另類設定程式參數

  for ( argp = argv+1 ; *argp ; argp++ ) {    if ( **argp == '-' ) {      opt = *argp + 1;      if ( !*opt )usage();      while ( *opt ) {switch ( *opt ) {case 's':/* Use "safe, slow and stupid" code */  stupid = 1;  break;case 'r':/* RAID mode */  raid_mode = 1;  break;case 'f':/* Force install */  force = 1;  break;case 'm':/* Install MBR */  mbr = 1;  break;case 'a':/* Mark this partition active */  setactive = 1;  break;case 'd':  if ( argp[1] )    subdir = *++argp;  break;default:  usage();  break;}opt++;      }    } else {      if ( bootsecfile )usage();      else if ( drive )bootsecfile = *argp;      elsedrive = *argp;    }  }