--- a/src/GrepHandler.h	Mon Dec 10 15:19:14 2018 +0100
+++ b/src/GrepHandler.h	Mon Dec 10 21:17:26 2018 +0100
@@ -33,35 +33,84 @@
 
 #include <relpipe/writer/Factory.h>
 
+#include <relpipe/cli/RelpipeCLIException.h>
+
 namespace relpipe {
 namespace tr {
 namespace grep {
 
+using namespace std;
 using namespace relpipe;
 using namespace relpipe::reader;
 using namespace relpipe::reader::handlers;
 
 class GrepHandler : public RelationalReaderStringHadler {
 private:
-	std::shared_ptr<writer::RelationalWriter> relationalWriter;
+	shared_ptr<writer::RelationalWriter> relationalWriter;
+
+	wregex relationNameRegEx;
+	wregex attributeNameRegEx;
+	wregex searchRegEx;
+
+	vector<boolean_t> currentSearchableAttributes;
+	vector<string_t> currentRecord;
+	integer_t currentAttributeIndex = 0;
+	boolean_t includeCurrentRecord = false;
+	boolean_t filterCurrentRelation = false;
+
 public:
 
-	GrepHandler(std::ostream& output) {
+	GrepHandler(ostream& output, const vector<string_t>& arguments) {
 		relationalWriter.reset(writer::Factory::create(output));
+
+		if (arguments.size() == 3) {
+			relationNameRegEx = wregex(arguments[0]);
+			attributeNameRegEx = wregex(arguments[1]);
+			searchRegEx = wregex(arguments[2]);
+		} else {
+			throw cli::RelpipeCLIException(L"Usage: relpipe-tr-grep <relationNameRegExp> <attributeNameRegExp> <searchRegExp>", cli::CLI::EXIT_CODE_UNKNOWN_COMMAND);
+		}
 	}
 
-	void startRelation(string_t name, std::vector<AttributeMetadata> attributes) override {
+	void startRelation(string_t name, vector<AttributeMetadata> attributes) override {
 		// TODO: move to a reusable method (or use same metadata on both reader and writer side?)
-		std::vector<writer::AttributeMetadata> writerMetadata;
+		vector<writer::AttributeMetadata> writerMetadata;
 		for (AttributeMetadata readerMetadata : attributes) {
 			writerMetadata.push_back({readerMetadata.getAttributeName(), relationalWriter->toTypeId(readerMetadata.getTypeName())});
 		}
-		
+
+
+		currentRecord.resize(attributes.size());
+		currentSearchableAttributes.resize(attributes.size(), false);
+		filterCurrentRelation = regex_match(name, relationNameRegEx);
+		if (filterCurrentRelation) {
+			for (int i = 0; i < currentSearchableAttributes.size(); i++) {
+				currentSearchableAttributes[i] = regex_match(attributes[i].getAttributeName(), attributeNameRegEx);
+			}
+		}
+
 		relationalWriter->startRelation(name, writerMetadata, true);
 	}
 
 	void attribute(const string_t& value) override {
-		relationalWriter->writeAttribute(value);
+		if (filterCurrentRelation) {
+			currentRecord[currentAttributeIndex] = value;
+
+			if (currentSearchableAttributes[currentAttributeIndex]) {
+				includeCurrentRecord |= regex_search(value, searchRegEx);
+			}
+
+			currentAttributeIndex++;
+
+			if (currentAttributeIndex > 0 && currentAttributeIndex % currentSearchableAttributes.size() == 0) {
+				if (includeCurrentRecord) for (string_t v : currentRecord) relationalWriter->writeAttribute(v);
+				includeCurrentRecord = false;
+			}
+
+			currentAttributeIndex = currentAttributeIndex % currentSearchableAttributes.size();
+		} else {
+			relationalWriter->writeAttribute(value);
+		}
 	}
 
 	void endOfPipe() {

--- a/src/relpipe-tr-grep.cpp	Mon Dec 10 15:19:14 2018 +0100
+++ b/src/relpipe-tr-grep.cpp	Mon Dec 10 21:17:26 2018 +0100
@@ -42,22 +42,22 @@
 	setlocale(LC_ALL, "");
 	CLI::untieStdIO();
 	CLI cli(argc, argv);
-	
+
 	int resultCode = CLI::EXIT_CODE_UNEXPECTED_ERROR;
 
 	try {
 		std::shared_ptr<RelationalReader> reader(Factory::create(std::cin));
-		GrepHandler handler(std::cout);
+		GrepHandler handler(std::cout, cli.arguments());
 		reader->addHandler(&handler);
 		reader->process();
 
 		resultCode = CLI::EXIT_CODE_SUCCESS;
 
-	} catch (RelpipeCLIException e) {
+	} catch (RelpipeCLIException& e) {
 		fwprintf(stderr, L"Caught CLI exception: %ls\n", e.getMessge().c_str());
 		fwprintf(stderr, L"Debug: Input stream: eof=%ls, lastRead=%d\n", (cin.eof() ? L"true" : L"false"), cin.gcount());
 		resultCode = e.getExitCode();
-	} catch (RelpipeReaderException e) {
+	} catch (RelpipeReaderException& e) {
 		fwprintf(stderr, L"Caught Reader exception: %ls\n", e.getMessge().c_str());
 		fwprintf(stderr, L"Debug: Input stream: eof=%ls, lastRead=%d\n", (cin.eof() ? L"true" : L"false"), cin.gcount());
 		resultCode = CLI::EXIT_CODE_DATA_ERROR;