Setting a wrap margin

http://www.fmi.uni-passau.de/archive/doc/unix/unixhelp/Unixhelp/didyou_vi.2.html (Einblicke ins Internet, ~06/1995)

return at the end of every line.

Set the wrapmargin (wm) option to a value greater than 0 (zero). For example:

   set wm=5

In insert mode, text is wrapped five (5) characters from the right margin of the screen and a <RETURN> character is automatically inserted.