Update readme

README.md

@@ -19,4 +19,45 @@ xtool is a cross-platform (Linux/WSL/macOS) tool that replicates Xcode functiona
 1. Follow the guide to install `xtool`
     - [Linux](#)
     - macOS: TBD
-2. Create and run your first xtool-powered app by following the [tutorial](#)!
+2. Create and run your first xtool-powered app by following the [tutorial](#)
+
+## Use xtool via the command line
+
+```bash
+$ xtool --help
+OVERVIEW: Cross-platform Xcode replacement
+
+USAGE: xtool <subcommand>
+
+OPTIONS:
+  -h, --help              Show help information.
+
+CONFIGURATION SUBCOMMANDS:
+  setup                   Set up xtool for iOS development
+  auth                    Manage Apple Developer Services authentication
+  sdk                     Manage the Darwin Swift SDK
+
+DEVELOPMENT SUBCOMMANDS:
+  new                     Create a new xtool SwiftPM project
+  dev                     Build and run an xtool SwiftPM project
+  ds                      Interact with Apple Developer Services
+
+DEVICE SUBCOMMANDS:
+  devices                 List devices
+  install                 Install an ipa file to your device
+  uninstall               Uninstall an installed app
+  launch                  Launch an installed app
+
+  See 'xtool help <subcommand>' for detailed help.
+```
+
+## …or as a library!
+
+xtool includes a library that you can use to interact with Apple Developer Services, iOS devices, and more from your own app. You can use this by adding `XKit` as a SwiftPM dependency.
+
+```swift
+// package dependency:
+.package(url: "https://github.com/xtool-org/xtool", .upToNextMinor(from: "1.2.0"))
+// target dependency:
+.product(name: "XKit", package: "xtool")
+```