Re: file size different from ls to du

From: Leo Bicknell (bicknell_at_ufp.org)
Date: 07/29/03

  • Next message: Joshua Oreman: "Re: file size different from ls to du" 
    Date: Tue, 29 Jul 2003 11:53:55 -0400
To: freebsd-hackers@freebsd.org

    In a message written on Tue, Jul 29, 2003 at 05:27:14PM +0200, Bogdan TARU wrote:
    > I have tried to create some files of myself, with 'spaces' in them
    > (holes?), but they don't act like this. So could you please explain what
    > 'sparse' means, and the 'trick' to create them?

    % cat sparse.c

    #include <sys/types.h>
    #include <sys/uio.h>
    #include <fcntl.h>
    #include <unistd.h>

    int main(void) {
        int fd;

        fd = open("sparse-file", O_RDWR|O_CREAT);

        lseek(fd, 1024*1024*1024, SEEK_SET);

        write(fd, "0123456789", 10);

        close(fd);
    }
    % cc -o sparse sparse.c
    % ./sparse
    % ls -lag sparse-file
    -r-xr----- 1 bicknell bicknell 1073741834 Jul 29 11:52 sparse-file*
    % du -k sparse-file
    48 sparse-file 

    -- 
       Leo Bicknell - bicknell@ufp.org - CCIE 3440
        PGP keys at http://www.ufp.org/~bicknell/
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  • Next message: Joshua Oreman: "Re: file size different from ls to du"