Clipboard under Linux/Unix

This may be a trivial question, but I don't find the answer in R online
help. Under Windows, I can copy/paste to the clipboard using
readClipboard()/writeClipboard(), or something like cat(..., file =
"clipboard"). Are there equivalent function for other platforms?

No.  There is not necessarily even the equivalent of a clipboard; I am 
typing this in a terminal session on a remote computer that has no access 
to the clipboard on my local windowing system (nor even to my local 
display: for performance reasons the X11 connection is not forwarded, 
and even if it were, I do the same thing from my Windows laptop and 
there Exceed and Windows have separate clipboards in different formats).

Please do use R-devel and not R-help for programming questions: see the 
posting guide.

Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595