merge branch 'pr-1129'

LGTMs: @mrunalp @cyphar
Closes #1129

Author: cyphar

create.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"fmt"
 	"os"
 
 	"github.com/urfave/cli"
@@ -48,6 +49,11 @@ command(s) that get executed on start, edit the args parameter of the spec. See
 		},
 	},
 	Action: func(context *cli.Context) error {
+		if context.NArg() != 1 {
+			fmt.Printf("Incorrect Usage.\n\n")
+			cli.ShowCommandHelp(context, "create")
+			return fmt.Errorf("runc: \"create\" requires exactly one argument")
+		}
 		spec, err := setupSpec(context)
 		if err != nil {
 			return err