# Introduction The `unix:` module provides access to features that only make sense on UNIX-like operating systems, such as Linux, FreeBSD, and macOS. On non-UNIX operating systems, such as MS Windows, this namespace does not exist and `use unix` will fail. Use the [`$platform:is-unix`](platform.html#platformis-unix) variable to determine if this namespace is usable. @elvdoc -ns unix: -dir ../pkg/eval/unix