vos

type Env interface {
	Environ() []string

	Getenv(key string) string
	Getwd() (string, error)
	Stdout() io.Writer
	Stderr() io.Writer
	Stdin() io.Reader

	Setenv(key, value string) error
	Setwd(dir string) error
	Setstdout(io.Writer)
	Setstderr(io.Writer)
	Setstdin(io.Reader)
}