diff --git a/pom.xml b/pom.xml
index fd50f5f..34a3bd2 100644
--- a/pom.xml
+++ b/pom.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="UTF-8"?>
+<?xml version="1.0" encoding="UTF-8" ?>
 <!--
 
     Copyright (C) 2019-2020 Philip Helger
@@ -93,6 +93,11 @@
         <type>pom</type>
         <scope>import</scope>
       </dependency>
+      <dependency>
+        <groupId>info.picocli</groupId>
+        <artifactId>picocli</artifactId>
+        <version>4.1.4</version>
+      </dependency>
     </dependencies>
   </dependencyManagement>
 
@@ -125,7 +130,11 @@
       <groupId>com.helger</groupId>
       <artifactId>ph-ubl22</artifactId>
     </dependency>
-
+    <dependency>
+      <groupId>info.picocli</groupId>
+      <artifactId>picocli</artifactId>
+      <version>4.1.4</version>
+    </dependency>
     <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>
@@ -134,7 +143,7 @@
     <dependency>
       <groupId>org.slf4j</groupId>
       <artifactId>slf4j-simple</artifactId>
-      <scope>test</scope>
+      <optional>true</optional>
     </dependency>
     <dependency>
       <groupId>com.helger</groupId>
@@ -151,6 +160,7 @@
         <extensions>true</extensions>
         <configuration>
           <instructions>
+            <Main-Class>com.helger.en16931.cii2ubl.cli.CIIToUBLConverter</Main-Class>
             <Automatic-Module-Name>com.helger.en16931-cii2ubl</Automatic-Module-Name>
             <Export-Package>com.helger.en16931-cii2ubl.*</Export-Package>
             <Import-Package>!javax.annotation.*,*</Import-Package>
@@ -171,6 +181,36 @@
           </excludes>
         </configuration>
       </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-shade-plugin</artifactId>
+        <version>3.2.1</version>
+        <configuration>
+          <filters>
+            <filter>
+              <artifact>*:*</artifact>
+              <excludes>
+                <exclude>META-INF/*.SF</exclude>
+                <exclude>META-INF/*.DSA</exclude>
+                <exclude>META-INF/*.RSA</exclude>
+              </excludes>
+            </filter>
+          </filters>
+        </configuration>
+        <executions>
+          <execution>
+            <phase>package</phase>
+            <goals>
+              <goal>shade</goal>
+            </goals>
+            <configuration>
+              <shadedArtifactAttached>true</shadedArtifactAttached>
+              <shadedClassifierName>full</shadedClassifierName> <!-- Any name that makes sense -->
+            </configuration>
+          </execution>
+        </executions>
+
+      </plugin>
     </plugins>
   </build>
 </project>
diff --git a/src/main/java/com/helger/en16931/cii2ubl/cli/CIIToUBLConverter.java b/src/main/java/com/helger/en16931/cii2ubl/cli/CIIToUBLConverter.java
new file mode 100644
index 0000000..58589d2
--- /dev/null
+++ b/src/main/java/com/helger/en16931/cii2ubl/cli/CIIToUBLConverter.java
@@ -0,0 +1,129 @@
+package com.helger.en16931.cii2ubl.cli;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.Serializable;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.Callable;
+import java.util.stream.Collectors;
+
+import com.helger.commons.error.list.ErrorList;
+import com.helger.commons.io.file.FilenameHelper;
+import com.helger.en16931.cii2ubl.CIIToUBL21Converter;
+import com.helger.en16931.cii2ubl.EUBLCreationMode;
+import com.helger.ubl21.UBL21Writer;
+import com.helger.ubl21.UBL21WriterBuilder;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import oasis.names.specification.ubl.schema.xsd.invoice_21.InvoiceType;
+import picocli.CommandLine;
+import picocli.CommandLine.Command;
+import picocli.CommandLine.Option;
+import picocli.CommandLine.Parameters;
+
+/**
+ * Main
+ */
+@Command(description = "CII to UBL Converter.", name = "CIItoUBLConverter", mixinStandardHelpOptions = true, separator = " ")
+public class CIIToUBLConverter implements Callable<Integer> {
+
+    private static final Logger log = LoggerFactory.getLogger(CIIToUBLConverter.class);
+
+    @Option(names = "--ubl", defaultValue = "2.1", description = "Version of the target UBL Format (default: ${DEFAULT-VALUE})")
+    private String UBLVersion;
+
+    @Option(names = "--mode", defaultValue = "INVOICE", description = "Allowedvalues:${COMPLETION-CANDIDATES}")
+    private EUBLCreationMode mode;
+
+    @Option(names = { "-t",
+            "--target" }, paramLabel = "out", defaultValue = ".", description = "The target directory for result output (default: ${DEFAULT-VALUE})")
+    private String outputDir;
+
+    @Parameters(arity = "1..*", description = "One or more Files")
+    private List<File> files;
+
+    // doing the business
+    public Integer call() throws Exception {
+        try {
+            init();
+        } catch (IOException e) {
+            log.error("Could not initialize converter", e.getLocalizedMessage());
+        }
+        // TODO switch between versions
+        final CIIToUBL21Converter converter = new CIIToUBL21Converter();
+        converter.setUBLCreationMode(mode);
+        final ErrorList errorList = new ErrorList();
+
+        Serializable invoice = null;
+        InvoiceType ublInvoiceType = null;
+        File destFile = null;
+        UBL21WriterBuilder<InvoiceType> aWriter = null;
+
+        for (File f : this.files) {
+            log.debug("Converting file={}", f.toString());
+            invoice = converter.convertCIItoUBL(f, errorList);
+            ublInvoiceType = (InvoiceType) invoice;
+            destFile = new File(this.outputDir, FilenameHelper.getBaseName(f) + "-ubl.xml");
+            aWriter = UBL21Writer.invoice().setFormattedOutput(true);
+            aWriter.write(ublInvoiceType, destFile);
+        }
+
+        return 0;
+    }
+
+    private void init() throws IOException {
+        this.outputDir = normalizeOutputDirectory(this.outputDir);
+        this.files = normalizeInputFiles(this.files);
+    }
+
+    private String normalizeOutputDirectory(String dir) {
+
+        log.debug("CLI option output directory={}", dir);
+        String result = "";
+        result = Paths.get(dir).toAbsolutePath().normalize().toString();
+        log.debug("Normalized output directory={}", result);
+        return result;
+    }
+
+    private List<File> normalizeInputFiles(List<File> files) throws IOException {
+        List<File> normalizedFiles = new ArrayList<File>();
+
+        List<File> dirFiles = new ArrayList<File>();
+        for (File file : files) {
+            if (file.isDirectory()) {
+                log.debug("Is a diractory={}", file.toString());
+                // collecting readable and normalized absolute path files
+                dirFiles = Files.walk(file.toPath()).filter(p -> Files.isReadable(p) && !Files.isDirectory(p))
+                        .map(p -> normalizeFile(p)).peek(f -> log.debug("Add file={}", f.toString()))
+                        .collect(Collectors.toList());
+                normalizedFiles.addAll(dirFiles);
+            } else if (file.canRead()) {
+                log.debug("Is a file={}", file.toString());
+                normalizedFiles.add(normalizeFile(file.toPath()));
+            }
+        }
+        return normalizedFiles;
+
+    }
+
+    private static File normalizeFile(Path path) {
+
+        return new File(path.toAbsolutePath().normalize().toString());
+
+    }
+
+    public static void main(final String[] args) {
+
+        log.info("Starting CII to UBL Converter");
+        final CommandLine cmd = new CommandLine(new CIIToUBLConverter());
+        cmd.setCaseInsensitiveEnumValuesAllowed(true);
+        final int exitCode = cmd.execute(args);
+        System.exit(exitCode);
+    }
+}