Plot of multiple data sets

Hello !


There is something quite simple I want to do with R but I found nowhere in the help how to do it.
I just want to plot data which are in a matrix, every column being a data set and having the same
x-axis (just an index).

So for example if I have a 50 x 6 matrix I want 6 set of points on the same plot.

I tried
plot,new()
plot(MATRIX[,1])
plot(MATRIX[,2])
...

but it replaces the previous plot each time.