diff --git a/cmd/main.go b/cmd/main.go
index 225550c..d62cd9c 100644
--- a/cmd/main.go
+++ b/cmd/main.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"strings"
 	"time"
 
 	"github.com/araddon/dateparse"
@@ -35,11 +36,16 @@ func Main(cmd *cobra.Command, args []string) error {
 	//times
 	times := make([]time.Time, 0, len(args)+1)
 	if len(args) == 0 {
-		times = append(times, time.Now())
+		t := time.Now()
+		t = t.Add(viper.GetDuration("add"))
+		t = t.Add(-viper.GetDuration("sub"))
+		times = append(times, t)
 	}
 	for _, arg := range args {
-		t, err := dateparse.ParseStrict(arg)
+		t, err := dateparse.ParseStrict(strings.TrimSpace(arg))
 		exitForErr(err)
+		t = t.Add(viper.GetDuration("add"))
+		t = t.Add(-viper.GetDuration("sub"))
 		times = append(times, t)
 	}
 
@@ -81,8 +87,8 @@ func Main(cmd *cobra.Command, args []string) error {
 		// StampMilli = "Jan _2 15:04:05.000"
 		// StampMicro = "Jan _2 15:04:05.000000"
 		// StampNano  = "Jan _2 15:04:05.000000000"
-		dest := fmt.Sprint(time.Now().UnixNano() / 1000000)
 		if len(viper.GetString("format")) > 0 {
+			dest := ""
 			switch viper.GetString("format") {
 			case "ANSIC":
 				dest = time.ANSIC
@@ -119,8 +125,10 @@ func Main(cmd *cobra.Command, args []string) error {
 				exitForErr(err)
 				dest = d
 			}
+			fmt.Fprintln(stdout, tm.Format(dest))
+			continue
 		}
-		fmt.Fprintln(stdout, tm.Format(dest))
+		fmt.Fprintln(stdout, tm.UnixNano()/1000000)
 	}
 	return nil
 }
diff --git a/cmd/root.go b/cmd/root.go
index 1123c19..f238073 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+	"time"
 
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
@@ -16,11 +17,15 @@ func RootCmd() *cobra.Command {
 		Use:   "ts",
 		Short: "timestamp convert & compare tool",
 		Example: `
-	(timestamp)	$: ts 
-	(format)	$: ts -f "2019/06/25 23:30:10"
-	(before)	$: ts -b "2019/06/25 23:30:10" ; echo $?
-	(after)		$: ts -a "2019/06/25 23:30:10" ; echo $?
-	(timezone)	$: ts -f "2019/06/25 23:30:10" -z "Asia/Shanghai"	
+	(now timestamp)	$: ts
+	(now add)		$: ts --add 1d
+	(now sub)		$: ts --sub 1d
+	(convert)		$: ts "2019/06/24 23:30:10"
+	(pipe)			$: echo "2019/06/24 23:30:10" | ts		
+	(format)		$: ts -f "2019/06/25 23:30:10"
+	(before)		$: ts -b "2019/06/25 23:30:10" ; echo $?
+	(after)			$: ts -a "2019/06/25 23:30:10" ; echo $?
+	(timezone)		$: ts -f "2019/06/25 23:30:10" -z "Asia/Shanghai"	
 	`,
 		Run: func(cmd *cobra.Command, args []string) {
 			//pipe stdin
@@ -37,10 +42,13 @@ func RootCmd() *cobra.Command {
 			exitForErr(Main(cmd, args))
 		},
 	}
+
 	cmd.Flags().StringP("after", "a", "", "after compare")
 	cmd.Flags().StringP("before", "b", "", "before compare")
 	cmd.Flags().StringP("format", "f", "", "time format")
 	cmd.Flags().StringP("timezone", "z", "", "time zone")
+	cmd.Flags().DurationP("add", "", 0*time.Second, "add duration")
+	cmd.Flags().DurationP("sub", "", 0*time.Second, "sub duration")
 	return cmd
 }