If you leave out either the HTTP username or password, no authentication will be sent. If you leave out the FTP password, your email address will be supplied as a default password. Refer to RFC1738 for a comprehensive list of unsafe characters. If you do not understand the difference between these notations, or do not know which one to use, just use the plain ordinary format you use with your favorite browser, like Lynx or Netscape . Since Wget uses GNU getopts to process its arguments, every option has a short form and a long form.
Long options are more convenient to remember, but take time to type.
You may freely mix different option styles, or specify options after the command-line arguments. The space between the option accepting an argument and the argument may be omitted. The options that accept comma-separated lists all use the convention that, when presented an empty list, it means to clear it. The command line arguments, sorted alphabetically. Your system administrator may have chosen to compile Wget without debug support.