enhance ilm show, add ilm update, rename modify to update everywhere (#58)

cmd/ilm.go

@@ -36,7 +36,8 @@ func Ilm(conf *cfg.Config) *cli.Command {
 			IlmStatus(conf),
 			IlmList(conf),
 			IlmShow(conf),
-			IlmCreate(conf),
+			IlmCreate(conf, false),
+			IlmCreate(conf, true),
 			IlmForecast(conf),
 			IlmExplain(conf),
 		},
@@ -127,12 +128,22 @@ func IlmShow(conf *cfg.Config) *cli.Command {
 	}
 }
 
-func IlmCreate(conf *cfg.Config) *cli.Command {
+func IlmCreate(conf *cfg.Config, modify bool) *cli.Command {
+	name := "create"
+	alias := "+"
+	usage := "create a new lifecycle policy"
+
+	if modify {
+		name = "update"
+		usage = "update an lifecycle policy"
+		alias = "upd"
+	}
+
 	return &cli.Command{
-		Name:      "create",
-		Aliases:   []string{"+"},
-		Usage:     "create a index lifecycle policy",
-		UsageText: "create [options] <policy>",
+		Name:      name,
+		Aliases:   []string{alias},
+		Usage:     usage,
+		UsageText: name + " [options] <policy>",
 
 		Flags: []cli.Flag{
 			&cli.StringFlag{