And, in addition to the tip from Rui (and similar from Joshua) below, I would advise that there is one good reason not to try doing it in "pure Linux".
The only source (that I know of) in Linux itself for random numbers can be tapped by something like cat /dev/random > filename /dev/random stores noise generated by the timings of system events (keyboard presses, mouse-clicks, disk accesses, interrupts, etc.) after subjecting them to a high-entropy stirring process. See: man random It yields them in the form of random bytes (each of 8 random 0/1 bits) and you would have to devise some means of coverting those onto a form suitable for accessing a directory listing at random. Not a pretty task! There is also the command 'rand' available in the openSSL toolkit, but that still outputs the results in the same format as /dev/random. If you really want to do this outside R, the I would suggest writing a little C program (to be run from the Linux command line). C can do its own random number generation, with results returned as real (double), and then apply these to select at random from the contents of a file generated by something like ls filesdir > filelist.txt and output the random selection. Ted. On 28-Jul-2012 18:00:38 Rui Barradas wrote: > Hello, > > If the files are to be processed in R select a random sample in R. > Using list.files() you can assign a character vector with the filenames > of interest and then sample from that vector. > > ?list.files > filenames <- list.files(path, pattern) > > rand.sampl <- sample(filenames, 45) > > Hope this helps, > > Rui Barradas > > Em 28-07-2012 18:49, Erin Hodgess escreveu: >> Dear R People: >> >> I am using a Linux system in which I have about 3000 files. >> >> I would like to randomly select about 45 of those files to be processed in >> R. >> >> Could I make the selection in R or should I do it in Linux, please? >> >> This is with R-2.15.1. >> >> Thanks, >> erin >> >> > > ______________________________________________ > 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. ------------------------------------------------- E-Mail: (Ted Harding) <ted.hard...@wlandres.net> Date: 28-Jul-2012 Time: 19:32:26 This message was sent by XFMail ______________________________________________ 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.