-@item @@@var{file}
-Read command-line options from @var{file}. The options read are
-inserted in place of the original @@@var{file} option. If @var{file}
-does not exist, or cannot be read, then the option will be treated
-literally, and not removed.
-
-Options in @var{file} are separated by whitespace. A whitespace
-character may be included in an option by surrounding the entire
-option in either single or double quotes. Any character (including a
-backslash) may be included by prefixing the character to be included
-character with a backslash. The @var{file} may itself contain
-additional @@@var{file} options; any such options will be processed
-recursively.