[R] Interacting with the Operating System

[Julio Sergio]

Is there any way to issue operating system commands and geting back the results, 
in R?

I mean, for instance, in Linux, to execute from R the 'ls' command and getting 
back a list of files in the current directory, or, equivalently, in Windows/DOS, 
the 'dir' command?

I'm not interested in the 'ls' or 'dir' commands it is just an example.

Do you have any comments on this matter?

Thanks,

--Sergio.