look for difference b/w files

Kevin,

  I am using Mac OX 10.3 and I have Emacs+ESS installed.

  I try to find difference b/w two script files. I appreciate it if  
you  could kindly tell me how do I achieve it, either by some kind  
of Mac  applications or command in R. I did see someone running a  
statement on  Unix.

just for completeness, there is a very nice utility in Developer/ 
Applications/Utilities called "FileMerge". It is much nicer than diff  
and also allows you to create a resulting file by specifying which  
parts you want from which file. It is too intuitive and easy to use  
for Emacs users but I though I'll mention it anyway ;).

Cheers,
Simon