diff --git a/cmd/disk.go b/cmd/disk.go
index 5f21c79..c72f2d0 100644
--- a/cmd/disk.go
+++ b/cmd/disk.go
@@ -2,6 +2,7 @@ package cmd
 
 import (
   "fmt"
+  "io"
   "log"
   "os"
   "os/exec"
@@ -30,7 +31,14 @@ var diskCmd = &cobra.Command{
     outfile := fmt.Sprintf("of=%s", tempfile)
 
     ddCmd := exec.Command("dd", "bs=1M", blocksCount, "if=/dev/zero", outfile)
-    ddCmd.Stderr = os.Stdout
+
+    if Log != "false" {
+      f, _ := os.Create(Log)
+      ddCmd.Stderr = io.MultiWriter(os.Stderr, f)
+    } else {
+      ddCmd.Stderr = os.Stdout
+    }
+
     err = ddCmd.Run()
     if err != nil {
       log.Fatalf("cmd.Run() failed with %s\n", err)
diff --git a/cmd/net.go b/cmd/net.go
index 5d365dd..140ea4d 100644
--- a/cmd/net.go
+++ b/cmd/net.go
@@ -5,6 +5,8 @@ import (
 
   "github.com/showwin/speedtest-go/speedtest"
   "github.com/spf13/cobra"
+
+  "git.metaunix.net/bitgoblin/hardware-tests/lib"
 )
 
 var netCmd = &cobra.Command{
@@ -22,7 +24,14 @@ var netCmd = &cobra.Command{
   		s.DownloadTest(false)
   		s.UploadTest(false)
 
-  		fmt.Printf("Latency: %s, Download: %f, Upload: %f\n", s.Latency, s.DLSpeed, s.ULSpeed)
+      // put together the result
+  		result := fmt.Sprintf("Latency: %s, Download: %f, Upload: %f\n", s.Latency, s.DLSpeed, s.ULSpeed)
+      // log the result if it's configured, otherwise print it out
+      if Log != "false" {
+        lib.WriteToFile(Log, result)
+      } else {
+        fmt.Printf("%s", result)
+      }
   	}
   },
 }
diff --git a/cmd/ping.go b/cmd/ping.go
index 1c15a1d..66ad20f 100644
--- a/cmd/ping.go
+++ b/cmd/ping.go
@@ -31,7 +31,8 @@ var pingCmd = &cobra.Command{
     	result += fmt.Sprintf("round-trip min/avg/max/stddev = %v/%v/%v/%v\n",
     		stats.MinRtt, stats.AvgRtt, stats.MaxRtt, stats.StdDevRtt)
 
-      if Log != nil {
+      // log the result if it's configured, otherwise print it out
+      if Log != "false" {
         lib.WriteToFile(Log, result)
       } else {
         fmt.Printf("%s", result)