Show usage if no field spec is given

rs · Mar 12, 2018 · 575aa9c · 575aa9c
1 parent e407187
commit 575aa9c
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/main.go b/main.go
@@ -34,6 +34,12 @@ func main() {
  }
  interval := flag.Duration("interval", time.Second, "Sampling interval")
  flag.Parse()
+
+ if len(flag.Args()) == 0 {
+ flag.Usage()
+ os.Exit(1)
+ }
+
  fields, err := aggr.NewFields(flag.Args())
  if err != nil {
  fatal("invalid argument: ", err)