#include <unistd.h>#include <sys/stat.h>#include <fcntl.h>int main(){    char c;     int in, out;    in = open("file.in", O_RDONLY);     out = open("file.out", O_WRONLY|O_CREAT, S_IRUSR|S_IWUSR);    while(read(in,&c,1) == 1)        write(out,&c,1);    exit(0);}