Thursday 28 June 2012

Take an iPhone or iPad Screenshot from the Command-line


Here's another tip using the great libimobiledevice library http://www.libimobiledevice.org/, originally built to manage iOS devices on Linux.

Taking app screenshots is a bit of a pain. We tend to do the following:

  • Run the app
  • Press Home+Power together to take a photo,
  • Go to the photo library
  • Find the photos
  • Email them to ourselves.

Using this method you can type a Terminal command, and have the screen appear directly on your computer. Much easier.
Here's how:

Connect your device, open up Terminal.app and type:

idevicescreenshot

It'll save a .TIFF file to the current directory. Easy!

Tuesday 26 June 2012

View the log output of any app on iPhone or iPad


Here's another tip using the great libimobiledevice library http://www.libimobiledevice.org/, originally built to manage iOS devices on Linux.

This method shows you how you can view the log output (e.g. what you see in Xcode when running in debug mode) on any app, whether it's an AppStore build or an AdHoc build.

Some apps are more talkative than others - it all depends on how careful the developers were to remove log messages in release builds.

I find this most useful for debugging issues in release versions of our apps. If a user reports a sequence of actions causes a crash, you can try this out while watching the log from your app.

Here's how:


Connect your device, open up Terminal.app and type:

idevicesyslog

Up pops a real-time display of the device's system log.

With it being a console app, you can filter the log using unix commands, such as grep


For instance, see all log messages from a particular app:

idevicesyslog | grep myappname



Install iPhone / iPad / iOS App IPA without iTunes or Xcode

Using the great libimobiledevice library http://www.libimobiledevice.org/, originally built to manage iOS devices on Linux, it's possible to do a bunch of cool things, including installing an app directly on a connected device without needing to use iTunes or Xcode.

Here's how:

Now connect your iDevice, open Terminal.app and type:

ideviceinstaller -i myApp.ipa

Note: Your IPA will need to have a valid code signature and mobileprovision file for the install to succed. This system is NOT a way around iOSs security!