# [Tex/LaTex] How to show the vertical line between two columns

rulestwo-column

Simply using \twocolumn changes my document to look like this:

-----HEADER----
######   ######
######   ######
######   ######
######   ######
######   ######
######   ######
-----FOOTER----


But I'd like to make the line between two columns visible like this:

-----HEADER----
###### | ######
###### | ######
###### | ######
###### | ######
###### | ######
###### | ######
-----FOOTER----


What command will make the line visible?

Use \setlength{\columnseprule}{0.4pt}.
EDIT: Obviously, you may freely choose the thickness of the column-separating line. I suggested 0.4pt because standard LaTeX uses this value for rules above footnotes and around fboxes.