> For the complete documentation index, see [llms.txt](https://osl.mistium.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://osl.mistium.com/standard-library/system/sys.md).

# sys

Use `sys` for process arguments, environment variables, working directories, process IDs, shell commands, and opening URLs.

```osl
import "std:sys"
```

## Example

```osl
import "std:sys"

log sys.getArgs()
log sys.getCwd()
```

## API reference

### `sys`

| Method                                   | Returns   | Notes                                                                                                                                  |
| ---------------------------------------- | --------- | -------------------------------------------------------------------------------------------------------------------------------------- |
| `sys.getArgs()`                          | `array`   | Returns args.                                                                                                                          |
| `sys.getEnv(key: string)`                | `string`  | Returns env.                                                                                                                           |
| `sys.setEnv(key: string, value: string)` | `boolean` | Sets env.                                                                                                                              |
| `sys.unsetEnv(key: string)`              | `boolean` | Removes an environment variable.                                                                                                       |
| `sys.getCwd()`                           | `string`  | Returns cwd.                                                                                                                           |
| `sys.chdir(path: string)`                | `boolean` |                                                                                                                                        |
| `sys.getPid()`                           | `number`  | Returns pid.                                                                                                                           |
| `sys.getPpid()`                          | `number`  | Returns ppid.                                                                                                                          |
| `sys.getUid()`                           | `number`  | Returns uid.                                                                                                                           |
| `sys.getGid()`                           | `number`  | Returns gid.                                                                                                                           |
| `sys.getUsername()`                      | `string`  | Returns the current user's name.                                                                                                       |
| `sys.getHomeDir()`                       | `string`  | Returns the current user's home directory.                                                                                             |
| `sys.cmd(cmd: string, ...args: string)`  | `string`  | Runs a command with arguments forwarded directly. Returns stdout up to 16 MiB, or an empty string on command failure or excess output. |
| `sys.getExecutablePath()`                | `string`  | Returns executable path.                                                                                                               |
| `sys.openURL(url: string)`               | `boolean` | Opens a validated URL using the exact platform command.                                                                                |

## Notes

* Prefer `import "std:sys"`; the older `import "osl/sys"` spelling remains supported.

## Behavior and limits

Environment and working-directory changes are safe across threads. User and group ID `0` is reported rather than treated as missing. `openURL` rejects malformed URLs and unsupported schemes.