diff --git a/main.go b/main.go
new file mode 100644
index 0000000..fe19c37
--- /dev/null
+++ b/main.go
@@ -0,0 +1,35 @@
+package main
+
+import (
+	"fmt"
+	"net"
+	"os"
+
+	"github.com/apparentlymart/go-cidr/cidr"
+)
+
+const usage = "sn <cidr>"
+
+func main() {
+	if len(os.Args) < 2 {
+		fmt.Fprintf(os.Stderr, "usage: %v\n", usage)
+		os.Exit(1)
+	}
+
+	nets := []*net.IPNet{}
+	for _, sn := range os.Args[1:] {
+		_, net, err := net.ParseCIDR(sn)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "%v invalid: %v\n", sn, err)
+			os.Exit(1)
+		}
+		nets = append(nets, net)
+		a, b := cidr.AddressRange(net)
+		l := cidr.AddressCount(net)
+		fmt.Printf("%-16s %-16s %10d\n", a, b, l)
+	}
+	if err := cidr.NoOverlap(nets); err != nil {
+		fmt.Fprintf(os.Stderr, "overlaping networks: %v\n", err)
+		os.Exit(1)
+	}
+}