19.16 Truncation of Lines

As an alternative to continuation, Emacs can display long lines by truncation. This means that all the characters that do not fit in the width of the screen or window do not appear at all. On graphical displays, a small straight arrow in the fringe indicates truncation at either end of the line. On text-only terminals, ‘$’ appears in the first column when there is text truncated to the left, and in the last column when there is text truncated to the right.

Horizontal scrolling automatically causes line truncation (see section Horizontal Scrolling). You can explicitly enable line truncation for a particular buffer with the command M-x toggle-truncate-lines. This works by locally changing the variable truncate-lines. If that variable is non-nil, long lines are truncated; if it is nil, they are continued onto multiple screen lines. Setting the variable truncate-lines in any way makes it local to the current buffer; until that time, the default value is in effect. The default value is normally nil.

If the variable truncate-partial-width-windows is non-nil, it forces truncation rather than continuation in any window less than the full width of the screen or frame, regardless of the value of truncate-lines. For information about side-by-side windows, see Splitting Windows. See also (elisp)Display section `Display' in The Emacs Lisp Reference Manual.

If the variable overflow-newline-into-fringe is non-nil on a graphical display, then Emacs does not continue or truncate a line which is exactly as wide as the window. Instead, the newline overflows into the right fringe, and the cursor appears in the fringe when positioned on that newline.