diff --git a/go.mod b/go.mod
index 4bcb5e4..a273d99 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,8 @@
 module kumoly.io/tools/kclock
 
 go 1.17
+
+require (
+	github.com/mattn/go-isatty v0.0.14 // indirect
+	golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c // indirect
+)
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..cb37ebd
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,4 @@
+github.com/mattn/go-isatty v0.0.14 h1:yVuAays6BHfxijgZPzw+3Zlu5yQgKGP2/hcQbHb7S9Y=
+github.com/mattn/go-isatty v0.0.14/go.mod h1:7GGIvUiUoEMVVmxf/4nioHXj79iQHKdU27kJ6hsGG94=
+golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c h1:F1jZWGFhYfh0Ci55sIpILtKKK8p3i2/krTr0H1rg74I=
+golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
diff --git a/main.go b/main.go
index b32668c..ec64c58 100644
--- a/main.go
+++ b/main.go
@@ -7,18 +7,23 @@ import (
 	"os/signal"
 	"syscall"
 	"time"
+
+	"github.com/mattn/go-isatty"
 )
 
 var (
 	Version = "0.0.0"
 	Build   = "alpha"
+
+	local    string
+	flagTick string
+	flagVer  bool
 )
 
 func main() {
-	var local string
-	var flagVer bool
 
 	flag.StringVar(&local, "local", fmt.Sprint(time.Local), "set local manually")
+	flag.StringVar(&flagTick, "tick", "1s", "ticking interval")
 	flag.BoolVar(&flagVer, "v", false, "show version")
 	flag.Usage = func() {
 		fmt.Fprintf(os.Stderr, "Usage: kclock [options]\n")
@@ -43,20 +48,37 @@ func main() {
 }
 
 func watch() {
+	interval, err := time.ParseDuration(flagTick)
+	if err != nil {
+		panic(err)
+	}
+	color := isatty.IsTerminal(os.Stdout.Fd())
+	if !color {
+		color = isatty.IsCygwinTerminal(os.Stdout.Fd())
+	}
 	quit := make(chan os.Signal, 1)
 	signal.Notify(quit, os.Interrupt, syscall.SIGINT, syscall.SIGTERM)
 
 	start := time.Now()
-	next := time.Now().Truncate(time.Second).Add(time.Second)
-	<-time.After(time.Until(next))
-	tick := time.Tick(time.Second)
-	fmt.Printf("\n")
+	<-time.After(time.Until(time.Now().Truncate(time.Second).Add(time.Second)))
+	tick := time.Tick(interval)
+	if color {
+		fmt.Printf("\n")
+	}
 	for {
-		fmt.Printf("\r\033[1A\033[0K\033[92m%v\033[0m\n", time.Now().Truncate(time.Second))
+		if color {
+			fmt.Printf("\r\033[1A\033[0K\033[32m%v\033[0m\n", time.Now().Truncate(time.Second))
+		} else {
+			fmt.Printf("%v\n", time.Now().Truncate(time.Second))
+		}
 		select {
 		case <-tick:
 		case <-quit:
-			fmt.Printf("\r\033[0Ktime elapsed: \033[94m%v\033[0m\n", time.Since(start))
+			if color {
+				fmt.Printf("\r\033[0Ktime elapsed: \033[34m%v\033[0m\n", time.Since(start))
+			} else {
+				fmt.Printf("time elapsed: %v\n", time.Since(start))
+			}
 			return
 		}