diff --git a/qendpoint-cli/bin/hdtDiffCat.bat b/qendpoint-cli/bin/hdtDiffCat.bat
new file mode 100644
index 00000000..981566d1
--- /dev/null
+++ b/qendpoint-cli/bin/hdtDiffCat.bat
@@ -0,0 +1,5 @@
+@echo off
+
+call "%~dp0\javaenv.bat"
+
+"%JAVACMD%" %JAVAOPTIONS% -classpath %~dp0\..\lib\* com.the_qa_company.qendpoint.core.tools.HDTDiffCat %*
diff --git a/qendpoint-cli/bin/hdtDiffCat.ps1 b/qendpoint-cli/bin/hdtDiffCat.ps1
new file mode 100644
index 00000000..ede22807
--- /dev/null
+++ b/qendpoint-cli/bin/hdtDiffCat.ps1
@@ -0,0 +1,28 @@
+param(
+    [Parameter()]
+    [String]
+    $options,
+    [Parameter()]
+    [String]
+    $config,
+    [Parameter()]
+    [String]
+    $diff,
+    [Parameter()]
+    [Switch]
+    $index,
+    [Parameter()]
+    [Switch]
+    $version,
+    [Parameter()]
+    [Switch]
+    $quiet,
+    [Parameter()]
+    [Switch]
+    $color,
+    [Parameter(ValueFromRemainingArguments, Position = 0)]
+    [string[]]
+    $OtherParams
+)
+
+& "$(Get-Item $PSScriptRoot)/javaenv.ps1" "com.the_qa_company.qendpoint.core.tools.HDTDiffCat" -RequiredParameters $PSBoundParameters
diff --git a/qendpoint-cli/bin/hdtDiffCat.sh b/qendpoint-cli/bin/hdtDiffCat.sh
new file mode 100644
index 00000000..5fe3eafa
--- /dev/null
+++ b/qendpoint-cli/bin/hdtDiffCat.sh
@@ -0,0 +1,10 @@
+#!/bin/bash
+
+source `dirname $0`/javaenv.sh
+
+#export MAVEN_OPTS="-Xmx6g"
+#mvn exec:java -Dexec.mainClass="com.the_qa_company.qendpoint.core.tools.HDTDiffCat" -Dexec.args="$*"
+
+$JAVA $JAVA_OPTIONS -cp $CP:$CLASSPATH com.the_qa_company.qendpoint.core.tools.HDTDiffCat $*
+
+exit $?
diff --git a/qendpoint-core/src/main/java/com/the_qa_company/qendpoint/core/tools/HDTDiffCat.java b/qendpoint-core/src/main/java/com/the_qa_company/qendpoint/core/tools/HDTDiffCat.java
new file mode 100644
index 00000000..744bdc52
--- /dev/null
+++ b/qendpoint-core/src/main/java/com/the_qa_company/qendpoint/core/tools/HDTDiffCat.java
@@ -0,0 +1,197 @@
+package com.the_qa_company.qendpoint.core.tools;
+
+import com.beust.jcommander.JCommander;
+import com.beust.jcommander.Parameter;
+import com.beust.jcommander.internal.Lists;
+import com.the_qa_company.qendpoint.core.compact.bitmap.Bitmap64Big;
+import com.the_qa_company.qendpoint.core.enums.RDFNotation;
+import com.the_qa_company.qendpoint.core.exceptions.NotFoundException;
+import com.the_qa_company.qendpoint.core.exceptions.ParserException;
+import com.the_qa_company.qendpoint.core.hdt.HDT;
+import com.the_qa_company.qendpoint.core.hdt.HDTManager;
+import com.the_qa_company.qendpoint.core.hdt.HDTVersion;
+import com.the_qa_company.qendpoint.core.listener.MultiThreadListener;
+import com.the_qa_company.qendpoint.core.options.HDTOptions;
+import com.the_qa_company.qendpoint.core.options.HDTOptionsKeys;
+import com.the_qa_company.qendpoint.core.rdf.RDFParserCallback;
+import com.the_qa_company.qendpoint.core.rdf.RDFParserFactory;
+import com.the_qa_company.qendpoint.core.triples.IteratorTripleString;
+import com.the_qa_company.qendpoint.core.util.StopWatch;
+import com.the_qa_company.qendpoint.core.util.io.Closer;
+import com.the_qa_company.qendpoint.core.util.listener.ColorTool;
+import com.the_qa_company.qendpoint.core.util.listener.MultiThreadListenerConsole;
+import org.apache.commons.io.FileUtils;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class HDTDiffCat {
+
+	private ColorTool colorTool;
+
+	@Parameter(description = "<input HDTs>+ <output HDT>")
+	public List<String> parameters = Lists.newArrayList();
+
+	@Parameter(names = "-options", description = "HDT Conversion options (override those of config file)")
+	public String options;
+
+	@Parameter(names = "-config", description = "Conversion config file")
+	public String configFile;
+
+	@Parameter(names = "-diff", description = "File to use to do the diff")
+	public String diff;
+
+	@Parameter(names = "-index", description = "Generate also external indices to solve all queries")
+	public boolean generateIndex;
+
+	@Parameter(names = "-version", description = "Prints the HDT version number")
+	public static boolean showVersion;
+
+	@Parameter(names = "-quiet", description = "Do not show progress of the conversion")
+	public boolean quiet;
+
+	@Parameter(names = "-color", description = "Print using color (if available)")
+	public boolean color;
+
+	private HDT diffcat(String location, HDTOptions spec, MultiThreadListener listener)
+			throws IOException, ParserException, NotFoundException {
+		List<String> inputs = parameters.subList(0, parameters.size() - 1);
+
+		if (diff == null || diff.isEmpty()) {
+			return HDTManager.catHDT(inputs, spec, listener);
+		}
+
+		RDFNotation type = RDFNotation.guess(diff);
+
+		Bitmap64Big[] bms = new Bitmap64Big[inputs.size()];
+		HDT[] inputsMap = new HDT[inputs.size()];
+
+		try {
+			for (int i = 0; i < bms.length; i++) {
+				inputsMap[i] = HDTManager.mapHDT(inputs.get(i));
+				bms[i] = Bitmap64Big.memory(inputsMap[i].getTriples().getNumberOfElements());
+			}
+
+			RDFParserCallback.RDFCallback callback = ((triple, pos) -> {
+				for (int i = 0; i < inputsMap.length; i++) {
+					IteratorTripleString find;
+					try {
+						find = inputsMap[i].search(triple);
+					} catch (NotFoundException e) {
+						throw new RuntimeException(e);
+					}
+
+					if (find.hasNext()) {
+						find.next();
+						bms[i].set(find.getLastTriplePosition(), true); // delete
+																		// it
+					}
+
+				}
+			});
+
+			if (type == RDFNotation.HDT) {
+				try (HDT diffHDT = HDTManager.mapHDT(diff)) {
+					IteratorTripleString it = diffHDT.searchAll();
+					while (it.hasNext()) {
+						callback.processTriple(it.next(), 0);
+					}
+				}
+			} else {
+				RDFParserCallback parser = RDFParserFactory.getParserCallback(type, spec);
+				parser.doParse(diff, "", type, true, callback);
+			}
+		} catch (Throwable t) {
+			try {
+				Closer.closeSingle(inputsMap);
+			} catch (Throwable t2) {
+				t.addSuppressed(t2);
+			}
+			throw t;
+		}
+		Closer.closeSingle(inputsMap);
+
+		return HDTManager.diffBitCatHDT(inputs, List.of(bms), spec, listener);
+	}
+
+	public void execute() throws IOException, ParserException, NotFoundException {
+		HDTOptions spec;
+		if (configFile != null) {
+			spec = HDTOptions.readFromFile(configFile);
+		} else {
+			spec = HDTOptions.of();
+		}
+		if (options != null) {
+			spec.setOptions(options);
+		}
+
+		String hdtOutput = parameters.get(parameters.size() - 1);
+		File file = new File(hdtOutput);
+
+		String locationOpt = spec.get(HDTOptionsKeys.HDTCAT_LOCATION);
+
+		if (locationOpt == null) {
+			locationOpt = file.getAbsolutePath() + "_tmp";
+			spec.set(HDTOptionsKeys.HDTCAT_LOCATION, locationOpt);
+		}
+
+		File theDir = new File(locationOpt);
+		Files.createDirectories(theDir.toPath());
+		String location = theDir.getAbsolutePath() + "/";
+
+		MultiThreadListener listenerConsole = !quiet ? new MultiThreadListenerConsole(color) : null;
+		StopWatch startCat = new StopWatch();
+		try (HDT hdt = diffcat(location, spec, listenerConsole)) {
+			colorTool.logValue("Files catdiff in ...... ", startCat.stopAndShow(), true);
+			assert hdt != null;
+			// Show Basic stats
+			if (!quiet) {
+				colorTool.logValue("Total Triples ......... ", String.valueOf(hdt.getTriples().getNumberOfElements()));
+				colorTool.logValue("Different subjects .... ", String.valueOf(hdt.getDictionary().getNsubjects()));
+				colorTool.logValue("Different predicates .. ", String.valueOf(hdt.getDictionary().getNpredicates()));
+				colorTool.logValue("Different objects ..... ", String.valueOf(hdt.getDictionary().getNobjects()));
+				colorTool.logValue("Common Subject/Object . ", String.valueOf(hdt.getDictionary().getNshared()));
+			}
+
+			// Dump to HDT file
+			StopWatch sw = new StopWatch();
+			hdt.saveToHDT(hdtOutput, listenerConsole);
+			colorTool.logValue("HDT saved to file in .. ", sw.stopAndShow());
+			Files.deleteIfExists(Path.of(location + "dictionary"));
+			Files.deleteIfExists(Path.of(location + "triples"));
+			FileUtils.deleteDirectory(theDir);
+
+			// Generate index and dump it to .hdt.index file
+			sw.reset();
+			if (generateIndex) {
+				HDTManager.indexedHDT(hdt, listenerConsole);
+				colorTool.logValue("Index generated and saved in ", sw.stopAndShow());
+			}
+		}
+	}
+
+	public static void main(String[] args) throws Throwable {
+		HDTDiffCat diffcat = new HDTDiffCat();
+		JCommander com = new JCommander(diffcat);
+		com.parse(args);
+		com.setProgramName("hdtDiffCat");
+		diffcat.colorTool = new ColorTool(diffcat.color, diffcat.quiet);
+
+		if (showVersion) {
+			diffcat.colorTool.log(HDTVersion.get_version_string("."));
+			System.exit(0);
+		} else if (diffcat.parameters.size() < 2) {
+			com.usage();
+			System.exit(1);
+		}
+
+		diffcat.colorTool.log("DiffCat "
+				+ diffcat.parameters.stream().limit(diffcat.parameters.size() - 1).collect(Collectors.joining(", "))
+				+ " to " + diffcat.parameters.get(diffcat.parameters.size() - 1));
+		diffcat.execute();
+	}
+}