How can I draw a vertical line on every page of a document?

Question

I want to draw a vertical line on the left of every odd-numbered page and on the right of every even-numbered page in a document. Is there a preamble to do this?

Answer 1

This draws a line 0.5\marginparsep to the left or right of the text area.

\documentclass{report}
\usepackage{everypage}
\usepackage{tikzpagenodes}
\usetikzlibrary{calc}
\usepackage{lipsum}% MWE only

\AddEverypageHook{\tikz[remember picture,overlay]{%
  \ifodd\value{page}\draw ($(current page text area.north west)+(-0.5\marginparsep,0pt)$)
    -- ($(current page text area.south west)+(-0.5\marginparsep,0pt)$);
  \else\draw ($(current page text area.north east)+(0.5\marginparsep,0pt)$)
    -- ($(current page text area.south east)+(0.5\marginparsep,0pt)$);
  \fi}}

\begin{document}
\lipsum [1-16]
\end{document}