I know you can do it with littler, and after some inspection, is actually thanks to dotcop. So you would need dotcop to flag arguments with Rscript.
alternatively, if you want to have some fun and don't care about ending up with a huge mess, you can DIY.
My example is a nonsensical one, and I just wrote it now, as I don't like it much, but as an example if you save the following code in, i.e. example.R
args <- commandArgs(trailingOnly = TRUE)
dist <- match.fun(strsplit(grep('--distribution*', args, value = TRUE), split = '=')[[1]][[2]])
n <- as.numeric(strsplit(grep('--size*', args, value = TRUE), split = '=')[[1]][[2]])
file.out <- match.fun(strsplit(grep('--format*', args, value = TRUE), split = '=')[[1]][[2]])
file.out()
plot(density(dist(n)))
dev.off()
Then you can just call it from the command lines specifying with statistical distribution you wanna randomly generate (--distriburion), its sample size (--size), and the plot format (--format). It will save it to the current directory
Rscript example.R --distribution=rexp --size=200 --format=jpeg
and will print a a density plot with the desired specs. Do it at your own risk 