Launching MSYS2 Inside a WSL tmux Session

This setup allows you to start a WSL tmux session from MSYS2 and then launch an interactive MSYS2 shell inside that tmux session. It combines the convenience of running tmux in WSL with the familiar MSYS2 environment.

Purpose

The main goal is to keep tmux running in WSL while using MSYS2 as the interactive shell inside each tmux pane or window. This approach lets you manage terminal sessions with WSL tmux while continuing to work with MSYS2 tools.

The launcher script starts WSL, connects to a dedicated tmux server, and passes the required environment variables so that MSYS2 starts correctly.

Launcher Script

The launcher script performs the following tasks:

• Exports the environment variables required by both WSL and MSYS2.
• Prevents automatic path conversion where it is not desired.
• Starts tmux inside the target WSL distribution.
• Uses a dedicated tmux socket and configuration file.

With this script, you can launch or attach to the tmux session directly from MSYS2.

tmux Configuration

The tmux configuration changes the default command so that every new pane starts an MSYS2 shell instead of a Linux shell.

Before launching MSYS2, the configuration clears the PWD environment variable and updates WSLENV so that the necessary environment variables are available inside the MSYS2 process. It then starts an interactive MSYS2 Bash session.

The configuration also adds MSYSTEM and WSLENV to tmux's update-environment list. This ensures that newly created panes inherit the correct environment.

How to Use

1. Save the launcher script and make it executable.
2. Place the tmux configuration in the specified configuration file.
3. Run the launcher script from MSYS2.
4. A WSL tmux session will start, and each new pane or window will automatically open an MSYS2 shell.

This setup provides a simple way to use WSL tmux as the session manager while working in the MSYS2 environment.

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wrapper executed on msys2:

#!/usr/bin/env bash
set -euo pipefail

export WSLENV="MSYSTEM${WSLENV:+:$WSLENV}"
export MSYS2_ARG_CONV_EXCL='*'
export MSYS2_ENV_CONV_EXCL="WSLENV;TMUX;TMUX_PANE${MSYS2_ENV_CONV_EXCL:+;$MSYS2_ENV_CONV_EXCL}"

exec wsl.exe -d tmux --exec tmux \
    -L msys2 \
    -f /path/to/tmux-msys2.conf \
    "$@"

tmux-msys2.conf inside WSL:

set-option -g default-command '
unset PWD
WSLENV="MSYSTEM:PWD/p:$WSLENV"
exec /mnt/c/msys64/usr/bin/bash.exe --login -i
'
set-option -ag update-environment MSYSTEM
set-option -ag update-environment WSLENV