kubernetes/staging/src/k8s.io/component-base/term/term.go

// TerminalSize returns the current width and height of the user's terminal. If it isn't a terminal,
// nil is returned. On error, zero values are returned for width and height.
// Usually w must be the stdout of the process. Stderr won't work.
func TerminalSize(w io.Writer) (int, int, error) { … }