.conf in the WSL. You may need to set the default user if you have moved the virtual disk file of the WSL distribution.

/etc/wsl.conf
[user]
default=username

Host settings

Edit .wslconfig 3 in your Windows home directory (%USERPROFILE%).

For example,

.wslconfig
[wsl2]
memory=20GB              # How much memory to assign to the WSL2 VM.
swap=8GB                 # How much swap space to add to the WSL2 VM. 0 for no swap file.
swapfile=C:\\temp\\wsl-swap.vhdx # Sets swap file path location, default is %USERPROFILE%\AppData\Local\Temp\swap.vhdx. Useful if your C drive has limited disk space.

Auto reclaim RAM and disk space

Edit .wslconfig 3 in your Windows home directory (%USERPROFILE%). 4

.wslconfig
[experimental]
autoMemoryReclaim=gradual    # Reclaim RAM usage
sparseVhd=true               # Reclaim virtual disk (vhd) usage

Maintenance

Update kernel

To (manually) update the WSL kernel, run the following commands with administrator privileges:

wsl --shutdown
wsl --update

Reclaim virtual disk space

Optimize-VHD

Note

Optimize-VHD is not available in Windows Home edition.

To reclaim disk space from virtual hard disks (VHDs), run the following commands with administrator privileges 5:

wsl --shutdown
Optimize-VHD -Path %path-to.vhdx% -Mode Full
Export and re-import

Alternatively, export the VHD as a tar file and reimport it again.

Caveats about WSL2

Poor filesystem performance across OSes

Cross-OS file access (e.g., accessing /mnt/c in WSL) is at least one order of magnitude (10x) slower than accessing natively (/home/user/).6

  1. https://learn.microsoft.com/zh-tw/windows/wsl/basic-commands#import-and-export-a-distribution ↩↩

  2. https://blog.iany.me/2020/06/move-wsl-to-another-drive/ ↩↩

  3. https://learn.microsoft.com/zh-tw/windows/wsl/wsl-config ↩↩↩↩

  4. https://devblogs.microsoft.com/commandline/windows-subsystem-for-linux-september-2023-update/ ↩↩

  5. https://blog.miniasp.com/post/2023/05/14/Shrink-your-WSL2-Virtual-Disks-and-Docker-Images-and-Reclaim-Disk-Space ↩↩

  6. https://neilbryan.ca/posts/win10-wsl2-performance/ ↩↩

  • in System
  • 1 min read

Check battery status

Open Windows Powershell with Administrator rights and run:

powercfg /batteryreport /output "C:\battery-report.html"

See the report at C:\battery-report.html.

  • in System
  • 1 min read

Install fonts in Linux

Copy the fonts files to ~/.local/share/fonts/. Then, run fc-cache to rebuild fonts cache.

fc-cache -fv
  • in DevOps
  • 1 min read

Git submodule

Frequently used commands for Git submodules.

Add a submodule

TO add the reference to another git project as a submodule:

git submodule add $url $path
git submodule update --init --recursive

Alternatively, you can use GUI tools like or GitHub desktop. They download and initiate submodules automatically.

Add you will see the file .gitmodules with information about the submodule(s). For instance,

.gitmodules
[submodule "themes/DoIt"]
    path = themes/DoIt
    url = https://github.com/HEIGE-PCloud/DoIt.git

Track a specific branch in the submodule

With -b $branch option

git submodule add -b $branch $url $path

Or set-branch -b $branch if you already have added a submodule

git submodule set-branch -b  $branch $path

Update all Git submodules to the latest commit

From a stackOverflow post and Git docs

git submodule update --remote --merge

For automated updates by bots, see automatic dependency update.

Remove a submodule

From Git docs

# Remove submodule from config
git submodule deinit $path
# Delete submodule tracking data
git rm <submodule path> && git commit
# Complete removal
rm -rf $GIT_DIR/modules/$name/