# os.arch

The `os.arch` attribute is a read-only string identifying the architecture of the running Atmos executable.

## Usage

```python
os.arch
```

Common values are `"amd64"` and `"arm64"`. Values follow Go's architecture names; for example, x86-64 is `"amd64"`.
Read the attribute directly, without parentheses. Environment variables cannot override it.
When Atmos runs under emulation, this describes its executable's architecture, which can differ from the physical CPU.

## Examples

```python
asset = "my-tool-" + os.platform + "-" + os.arch
print(asset)
```

## Related

- [`os.platform`](/functions/automation/os.platform) reports the operating system.
- [`exec.run`](/functions/automation/exec.run) runs a program.