function tsprintf($pattern)

Arcanist Technical Documentation ()

Format text for terminal output. This function behaves like sprintf, except that all the normal conversions (like "%s") will be properly escaped, and additional conversions are supported:

%B (Block)
  Escapes text, but preserves tabs and newlines.

%R (Raw String)
  Inserts raw, unescaped text. DANGEROUS!

Particularly, this will escape terminal control characters.