Procedural. In many text-processing systems, presentational markup is replaced by procedural markup, which consists of commands indicating how text should be formatted. […] Procedural markup is characteristically associated with batch text formatters, such as nroff/troff and TEX. Word processors like WordStar, however, supplement their presentational editing commands with “dot commands.” For example, they use editing commands to center lines (Ctr1 – OC), but include markup in the files for user-specified page breaks (.pa).