Latexmk runs LaTeX the correct number of times to resolve cross references,
 etc; it also runs auxiliary programs (bibtex, makeindex if necessary, and
 dvips and/or a previewer as requested). It has a number of other useful
 capabilities, for example to start a previewer and then run latex whenever the
 source files are updated, so that the previewer gives an up-to-date view of
 the document.