Clean escapes the UTF8 encoded string provided as input so it is safe to print on a unix terminal.

CleanBytes is a wrapper around Clean to work on byte slices instead of strings.

Writer can be used to write data to the underlying io.Writer, while transparently sanitizing it.

Taken from unexported data at golang.org/x/crypto/ssh/terminal and expanded with data at github.com/keybase/client/go/client:color.go.