Time for action – redefining the footnote line

We will use \renewcommand to override the default \footnoterule command:

1. Take the previous example and add the following lines to the preamble:

   \renewcommand{\footnoterule}
       {\noindent\smash{\rule[3pt]{\textwidth}{0.4pt}}}

2. Typeset and see how the line has changed:

   

What just happened?

Remember the definition of \newcommand—here it's analogous. The existing command \footnoterule will be replaced by a new definition that we wrote in the second line. The command \rule[raising]{width}{height} draws a line, here 0.4 pt thick, and as wide as the text, raised a bit by 3 pt. Through the command \smash, we let our line pretend to have a height and a depth of zero, so it's occupying no vertical space at all. This way, the page balancing will not be affected. You already know \noindent, which avoids the paragraph indentation.

If you want to omit that line completely, you just need to write:

\renewcommand{\footnoterule}{}

Now the command is defined to do nothing...