mv command GNU bash

commandline session

$> 1
$echo hello > 1
$cat 1
hello
$ls
1
$mv 1 2
$ls
2
$cat 2
hello
$

http://pluto.infoclub.in/wp-content/uploads/2013/06/mv.c

code section

  while ((c = getopt_long (argc, argv, "bfint:uvS:T", long_options, NULL))
         != -1)
    {
      switch (c)
        {
        case 'b':
          make_backups = true;
          if (optarg)
            version_control_string = optarg;
          break;
        case 'f':
          x.interactive = I_ALWAYS_YES;
          break;
        case 'i':
          x.interactive = I_ASK_USER;
          break;
        case 'n':
          x.interactive = I_ALWAYS_NO;
          break;
        case STRIP_TRAILING_SLASHES_OPTION:
          remove_trailing_slashes = true;
          break;
        case 't':
          if (target_directory)
            error (EXIT_FAILURE, 0, _("multiple target directories specified"));
          else
            {
              struct stat st;
              if (stat (optarg, &st) != 0)
                error (EXIT_FAILURE, errno, _("accessing %s"), quote (optarg));
              if (! S_ISDIR (st.st_mode))
                error (EXIT_FAILURE, 0, _("target %s is not a directory"),
                       quote (optarg));
            }
          target_directory = optarg;
          break;
        case 'T':
          no_target_directory = true;
          break;
        case 'u':
          x.update = true;
          break;
        case 'v':
          x.verbose = true;
          break;
        case 'S':
          make_backups = true;
          backup_suffix_string = optarg;
          break;
         case_GETOPT_HELP_CHAR;
         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
        default:
          usage (EXIT_FAILURE);
        }
    }

http://stackoverflow.com/questions/10606250/macros-like-case-getopt-help-char-risky