[R] Multiple barplots on the same axis

[Andre Nathan]

Hi

R newbie here :)

I need to plot 3 barplots in the same axis, something like

   |
   |      _            _            _
   |     | | _        | | _        | | _ 
   |   _ | || |     _ | || |     _ | || |
   |  | || || |    | || || |    | || || |
  -+-----------------------------------------
   |     v1           v2           v3


Is there any documentation describing how to achieve that, and what data
file layout would make the job easier?

Thanks in advance,
Andre