[characters] comma = "string," semi-colon = "string;" equal-sign = "string=" double-quote = "string\"" single-quote = "string'" percent = "string%" tilde = "string~" exclamation-mark = "string!" pipe = "string|" ampersand = "string&" open-bracket = "string(" close-bracket = "string)" [emptystrings] string1 = string2 = NULL string3 = "" string4 = none