Unix in a Nutshell, 4th Edition

Name

split

Synopsis

[count] sp [+num] [filename]

Split the current window and load filename in the new window, or the same buffer in both windows if no file is specified. Make the new window count lines high, or if count is not specified, split the window into equal parts. With the +n argument, begin editing on line num. num may also be a pattern of the form /pattern. {vim}