[R] Isolating string containing only file name from complete path

[Ken Termiso]

Hi all,

What I'd like to do is to is to be able to extract a string corresponding to 
only the file name from a string containing the complete path, i.e. from the 
following path string:

"/Users/ken/Desktop/test/runs/file1"

I would like to end up with:

"file1"

This would be most ideally done in a platform-independent way.

Thanks in advance,
-Ken