iOS: How to Use Command Line Arguments

Article written by Brantley C.

To run an app with specific command line arguments, there are two ways to do so:

By default a UE4 iOS app gets its command line arguments from a file called ue4commandline.txt, which is packaged in the IPA file. You can either create it manually and place in your Project/Build/IOS folder before packaging, or if you specify launch options inside the Project Launcher launch profile, it will generate this file for you. You can open up your packaged app’s IPA file (it’s a zip file) and you should be able to see the file that’s there by default.

Alternatively. you can directly specify a command line from Xcode from the Edit Scheme dialog under Run.

Each installed iOS app has its own “Documents” folder which can be read and written to from outside the app. If you turn on the options “Support iTunes File Sharing” and “Support File App” under Project Settings → iOS, you will be able to see the contents of your app’s Documents folder inside the iOS Files app on the iPhone.

You can place a ue4commandline.txt file into the Documents folder (eg by copying it from Dropbox in the Files app) and this will be used the next time you launch the app.