diff --git a/Userland/Utilities/echo.cpp b/Userland/Utilities/echo.cpp index a70caa9919..72af0f3fab 100644 --- a/Userland/Utilities/echo.cpp +++ b/Userland/Utilities/echo.cpp @@ -9,6 +9,58 @@ #include #include +static char backslash_escaped_char(char c) +{ + switch (c) { + case '\\': + return c; + // `\"` produces `"` with printf(1), but `\"` with echo(1) + case 'a': + return '\a'; + case 'b': + return '\b'; + case 'e': + return '\e'; + case 'f': + return '\f'; + case 'n': + return '\n'; + case 'r': + return '\r'; + case 't': + return '\t'; + case 'v': + return '\v'; + default: + return c; + } +} + +static String interpret_backslash_escapes(String s) +{ + StringBuilder builder; + + for (size_t i = 0; i < s.length();) { + if (char c = s[i++]; c != '\\') { + builder.append(c); + continue; + } + if (i == s.length()) { + // Last character of string is '\' -- output it verbatim. + builder.append('\\'); + } + + char c = s[i++]; + if (c == 'c') // `\c` suppresses further output. + break; + // FIXME: \0ooo, \xHH, \uHHHH, \UHHHHHHHH should produce characters if followed by + // enough digits. + builder.append(backslash_escaped_char(c)); + } + + return builder.build(); +} + int main(int argc, char** argv) { if (pledge("stdio", nullptr) < 0) { @@ -18,13 +70,18 @@ int main(int argc, char** argv) Vector values; bool no_trailing_newline = false; + bool should_interpret_backslash_escapes = false; Core::ArgsParser args_parser; args_parser.add_option(no_trailing_newline, "Do not output a trailing newline", nullptr, 'n'); + args_parser.add_option(should_interpret_backslash_escapes, "Interpret backslash escapes", nullptr, 'e'); args_parser.add_positional_argument(values, "Values to print out", "string", Core::ArgsParser::Required::No); args_parser.parse(argc, argv); - out("{}", String::join(' ', values)); + String output = String::join(' ', values); + if (should_interpret_backslash_escapes) + output = interpret_backslash_escapes(move(output)); + out("{}", output); if (!no_trailing_newline) outln(); return 0;