Scoping x and y limits simultaneously

[Fritz Sonnichsen]

I am processing a rather large dataset and want to create and zoom 
various plots. I am easily able to zoom the x axis using the axis([x1 
x2]) type command. However when I do this I need to re-normalize the y 
limits to fill the plot.
      At present I have a rather lengthy script that finds the min and 
max y values within the new range , retrieve their indices,  and then 
divides all the y values.

However I was thinking there is a better way to do this as such:

data=load('C:address@hidden');
plot(data(:,1),data(:,2));
axis([20 30]);
ylim auto

This does not work. The "auto" mandate scopes the y across the complete 
range, not just the scoped down range.

Is there a way to do this without my scripts?

thanks
Fritz