1  /* kbFile.c
   2     This example shows how to save keyboard input to a disk file.
   3     System calls used in this program:
   4      . write(), read(), open(), close(), exit().
   5  */
     
   6  #include <stdio.h>
   7  #include <fcntl.h>
   8  #include <unistd.h>
   9  #include <sys/stat.h> 
     
  10  #define FMODE  (S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH)
     
  11  main()
  12  {
  13     char buf[BUFSIZ];
  14     char PROMPT1[] = "Please enter output filename >> "; 
  15     char PROMPT2[] = "Please enter input, to be terminated by <ctrl-d>\n";
  16     char ERR[] = "Can't open output file\n";
  17     int fd;
  18     ssize_t nread;
     
  19     write(STDOUT_FILENO, PROMPT1, strlen(PROMPT1)); /* write to stdout */
  20     nread = read(STDIN_FILENO, buf, BUFSIZ);        /* read from stdin */
  21     buf[nread-1] = '\0';                   /* strip \n & NULL-terminate buf */
     
  22     if ((fd = open(buf, O_WRONLY | O_CREAT | O_TRUNC, FMODE)) == -1) {
  23         write(STDERR_FILENO, ERR, strlen(ERR));    /* write to stderr */
  24         return(1);
  25     }
     
  26     write(STDOUT_FILENO, PROMPT2, strlen(PROMPT2));
  27     while (1) {
  28         nread = read(STDIN_FILENO, buf, BUFSIZ);  /* count char's read */
  29         if (nread > 0)          
  30             write(fd, buf, nread);                /* save to file */
  31         else
  32            break;                         /* EOF detected - assume no error */
  33     }
  34     close(fd);                            /* close output file */
  35     exit(0);                              /* cool */
  36  }