R – graphviz : dynamically creation of node

Yes, HTML-like labels (<...>) support
tag, using which you can break the lines. E.g.

"A" -> "B"
[label = <1. <br/>
 2. <br/>
 3. <br/>
 4. <br/>
 .... <br/> 
> color="blue" style="dashed"];

These also work when embedding Graphviz in LaTeX, where \n would not.

type: dot -Tps filename.dot -o outfile.ps

If you want to use the dot renderer. There are alternatives like neato and twopi. If graphiz isn't in your path, figure out where it is installed and run it from there.

You can change the output format by varying the value after -T and choosing an appropriate filename extension after -o.

If you're using windows, check out the installed tool called GVEdit, it makes the whole process slightly easier.

Go look at the graphviz site in the section called "User's Guides" for more detail on how to use the tools:

http://www.graphviz.org/documentation/

(See page 27 for output formatting for the dot command, for instance)

http://www.graphviz.org/pdf/dotguide.pdf