# engine.TmuxCommandResult

- **Module:** engine
- **Package:** libtmux
- **Language:** TypeScript
- **Kind:** typealias
- **Source:** https://github.com/libtmux/libtmux-ts/blob/46cccfef2a546de55ce8b308249b8c76339089a0/packages/libtmux/src/engine.ts#L116
- **Page:** https://libtmux.org/en/ts/latest/reference/engine-tmuxcommandresult/

```ts
type TmuxCommandResult = {
  readonly cmd: readonly string[];
  readonly exitCode: number;
  readonly signal: string | null;
  readonly stderr: Uint8Array;
  readonly stdout: Uint8Array;
}
```

What an engine reports back: the process's own exit, not tmux's opinion of it.

A `returncode` of zero and a `signal` of [`null`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/null) together mean tmux ran and
answered; either one set means it did not finish, and `stderr` says why.