Configuring MSY2 Bash for Codex (on Windows)

[Nonary]

Currently Codex CLI on Windows isn't as great as it is on WSL but it is possible to configure the shell as bash and retain all the same benefits as Linux does and it doesn't even require WSL.

Quick summary

• Install MSYS2 (default: C:\msys64).
• Point PowerShell’s bash to MSYS2’s bash.
• In your MSYS2 bash profile, put ucrt64 first in PATH and add VS Code’s bin.
• Update MSYS2 and install ripgrep (rg).
• Launch PowerShell → bash -l → run code . or codex.

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1) Install MSYS2 (ucrt64)

Install MSYS2 (default location is C:\msys64). If you installed elsewhere (e.g., D:\Software\MSYS2), just swap paths accordingly below.

2) Make PowerShell’s bash point to MSYS2

Open your PowerShell profile (creates it if missing), then add the alias.

Note: This assumes you have VS Code installed, if you use another IDE swap out code with it (notepad/cursor/etc)

if (-not (Test-Path $PROFILE)) { New-Item -Type File -Force $PROFILE | Out-Null }
code $PROFILE

Add one of these lines (pick the path where you installed MSYS2):

# Default install
Set-Alias -Name bash -Value 'C:\msys64\usr\bin\bash.exe'

# Custom install example
# Set-Alias -Name bash -Value 'D:\Software\MSYS2\usr\bin\bash.exe'

Save, then in PowerShell run:

bash -l

-l starts a login shell so your ~/.bash_profile is applied.

3) Set up your MSYS2 bash PATH (ucrt64 first)

In the bash window, create/edit your profile:

nano ~/.bash_profile

Add this (default install path shown first). Keep the ucrt64/bin entry before usr/bin so tools come from ucrt64:
If you have the user installation version of VS Code, don't forget to replace ${USERNAME} with your actual user name on windows.

# --- MSYS2 (default C:\msys64) ---
export PATH="/c/msys64/ucrt64/bin:/c/msys64/usr/bin:/c/Users/${USERNAME}/AppData/Local/Programs/Microsoft VS Code/bin:$PATH"

# If VS Code is system-wide instead of per-user, use:
# export PATH="/c/msys64/ucrt64/bin:/c/msys64/usr/bin:/c/Program Files/Microsoft VS Code/bin:$PATH"

# --- OR, if you installed MSYS2 somewhere else (example D:\Software\MSYS2) ---
# export PATH="/d/Software/MSYS2/ucrt64/bin:/d/Software/MSYS2/usr/bin:/c/Users/${USERNAME}/AppData/Local/Programs/Microsoft VS Code/bin:$PATH"

Save, then reload your profile:

source ~/.bash_profile

4) Update MSYS2 and install ripgrep (rg)

Open the MSYS2 UCRT64 shell (or just stay in this bash) and run:

pacman -Syu        # update package database + upgrade
# if it asks to close/reopen the shell, do that and run -Syu again

pacman -S mingw-w64-ucrt-x86_64-ripgrep

Sanity checks:

which bash
which rg
rg --version
which code

5) Daily usage

1. Open PowerShell
2. Start bash with your profile:

bash -l

3. From bash, run your tools so they inherit the bash environment:

cd /c/path/to/your/project
code .          # VS Code uses the bash environment
# or
codex           # if you use Codex CLI

That’s all, launching VS Code (or Codex) from bash makes its terminals/tasks prefer bash commands, matching the Linux experience.

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Tips & gotchas

• If code isn’t found in bash, double-check that VS Code’s bin folder is in the PATH you added (…/Microsoft VS Code/bin), then source ~/.bash_profile and try again.

• If you see the wrong rg or other tools, run which rg and ensure the path points to /ucrt64/bin. PATH order matters.

• You can make VS Code’s integrated terminal default to this bash by setting:

  • Settings → Terminal → Default Profile (Windows) → add/open a profile that points to your bash.exe in C:\msys64\usr\bin\bash.exe, then set it as default.

Sometimes Codex will still try to use powershell commands, to fix that, update Agents.md file to say always run every command through bash -lc

[LaelLuo]

I have an even stranger problem. My plan is to use Git Bash, which is essentially no different from using MSYS2. Initially, I installed Git and ripgrep (rg) via Scoop. However, I discovered that Codex ends up running on WSL. I traced this to the fact that C:\Windows\System32 contains a bash.exe, and I have no idea why it’s there.

I tried lowering that path’s priority in PATH, but it didn’t help—system-wide directories always come first. So I restored the original PATH, installed Git globally, and bumped the priority of Scoop’s global shims. After that, running bash in PowerShell correctly launches Git’s Bash.

Yet, as I mentioned in my issue #3159 , Codex still calls WSL’s bash --version on startup. I’m completely stumped and have no idea how to fix this.

[Nonary]

I have an even stranger problem. My plan is to use Git Bash, which is essentially no different from using MSYS2. Initially, I installed Git and ripgrep (rg) via Scoop. However, I discovered that Codex ends up running on WSL. I traced this to the fact that C:\Windows\System32 contains a bash.exe, and I have no idea why it’s there.

I tried lowering that path’s priority in PATH, but it didn’t help—system-wide directories always come first. So I restored the original PATH, installed Git globally, and bumped the priority of Scoop’s global shims. After that, running bash in PowerShell correctly launches Git’s Bash.

Yet, as I mentioned in my issue #3159 , Codex still calls WSL’s bash --version on startup. I’m completely stumped and have no idea how to fix this.

Try doing this to your powershell profile:

You'll need to fix the paths to match your system

Set-Alias -Name bash -Value "D:\Software\MSYS2\usr\bin\bash.exe" -Force
$env:PATH = "D:\Software\MSYS2\ucrt64\bin;" + $env:PATH

This forces MSYS2 bash to have higher priority than the WSL bash.

[Nonary]

I would be careful with git bash however, I have heard it causes problems with the Codex IDE plugin where it just fails to load without any obvious errors