diff --git a/cmd/adif.go b/cmd/adif.go
index 517cd6b..6fe1a46 100644
--- a/cmd/adif.go
+++ b/cmd/adif.go
@@ -17,11 +17,9 @@ limitations under the License.
 */
 
 import (
-
 	"fmt"
 	"github.com/spf13/cobra"
-//	"log"
-
+	//	"log"
 	//"strings"
 )
 
@@ -34,7 +32,7 @@ var adifCmd = &cobra.Command{
 
 	Run: func(cmd *cobra.Command, args []string) {
 		fmt.Println("adif called")
-		fmt.Println("Inputfile: ",inputFilename)
+		fmt.Println("Inputfile: ", inputFilename)
 		loadFile()
 	},
 }
diff --git a/cmd/adif_filename.go b/cmd/adif_filename.go
new file mode 100644
index 0000000..49eb06b
--- /dev/null
+++ b/cmd/adif_filename.go
@@ -0,0 +1,70 @@
+package cmd
+
+/*
+Copyright © 2020 Jean-Marc Meessen, ON4KJM <on4kjm@gmail.com>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import (
+	"os"
+	//"log"
+	"fmt"
+)
+
+// does the target file exist?
+// is the file defined
+//	remove the extention
+
+//returning "" is considered as invalid
+func buildOutputFilename(output string, input string, overwrite bool) (outputFilename string, wasOK bool) {
+	outputFilename = ""
+
+	//validate that input is populated (should never happen if properly called)
+	if input == "" {
+		return "", false
+	}
+
+	//an output was provided by the user
+	if output != "" {
+		info, err := os.Stat(output)
+		if os.IsNotExist(err) {
+			return output, true
+		}
+		//It exisits but is a directory
+		if info.IsDir() {
+			fmt.Println("Error: specified output exists and is a directory")
+			return "", false
+		}
+		if overwrite {
+			//user accepted to overwrite the file
+			return output, true
+		}
+		return "", false
+	}
+
+	//if output is not null, check if file exits
+	//if it exists, check the flag
+	//if output
+	return outputFilename, true
+}
+
+// fileExists checks if a file exists and is not a directory before we
+// try using it to prevent further errors.
+func fileExists(filename string) bool {
+	info, err := os.Stat(filename)
+	if os.IsNotExist(err) {
+		return false
+	}
+	return !info.IsDir()
+}
diff --git a/cmd/adif_filename_test.go b/cmd/adif_filename_test.go
new file mode 100644
index 0000000..582f269
--- /dev/null
+++ b/cmd/adif_filename_test.go
@@ -0,0 +1,76 @@
+package cmd
+
+import (
+	"os"
+	"testing"
+)
+
+const testDir string = "test_dir"
+const testFile string = "test.adi"
+
+func setupTestCase(t *testing.T) func(t *testing.T) {
+	t.Log("setup test case")
+	//create test directory
+	os.Mkdir(testDir, os.FileMode(0522))
+	//create test file
+	f, _ := os.OpenFile(testFile, os.O_WRONLY|os.O_CREATE, 0666)
+	defer f.Close()
+
+	return func(t *testing.T) {
+		t.Log("teardown test case")
+		//delete test directory
+		os.Remove(testDir)
+		//detete test file
+		os.Remove(testFile)
+	}
+}
+
+func Test_buildOutputFilename(t *testing.T) {
+	type args struct {
+		output    string
+		input     string
+		overwrite bool
+	}
+	tests := []struct {
+		name               string
+		args               args
+		wantOutputFilename string
+		wantWasOK          bool
+	}{
+		{
+			"input file not provided",
+			args{input: "", output: "xxx", overwrite: false},
+			"", false,
+		},
+		{
+			"Output file does not exist",
+			args{input: "a file", output: "output.adi", overwrite: false},
+			"output.adi", true,
+		},
+		{
+			"Output name is a directory",
+			args{input: "a file", output: testDir, overwrite: false},
+			"", false,
+		},
+		{
+			"Output exisit but no overwrite",
+			args{input: "a file", output: testFile, overwrite: false},
+			"", false,
+		},
+	}
+
+	teardownTestCase := setupTestCase(t)
+	defer teardownTestCase(t)
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			gotOutputFilename, gotWasOK := buildOutputFilename(tt.args.output, tt.args.input, tt.args.overwrite)
+			if gotOutputFilename != tt.wantOutputFilename {
+				t.Errorf("buildOutputFilename() gotOutputFilename = %v, want %v", gotOutputFilename, tt.wantOutputFilename)
+			}
+			if gotWasOK != tt.wantWasOK {
+				t.Errorf("buildOutputFilename() gotWasOK = %v, want %v", gotWasOK, tt.wantWasOK)
+			}
+		})
+	}
+}
diff --git a/cmd/adif_write.go b/cmd/adif_write.go
new file mode 100644
index 0000000..68fcd39
--- /dev/null
+++ b/cmd/adif_write.go
@@ -0,0 +1,21 @@
+package cmd
+
+/*
+Copyright © 2020 Jean-Marc Meessen, ON4KJM <on4kjm@gmail.com>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// does the target file exist?
+// is the file defined
+//	remove the extention
diff --git a/cmd/load.go b/cmd/load.go
index b472575..5ba2200 100644
--- a/cmd/load.go
+++ b/cmd/load.go
@@ -72,9 +72,9 @@ func loadFile() {
 		txtlines = append(txtlines, scanner.Text())
 	}
 
-    if error := scanner.Err(); error != nil {
-        log.Fatal(error)
-    }
+	if error := scanner.Err(); error != nil {
+		log.Fatal(error)
+	}
 
 	file.Close()