diff --git a/command.go b/command.go
index 1867d22c9..5cf889dd7 100644
--- a/command.go
+++ b/command.go
@@ -627,7 +627,7 @@ func argsMinusFirstX(args []string, x string) []string {
 }
 
 func isFlagArg(arg string) bool {
-	return ((len(arg) >= 3 && arg[1] == '-') ||
+	return ((len(arg) >= 3 && arg[0:2] == "--") ||
 		(len(arg) >= 2 && arg[0] == '-' && arg[1] != '-'))
 }