diff --git a/main.go b/main.go
index c430412..9555d7e 100644
--- a/main.go
+++ b/main.go
@@ -20,7 +20,7 @@ type LineReader interface {
 
 var (
 	inputFile   = flag.String("i", "", "/path/to/input.json (optional; default is stdin)")
-	outputFile  = flag.String("o", "", "/path/to/output.json (optional; default is stdout)")
+	outputFile  = flag.String("o", "", "/path/to/output.csv (optional; default is stdout)")
 	outputDelim = flag.String("d", ",", "delimiter used for output values")
 	verbose     = flag.Bool("v", false, "verbose output (to stderr)")
 	showVersion = flag.Bool("version", false, "print version string")