center-linecenter-line is an interactive compiled Lisp function in `
text-mode.el'. It is bound to M-o M-s.
(center-line &optional NLINES) Center the line point is on, within the width specified by `fill-column'. This means adjusting the indentation so that it equals the distance between the end of the text and `fill-column'. The argument NLINES says how many lines to center.