Undeletable nul file

@harunurhan

Open Code creates a nul file on the root directory of the project. That file can't be deleted on Windows.

Versions where the bug was reported

I personally encountered the bug using v1.1.60 on Windows 11 Pro 25H2...
... and using 1.1.59 on Windows 11 Home 24H2.
@harunurhan reported the bug on 1.1.27
@rycerzes reported it on 1.1.21 using Windows 11 24H2
@Mojobucks reported downgrading from 1.1.15 to 1.1.14 fixed it

Issues mentioning that problem

Strategies to delete that file...

cmd /c del \\.\C:\path\to\nul (@harunurhan)
WSL rm /mnt/c/path/to/nul (Windows: Git Bash auto-detection derives invalid bash.exe path #10871 (comment), @Xenogix )
WinRar's "Delete files after archiving"

This issue appears to be a duplicate of existing open issues. Please check:

Unexpected file named "nul" is repeatedly created after updating OpenCode #11403: Unexpected file named "nul" is repeatedly created after updating OpenCode
nul file generate #11586: nul file generate

These issues describe the same problem with the nul file being created and causing issues on Windows. Consider consolidating the discussion there to help maintainers track the fix.

Happens for me in OpenCode 1.2.1 on Windows 11. Can't delete in PowerShell, but can delete using File Explorer. Requires admin approval to delete.

PS: Claude says this: "This is almost certainly being created by OpenCode (or one of its tools) running on Windows. When code written for Unix tries to redirect output to /dev/null, on Windows that can inadvertently create a literal file named nul in the working directory."

...can delete using File Explorer. Requires admin approval to delete.

Scratch that, it just appears to delete it, but when i hit it F5 it's there again. So either it didn't actually get deleted, or it got re-created immediately? 🤔

Oh, there is a fix. Ignore me...

FYI, you can delete the file using something like this cmd /c del \\.\C:\path\to\nul, for the time being.

It looks like our version of this file contains stdout redirect data, which is possible to read through WSL (cat /mnt/c/path/to/nul)

dir: cannot access '/s': No such file or directory
dir: cannot access '*.dll': No such file or directory

It is also possible to remove it easily with WSL using rm /mnt/c/path/to/nul

Here is what i found with codex:

What’s going wrong

On Windows, opencode often runs commands via Git Bash.
The model sometimes emits Windows‑style redirection like > NUL.
In Git Bash, NUL is treated as a literal filename, so it creates a file named nul (a reserved device name). PowerShell then can’t delete it.

Best fix

Normalize null‑device redirections before executing: if the shell is POSIX (bash/sh), rewrite NUL → /dev/null; if the shell is cmd/PowerShell, rewrite /dev/null → NUL.
Also surface the actual shell in the system prompt so the model doesn’t guess the wrong redirection syntax.

Will see if the fix works locally.
Btw. you can also delete the file with git bash.

I can't delete it using any Windows command, and even DiskGenius returns an error, but in WSL works

I can't delete it using any Windows command, and even DiskGenius returns an error, but in WSL works

try run in cmd:
del "\\?\C:\path to it\nul"

path must be absolute

I ask opencode to remove it and it works. It is annoying.

I tried a lot of commands in WINDOWS PowerShell or CMD, but finally only GitBash rm nul works

for windows users, opencode now uses powershell by default. so there wont be any pipe issues creating the nul files

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Undeletable `nul` file #13369

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Undeletable nul file #13369

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github-actions commented on Feb 12, 2026

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Undeletable `nul` file #13369