exec

type Cmd interface {
	// CombinedOutput runs the command and returns its combined standard output
	// and standard error.  This follows the pattern of package os/exec.
	CombinedOutput() ([]byte, error)
}

type ExitError interface {
	String() string
	Error() string
	Exited() bool
	ExitStatus() int
}

type Interface interface {
	// Command returns a Cmd instance which can be used to run a single command.
	// This follows the pattern of package os/exec.
	Command(cmd string, args ...string) Cmd
}