The knitr package (Xie 2016) is an alternative tool to Sweave based on a different design with more features. This document is not an introduction, but only serves as a placeholder to guide you to the real manuals, which are available on the package website https://yihui.org/knitr/1, and remember to read the help pages of functions in this package. There is a book (Xie 2015) for this package, but it may not be useful to those who prefer digging out information on the web.
Anyway, here is a code chunk that shows you can compile vignettes with knitr as well using R 3.0.x, which supports non-Sweave vignettes:
##  1.545004 1.131897 0.002776 -0.082819 2.409905 -1.396916 1.083896 ##  1.802385 0.627644 -1.241974 -1.485010 -0.979978 -0.378730 0.190003 ##  1.241976 -0.617919 1.056736 0.418370 -0.569578 0.858991
|Estimate||Std. Error||t value||Pr(>|t|)|
The fitted regression equation is \(Y=-17.5791+3.9324x\).