title: How to append a variable to a .mat file?
body: <p>If I already have a <code>.mat</code> file with the variables <code>x</code> and <code>y</code>, is there a way to use the <code>save</code> command to add another variable <code>z</code> to the <code>.mat</code> file without having to explicitly state the variables <code>x</code> and <code>y</code> in the save command? </p>