This web app quickly adds line numbers to text.

This web app adds line numbers to text, adjusts font-size and line-height, and attempts to wrap lines between 55 and 65 characters (which some research suggests may be ideal for readability). The 1-column tool can highlight a single line (by clicking on a line number) or a range of lines (e.g., "1-2,4,8-10"). The app also generates a share link for your text and highlights.

I'm a teacher. I made this to help adapt text for classroom discussion activities where citation is an important goal (such as Socratic Seminar). Two columns side-by-side with line numbers is also a very useful format for displaying an unmodified text side-by-side with a reduced reading level version (or teacher made paraphrase) of the same text.