diff --git a/bitmask/main.go b/bitmask/main.go
index 29263accb3357137853ec4339ade44540754e352..bdb47c0f7ead20dd26e6214a396e8fb264c25c54 100644
--- a/bitmask/main.go
+++ b/bitmask/main.go
@@ -20,7 +20,6 @@ import (
 	"errors"
 	"fmt"
 	"log"
-	"os"
 	"time"
 
 	"github.com/pebbe/zmq4"