Fauxnix
Run Linux-style commands on Windows via deterministic bash→PowerShell translation. No VM, no WSL. MCP server + CLI built for AI agents (Claude Code, Codex, Open…
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No install snippet on purpose. A working MCP config is a command, its arguments and an environment block — the last two are where API keys live, so this catalogue never stores them and cannot publish them. Follow the link above for the authors' own instructions.
Run Linux-style commands on Windows — natively, deterministically, no VM, no WSL.
fauxnix is a bash→PowerShell translation layer built for AI agents. Your agent keeps writing the
bash it already knows (ls -la | grep foo, find . -name '*.ts' | wc -l, kill -9 1234), and
fauxnix deterministically translates each command into PowerShell, executes it natively, and hands
back output that looks like GNU/Linux: ls -l columns, bash-style error messages, coreutils exit
codes, UTF-8/GBK handled automatically.
One-command install for Claude Code · Codex · OpenCode · Kimi Code · Qwen Code, plus any MCP client. 109 translated commands · 400+ automated tests · 253-case differential corpus verified against real GNU coreutils · zero LLM calls at runtime.
Try it now — no install
npx fauxnix-cli@latest "ls -la src | head -3"
npx fauxnix-cli@latest translate "find . -name '*.log' -mtime +7 -delete"
$ fauxnix "ls -la src | head -2"
-rw-r--r-- 1 me me 1204 Aug 16 09:12 ast.ts
-rw-r--r-- 1 me me 8192 Aug 16 09:12 cli.ts
$ fauxnix "cat nope.txt"
cat: nope.txt: No such file or directory # not a PowerShell stack trace
Connect your agent — one command
npm install -g fauxnix-cli
fauxnix install --claude # or --codex / --opencode / --kimi / --qwen
fauxnix doctor # verifies encoding, harness config, and MCP round-trip
Idempotent; prints exactly what changed. Manual configurations below if you prefer to edit config files yourself.
npm package name is
fauxnix-cli(thefauxnixname on npm belongs to an unrelated 2015 websocket library); the installed command isfauxnix. Requires Windows with PowerShell 5.1+ (built-in) and Node.js ≥ 18.
Manual config per harness
Claude Code
claude mcp add fauxnix -- fauxnix mcp
Codex (~/.codex/config.toml or codex mcp add fauxnix -- fauxnix mcp)
[mcp_servers.fauxnix]
command = "fauxnix"
args = ["mcp"]
Note: in non-interactive codex exec mode, MCP tool calls are auto-denied by the approval
layer; pass --dangerously-bypass-approvals-and-sandbox (or run interactively and approve
once).
OpenCode (opencode.json)
{
"mcp": {
"fauxnix": { "type": "local", "command": ["fauxnix", "mcp"] }
}
}
Kimi Code — MCP servers live in a JSON file, not the TOML config: ~/.kimi-code/mcp.json
{
"mcpServers": {
"fauxnix": { "command": "fauxnix", "args": ["mcp"] }
}
}
Qwen Code (~/.qwen/settings.json)
fauxnix install --qwen
The installer preserves the rest of settings.json and writes an absolute Node + package-entry
launcher so Qwen startup does not depend on its working directory or PATH order. See
the Qwen example for the generated JSON shape.
Any MCP client — stdio server: fauxnix mcp. The tool name is bash (override with
FAUXNIX_TOOL_NAME). The tool description already teaches the model the supported subset, so no
system-prompt changes are required.
Copy-paste quickstarts with a 10-command smoke test per harness: docs/examples/
The MCP session persists cwd, environment variables, export/unset, cd -/OLDPWD, and
positional parameters (set -- / $1 / "$@") across tool calls — it behaves like a logged-in
shell, not a stateless exec. $0 is the MCP tool name, not a Windows path.
For workflows whose commands are already known, the MCP server also exposes bash_batch: it
compiles every step before execution, runs the plan atomically in one session, and returns one
structured result per step in a single MCP round trip (stops on first nonzero exit by default).
{
"steps": [
{ "id": "write", "command": "printf 'a\\r\\nb' > data.txt" },
{ "id": "measure", "command": "wc -c data.txt" }
]
}
From the project's README.