Add instructions for command line installation on pkg gen

cmd/fleetctl/package.go

@@ -377,13 +377,25 @@ func packageCommand() *cli.Command {
 			}
 
 			path, _ = filepath.Abs(path)
+			var installInstructions = "double-click the installer"
+			switch c.String("type") {
+			case "pkg":
+				installInstructions += fmt.Sprintf(" or run the command `installer -pkg \"%s\" -target /`", path)
+			case "deb":
+				installInstructions += fmt.Sprintf(" or run the command `sudo apt install \"%s\"`", path)
+			case "rpm":
+				installInstructions += fmt.Sprintf(" or run the command `sudo dnf install \"%s\"`", path)
+			case "msi":
+				installInstructions += fmt.Sprintf(" or run the command `msiexec /i \"%s\"` as administrator", path)
+			}
+
 			fmt.Printf(`
 Success! You generated fleetd at %s
 
-To add this device to Fleet, double-click to install fleetd.
+To add this device to Fleet, %s.
 
 To add other devices to Fleet, distribute fleetd using Chef, Ansible, Jamf, or Puppet. Learn how: https://fleetdm.com/learn-more-about/enrolling-hosts
-`, path)
+`, path, installInstructions)
 			if !disableOpenFolder {
 				open.Start(filepath.Dir(path)) //nolint:errcheck
 			}