diff --git a/cmd/cli/config.go b/cmd/cli/config.go
index 9b8d9f8..1189989 100644
--- a/cmd/cli/config.go
+++ b/cmd/cli/config.go
@@ -3,7 +3,7 @@ package cli
 type Config struct {
 	Files FileList
 	Query struct {
-		Period     string
+		Period     Period
 		Sort       string
 		NoRounding bool
 		Depth      int
diff --git a/cmd/cli/flag.go b/cmd/cli/flag.go
index 9fa1d0e..213fd77 100644
--- a/cmd/cli/flag.go
+++ b/cmd/cli/flag.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 	"strings"
+	"time"
 )
 
 type FlagStringArray []string
@@ -33,3 +34,35 @@ func (fileList *FileList) Set(s string) error {
 	}
 	return (*FlagStringArray)(fileList).Set(s)
 }
+
+type Period struct {
+	Start time.Time
+	Stop  time.Time
+}
+
+func (period Period) Empty() bool {
+	return period.Stop.Sub(period.Start) == 0
+}
+
+func (period *Period) String() string {
+	return fmt.Sprintf("%s..%s", period.Start, period.Stop)
+}
+
+func (period *Period) Set(s string) error {
+	if result, err := time.Parse("2006", s); err == nil {
+		period.Start = result
+		period.Stop = result.AddDate(1, 0, 0).Add(-1 * time.Minute)
+		return nil
+	}
+	if result, err := time.Parse("2006-01", s); err == nil {
+		period.Start = result
+		period.Stop = result.AddDate(0, 1, 0).Add(-1 * time.Minute)
+		return nil
+	}
+	if result, err := time.Parse("2006-01-02", s); err == nil {
+		period.Start = result
+		period.Stop = result.AddDate(0, 0, 1).Add(-1 * time.Minute)
+		return nil
+	}
+	return fmt.Errorf("unimplemented format: %s", s)
+}
diff --git a/cmd/cli/main.go b/cmd/cli/main.go
index 8d0048a..9d14420 100644
--- a/cmd/cli/main.go
+++ b/cmd/cli/main.go
@@ -3,6 +3,7 @@ package cli
 import (
 	"flag"
 	"fmt"
+	"log"
 	"os"
 	"slices"
 
@@ -14,7 +15,7 @@ func Main() {
 
 	fs := flag.NewFlagSet(os.Args[0], flag.ContinueOnError)
 	fs.Var(&config.Files, "f", "paths to files")
-	fs.StringVar(&config.Query.Period, "period", "", "period")
+	fs.Var(&config.Query.Period, "period", "period")
 	fs.StringVar(&config.Query.Sort, "S", "", "sort ie date")
 	fs.BoolVar(&config.Query.NoRounding, "no-rounding", false, "no rounding")
 	fs.IntVar(&config.Query.Depth, "depth", 0, "depth grouping")
@@ -47,8 +48,14 @@ func Main() {
 		panic(err)
 	}
 
-	if period := config.Query.Period; period != "" {
-		panic(period)
+	if period := config.Query.Period; !period.Empty() {
+		after := period.Start.Format("2006-01-02")
+		before := period.Stop.Format("2006-01-02")
+		deltas = deltas.Like(
+			ledger.LikeAfter(after),
+			ledger.LikeBefore(before),
+		)
+		log.Printf("period=%+v after=%s before=%s", period, after, before)
 	}
 
 	if depth := config.Query.Depth; depth > 0 {