[R] calling files of commands in R

[Anna H. Pryor]

Please excuse me if this is a very basic question and I am just 
misunderstanding the basic structure of R.

Right now, I am writing everything in a buffer (emacs) and then copying it 
into R when it is correct.  Is there a way to save a file of commands and 
then just type the file name or something in R and have the commands executed 
within R?

Anna