R command execution from shell
On Tue, 4 Jan 2011, Duncan Murdoch wrote:
On 04/01/2011 3:21 PM, Sebastien Bihorel wrote:
Dear R-users,
Is there a way I can ask R to execute the "write("hello
world",file="hello.txt")" command directly from the UNIX shell, instead
of having to save this command to a .R file and execute this file with R
CMD BATCH?
Yes. Some versions of R support the -e option on the command line to execute
a particular command. It's not always easy to work out the escapes so your
shell passes all the quotes through... An alternative is to echo the command
into the shell, e.g.
echo 'cat("hello")' | R --slave
(where the outer ' ' are just for bash).
It is marginally preferable to use Rscript in place of 'R --slave'.
I think in all known shells
Rscript -e "write('hello world', file = 'hello.txt')"
will work. (If not, shQuote() will not work for that shell, but this
does work in sh+clones, csh+clones, zsh and Windows' cmd.exe.)
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