Printing a single "\" character

Hi,
I have a small R question: how to print a single "\" character? I have the
following results:

print("\") does not work

print("\\")

[1] "\\"

Use cat("\\").

I need to make the following substitution as well, but it does not work
either:

sub("_","\_","g_g")

[1] "g_g"

Use
   sub("_","\\\\_","g_g")

If you print() the result it will look as though it has a double \, but 
that's an optical illusion. cat() will show it correctly with a single \ 
(and nchar() will confirm that it has 4 characters).

 	-thomas