This solution worked great on linux, but I am having some issues getting it to work on Windows. I used the following code, but get a "Error in system(command, as.integer(flag), f, stdout, stderr, timeout) character string expected as first argument" error. Any ideas?
```{r dot-ex, engine = "dot", engine.path="C:\\Program Files (x86)\\Graphviz2.38\\bin\\dot.exe", fig.cap = "Funky dot", cache=TRUE}
digraph test123 {
a -> b -> c;
a -> {x y};
b [shape=box];
c [label="hello\nworld",color=blue,fontsize=24,fontname="Palatino-Italic",fontcolor=red,style=filled];
a -> z [label="hi", weight=100];
x -> z [label="multi-line\nlabel"];
edge [style=dashed,color=red];
b -> x;
{rank=same; b x}
}