BEGIN { c[" "] = "\" \"" c["\a"] = "\\a" c["\b"] = "\\b" c["\f"] = "\\f" c["\n"] = "\\n" c["\r"] = "\\r" c["\t"] = "\\t" c["\v"] = "\\v" sort = "LC_ALL=C sort" for (i in c) printf("%s %s [[:space:]]\n", c[i], i ~ /[[:space:]]/ ? "~" : "!~") | sort for (i in c) printf("%s %s [[:blank:]]\n", c[i], i ~ /[[:blank:]]/ ? "~" : "!~") | sort close(sort) }