diff --git a/commander.go b/commander.go
index ae81042..abd3b89 100644
--- a/commander.go
+++ b/commander.go
@@ -1,6 +1,7 @@
 package main
 
 import (
+	"log"
 	"os/exec"
 	"strings"
 )
@@ -11,12 +12,19 @@ type Commander interface {
 }
 
 type DefaultCommander struct {
+	logger *log.Logger
 }
 
 func (c DefaultCommander) Exec(cmd *exec.Cmd) (string, error) {
-	output, err := cmd.CombinedOutput()
+	if c.logger != nil {
+		c.logger.Println(strings.Join(cmd.Args, " "))
+	}
 
+	output, err := cmd.CombinedOutput()
 	if err != nil {
+		if c.logger != nil {
+			c.logger.Println(err)
+		}
 		return "", &ShellError{strings.Join(cmd.Args, " "), err}
 	}
 
@@ -24,8 +32,15 @@ func (c DefaultCommander) Exec(cmd *exec.Cmd) (string, error) {
 }
 
 func (c DefaultCommander) ExecSilently(cmd *exec.Cmd) error {
+	if c.logger != nil {
+		c.logger.Println(strings.Join(cmd.Args, " "))
+	}
+
 	err := cmd.Run()
 	if err != nil {
+		if c.logger != nil {
+			c.logger.Println(err)
+		}
 		return &ShellError{strings.Join(cmd.Args, " "), err}
 	}
 	return nil
diff --git a/main.go b/main.go
index 5c10965..77813e1 100644
--- a/main.go
+++ b/main.go
@@ -3,6 +3,7 @@ package main
 import (
 	"fmt"
 	"io/ioutil"
+	"log"
 	"os"
 	"path/filepath"
 
@@ -33,7 +34,17 @@ func main() {
 		os.Exit(1)
 	}
 
-	commander := DefaultCommander{}
+	var logger *log.Logger
+	if options.Debug {
+		logFile, err := os.Create(filepath.Join(userConfigDir, "smug.log"))
+		if err != nil {
+			fmt.Fprintln(os.Stderr, err.Error())
+			os.Exit(1)
+		}
+		logger = log.New(logFile, "", 0)
+	}
+
+	commander := DefaultCommander{logger}
 	tmux := Tmux{commander}
 	smug := Smug{tmux, commander}
 
diff --git a/options.go b/options.go
index cde6dac..1729874 100644
--- a/options.go
+++ b/options.go
@@ -9,7 +9,7 @@ import (
 const usage = `Smug - tmux session manager.
 
 Usage:
-	smug <command> <project> [-w <window>]... [--attach]
+	smug <command> <project> [-w <window>]... [--attach] [--debug]
 
 Options:
 	-w List of windows to start. If session exists, those windows will be attached to current session.
@@ -27,6 +27,7 @@ type Options struct {
 	Project string
 	Windows []string
 	Attach  bool
+	Debug   bool
 }
 
 func ParseOptions(p docopt.Parser, argv []string) (Options, error) {
@@ -50,6 +51,11 @@ func ParseOptions(p docopt.Parser, argv []string) (Options, error) {
 		return Options{}, err
 	}
 
+	debug, err := arguments.Bool("--debug")
+	if err != nil {
+		return Options{}, err
+	}
+
 	var windows []string
 
 	if strings.Contains(project, ":") {
@@ -60,5 +66,5 @@ func ParseOptions(p docopt.Parser, argv []string) (Options, error) {
 		windows = arguments["-w"].([]string)
 	}
 
-	return Options{cmd, project, windows, attach}, nil
+	return Options{cmd, project, windows, attach, debug}, nil
 }
diff --git a/options_test.go b/options_test.go
index 024768d..1a581d9 100644
--- a/options_test.go
+++ b/options_test.go
@@ -13,19 +13,19 @@ var usageTestTable = []struct {
 }{
 	{
 		[]string{"start", "smug"},
-		Options{"start", "smug", []string{}, false},
+		Options{"start", "smug", []string{}, false, false},
 	},
 	{
 		[]string{"start", "smug", "-wfoo"},
-		Options{"start", "smug", []string{"foo"}, false},
+		Options{"start", "smug", []string{"foo"}, false, false},
 	},
 	{
 		[]string{"start", "smug:foo,bar"},
-		Options{"start", "smug", []string{"foo", "bar"}, false},
+		Options{"start", "smug", []string{"foo", "bar"}, false, false},
 	},
 	{
-		[]string{"start", "smug", "--attach"},
-		Options{"start", "smug", []string{}, true},
+		[]string{"start", "smug", "--attach", "--debug"},
+		Options{"start", "smug", []string{}, true, true},
 	},
 }
 
diff --git a/smug.go b/smug.go
index 43f37b5..4eebb6d 100644
--- a/smug.go
+++ b/smug.go
@@ -114,7 +114,6 @@ func (smug Smug) Start(config Config, windows []string, attach bool) error {
 		}
 	}
 
-	var createdWindows []string
 	for wIndex, w := range config.Windows {
 		if (len(windows) == 0 && w.Manual) || (len(windows) > 0 && !Contains(windows, w.Name)) {
 			continue
@@ -125,17 +124,12 @@ func (smug Smug) Start(config Config, windows []string, attach bool) error {
 			windowRoot = filepath.Join(sessionRoot, w.Root)
 		}
 
-		var window string
-
-		if (wIndex == 0 || len(createdWindows) == 0) && !sessionExists {
-			window = ses + w.Name
-		} else {
-
-			window, err = smug.tmux.NewWindow(ses, w.Name, windowRoot)
+		window := ses + w.Name
+		if (!sessionExists && wIndex > 0 && len(windows) == 0) || (sessionExists && len(windows) > 0) {
+			_, err = smug.tmux.NewWindow(ses, w.Name, windowRoot)
 			if err != nil {
 				return err
 			}
-			createdWindows = append(createdWindows, window)
 		}
 
 		for _, c := range w.Commands {
diff --git a/smug_test.go b/smug_test.go
index 47144ae..839360b 100644
--- a/smug_test.go
+++ b/smug_test.go
@@ -98,6 +98,40 @@ var testTable = []struct {
 			"win2",
 		},
 	},
+	{
+		Config{
+			Session: "ses",
+			Root:    "root",
+			Windows: []Window{
+				{
+					Name:     "win1",
+					Manual:   false,
+					Commands: []string{"command1", "command2"},
+				},
+				{
+					Name:     "win2",
+					Manual:   false,
+					Commands: []string{"command3", "command4"},
+				},
+			},
+		},
+		[]string{
+			"tmux has-session -t ses",
+			"tmux new -Pd -s ses -n win1 -c root",
+			"tmux send-keys -t ses:win1 command1 Enter",
+			"tmux send-keys -t ses:win1 command2 Enter",
+			"tmux select-layout -t ses:win1 even-horizontal",
+			"tmux neww -Pd -t ses: -n win2 -c root",
+			"tmux send-keys -t ses:win2 command3 Enter",
+			"tmux send-keys -t ses:win2 command4 Enter",
+			"tmux select-layout -t ses:win2 even-horizontal",
+			"tmux attach -d -t ses:",
+		},
+		[]string{
+			"tmux kill-session -t ses",
+		},
+		[]string{},
+	},
 }
 
 type MockCommander struct {