type Os interface {
FindProcess(pid int) (*os.Process, error)
Hostname() (name string, err error)
Expand(s string, mapping func(string) string) string
Clearenv()
Environ() []string
Chtimes(name string, atime time.Time, mtime time.Time) error
MkdirAll(path string, perm os.FileMode) error
Exit(code int)
Fictional(lol ...string)
}