WSL2 installation of Ubuntu-20.04 and configuration

---

Timeline

Timeline

2025-12-29

init

This article describes the complete process of installing Ubuntu-20.04 in WSL2 and configuring the environment. It includes migrating the WSL distribution to the D drive to save system space, as well as commands to restore the default user after migration. The article details the steps to compile and install the latest version of Emacs from source, including configuration options such as disabling X11, enabling native-comp, dynamic modules, multithreading, and tree-sitter support. In addition, it covers methods for upgrading and installing other development tools, such as obtaining the latest QEMU by compilation, installing a newer clangd, updating the git version, upgrading Python to above 3.9, and using bear written in Rust to replace the old Python script. The article aims to help users build an efficient and customizable development environment in WSL2.

---

Download Ubuntu for WSL

# View available downloadable images
wsl --list --online
# Download Ubuntu 20.04
wsl --install -d Ubuntu-20.04

Migrate to D drive

Create a directory on the D drive to store the new WSL, for example D:\WSL\Ubuntu-20.04

# 1. Export its backup (for example, named Ubuntu.tar)
wsl --export Ubuntu-20.04 D:\WSL\Ubuntu-20.04.tar
# 2. Unregister the original one
wsl --unregister Ubuntu-20.04
# 3. Restore the backup file to D:\WSL\Ubuntu-20.04
wsl --import Ubuntu-20.04 D:\WSL\Ubuntu-20.04 D:\WSL\Ubuntu-20.04.tar
# At this point, you can delete Ubuntu-20.04.tar

If you start WSL at this point, you may find that it seems to have recovered, but the user has become root. Use the following command to restore:

Ubuntu2004 config --default-user username

Install the latest version of Emacs

You can install a newer gcc compiler

sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt update

sudo apt install gcc-13 g++-13

sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-9 90
sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-9 90
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-13 130
sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-13 130

# If you want to change it later, use the following command
sudo update-alternatives --config gcc

Compile Emacs

# Optional: Uninstall snapd
sudo apt-get purge snapd
# Compile tree-sitter
git clone https://github.com/tree-sitter/tree-sitter.git
cd tree-sitter
git checkout release/0.25
make
make install PREFIX="$(pwd)/_install"
# Fix the prefix in the .pc file (change the prefix line to the following path)
nano _install/lib/pkgconfig/tree-sitter.pc
# prefix=/home/zhaohang/repository/tree-sitter/_install

# Set environment variables in ~/.bashrc or ~/.zshrc
export PKG_CONFIG_PATH="$HOME/repository/tree-sitter/_install/lib/pkgconfig:$PKG_CONFIG_PATH"

# Download the Emacs source code
wget https://mirrors.ustc.edu.cn/gnu/emacs/emacs-30.2.tar.xz
cd emacs-30.2
sudo apt install cmake build-essential
sudo apt install zlib1g-dev pkg-config libgnutls28-dev libncurses-dev libjansson-dev libvterm-dev libgccjit-$(gcc -dumpversion)-dev


export LD_LIBRARY_PATH="$HOME/repository/tree-sitter/_install/lib:$LD_LIBRARY_PATH"

./configure \
    --without-x \
    --without-ns \
    --without-pgtk \
    --with-native-compilation \
    --with-modules \
    --with-threads \
    --with-tree-sitter \
    --prefix=/usr/local \
    LDFLAGS="-Wl,-rpath,$LD_LIBRARY_PATH -L$LD_LIBRARY_PATH"

make -j$(nproc)
sudo make install
# After compilation, test it; it should output: RUNPATH /home/zhaohang/repository/tree-sitter/_install/lib:
objdump -p /usr/local/bin/emacs | grep RUNPATH

• --without-xemacs-nox, does not use X11 (Xorg), can only use emacs -nw (terminal)
• --without-nsDisable the Cocoa/NS window system on macOS, just to prevent configure from auto-detecting the macOS GUI
• --without-pgtkDisable Pure GTK (the new GUI backend under Wayland)
• --with-native-compilationEnable native-comp (.eln) to compile Elisp into machine code
• --with-modulesEnable dynamic module support, requires libjansson-dev
• --with-threadsEnable multi-threading support
• --with-tree-sitterEnable tree-sitter
• --prefix=/usr/localInstall to /usr/local

Emacs configuration reference:

MineEmacsConfiguration

https://even629.com/posts/28521

Reference for compiling the latest version of QEMU

QemuCompilation

https://even629.com/posts/2511219

In addition, the clangd version downloaded via apt is relatively old and may not support certain configuration options. You can install a newer version with the following command.

wget https://apt.llvm.org/llvm.sh
chmod u+x llvm.sh
sudo ./llvm.sh 21
sudo apt-get install clang-format-21

# Install clang into the alternatives system
sudo update-alternatives --install /usr/bin/clang clang /usr/bin/clang-21 100
sudo update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-21 100
sudo update-alternatives --install /usr/bin/clangd clangd /usr/bin/clangd-21 100
sudo update-alternatives --install /usr/bin/clang-format clang-format /usr/bin/clang-format-21 100
# Install libstdc++-10
sudo apt install libstdc++-$(gcc -dumpversion)-dev

The git version is too low and does not support-bparameter, you can add an apt source to update

sudo add-apt-repository ppa:git-core/ppa -y
sudo apt update
sudo apt upgrade
sudo apt install git -y

The Python version is 3.8; some software may depend on version 3.9 or higher:

sudo add-apt-repository ppa:deadsnakes/ppa
sudo apt-get update
sudo apt-get install python3.9 python3-pip

# Register python3.9 with priority set to 2
sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.9 2
# Register python3.8 with priority set to 1, so that its priority is lower than python3.9
sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.8 1

# Select the default version
sudo update-alternatives --config python3

Bear can also use the latest version. The old version of Bear is a Python script with low efficiency, while the new version is a binary written in Rust.

# Download Rust
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
# cargo 换源 visit https://mirrors.tuna.tsinghua.edu.cn/help/crates.io-index.git/
rustup update
# Compile Bear
git clone https://github.com/rizsotto/Bear.git
cd bear
cargo build --release

sudo install -m 755 target/release/bear /usr/local/bin/
# For Debian based systems
export INSTALL_LIBDIR=lib/x86_64-linux-gnu
sudo mkdir -p /usr/local/libexec/bear/$INSTALL_LIBDIR
sudo install -m 755 target/release/libexec.so /usr/local/libexec/bear/$INSTALL_LIBDIR/

WSL2 Ubuntu20.04

References

[1]

Install Ubuntu on WSL 2

[2]

Easy migration！Teach you how toWSLFromCmigrate a disk to another partition，Free up storage space！

[3]

treesit-install-language-grammar warning