Thanks everybody for your help (and sorry to be silent : no network today morning), I think I will first try the solution of Greg Snow-2 or the one of Thierry (because they gave examples of script - as a newbye it is very important to me).
I'm also interested in the solutions proposed by Uwe and Gabor, but I'm not familiar with environment variables (I will try ?Sys.getenv) and I have no idea how to edit .rnw file with R (but as it seems that everything is possible with R, so why not). Again thank you, And if you have further advices to help me writing scripts (in R for example), do not hesitate. Have a nice day, Ptit Bleu. PS : I'm using R version 2.5.1 (2007-06-27) with XP -- View this message in context: http://www.nabble.com/Sweave-%3A-change-value-in-rnw-file-to-generate-multiple-%22single%22-reports---tp14256204p14272449.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.