Because glob() will simply pass-thru anything that doesn't need expansion, otherwise it would lose ordinary filenames. But if the 'option' might have the expandable characters '*' or '?' you will be in danger of losing _those_ options. glob('-f?') returns nothing (usually), though glob('-f') will simply return '-f'.
in reply to Re^2: using wildcard character * in perlscript command line
in thread using wildcard character * in perlscript command line