diff --git a/hash_cache.go b/hash_cache.go
index 55c8212..e0f7277 100644
--- a/hash_cache.go
+++ b/hash_cache.go
@@ -29,7 +29,7 @@ func InitCache() {
 	}
 
 	go func() {
-		ticker := time.NewTicker(10 * time.Second)
+		ticker := time.NewTicker(FlagUpdateHashFileInterval)
 		defer ticker.Stop()
 		for range ticker.C {
 			if err := WriteCache(); err != nil {
diff --git a/main.go b/main.go
index 6b728b2..b248f67 100644
--- a/main.go
+++ b/main.go
@@ -17,9 +17,10 @@ import (
 )
 
 var ( // flags
-	FlagSourceDir = envvars.String("SOURCE_PATH", "/video")
-	FlagTargetDir = envvars.String("TARGET_PATH", "/audio")
-	FlagCacheFile = envvars.String("CACHE_FILE", "/hashes.bin")
+	FlagSourceDir              = envvars.String("SOURCE_PATH", "/video")
+	FlagTargetDir              = envvars.String("TARGET_PATH", "/audio")
+	FlagCacheFile              = envvars.String("CACHE_FILE", "/hashes.bin")
+	FlagUpdateHashFileInterval = envvars.Duration("UPDATE_CACHE_FILE_INTERVAL", 10*time.Second)
 )
 
 func main() {