special characters are: period. underscore. back tick or grave accent. tilde. exclamation mark. at sign. number sign or hash or pound sign. dollar sign. caret. asterisk. left parenthesis. right parenthesis. equals to. colon. semicolon. comma. question mark. left curly brace. right curly brace. left square bracket. right square bracket. vertical bar. hyphen. ampersand. plus sign. backslash. slash. less than. greater than. quotation mark.