Legends in R plots

I've just spent about 45 mins trying to get a decent results plot from R. I wanted to include a legend for clarity and this gave me some trouble. It turns out the co-ordinate system was using values from the x and y plot rather than pixels... weird. Happily, for simple plots, there's an easy way to position the legend. From the R man page:

The location may also be specified by setting 'x' to a single
keyword from the list '"bottomright"', '"bottom"', '"bottomleft"',
'"left"', '"topleft"', '"top"', '"topright"', '"right"' and
'"center"'. This places the legend on the inside of the plot frame
at the given location.

So, I ended up with something like this:

R --vanilla --slave <<<"d=read.table('data1.csv', sep=',', header=F);e=read.table('data2.csv', header=F, sep=',');png('results.png');dh=hist(d\$V2, plot=F);eh=hist(e\$V2, plot=F);xlim=range(dh\$mids, eh\$mids);ylim=range(dh\$counts, eh\$counts);plot(dh, main='', xlab='value', col='orange', xlim=xlim, ylim=ylim);plot(eh, col='lightblue', add=T);legend('topright', legend=c('label1', 'label2'), fill=c('orange', 'lightblue'));q()"

Pre-calculating the range for the x and y axes (using the range operators) prevents you from cutting off data from one of the plots.