How can I get the console logs from the iOS Simulator?

iOS Simulator > Menu Bar > Debug > Open System Log

Old ways:

iOS Simulator prints its logs directly to stdout, so you can see the logs mixed up with system logs.

Open the Terminal and type: tail -f /var/log/system.log

Then run the simulator.

EDIT:

This stopped working on Mavericks/Xcode 5. Now you can access the simulator logs in its own folder: ~/Library/Logs/iOS Simulator/<sim-version>/system.log

You can either use the Console.app to see this, or just do a tail (iOS 7.0.3 64 bits for example):

tail -f ~/Library/Logs/iOS\ Simulator/7.0.3-64/system.log

EDIT 2:

They are now located in ~/Library/Logs/CoreSimulator/<simulator-hash>/system.log

tail -f ~/Library/Logs/CoreSimulator/<simulator-hash>/system.log

You can view the console for the iOS Simulator via desktop Safari. It's similar to the way you use desktop Safari to view the console for physical iOS devices.

Whenever the simulator is running and there's a webpage open, there'll be an option under the Develop menu in desktop safari that lets you see the iOS simulator console:

Develop -> iPhone Simulator -> site name

There's an option in the Simulator to open the console

Debug > Open System Log

or use the

keyboard shortcut: ⌘/

iOS 8 and iOS 9

Under iOS 8 and iOS 9 this location is now:

~/Library/Logs/CoreSimulator/<DEVICE_CODE>

So, the following will work:

tail -f ~/Library/Logs/CoreSimulator/<DEVICE_CODE>/system.log

The DEVICE_CODE value can be found via the following console command:

instruments -s devices

You should not rely on instruments -s. The officially supported tool for working with Simulators from the command line is xcrun simctl.

The log directory for a device can be found with xcrun simctl getenv booted SIMULATOR_LOG_ROOT. This will always be correct even if the location changes.

Now that things are moving to os_log it is easier to open Console.app on the host Mac. Booted simulators should show up as a log source on the left, just like physical devices. You can also run log commands in the booted simulator:

# os_log equivalent of tail -f
xcrun simctl spawn booted log stream --level=debug

# filter log output
xcrun simctl spawn booted log stream --predicate 'processImagePath endswith "myapp"'
xcrun simctl spawn booted log stream --predicate 'eventMessage contains "error" and messageType == info'

# a log dump that Console.app can open
xcrun simctl spawn booted log collect

# open location where log collect will write the dump
cd `xcrun simctl getenv booted SIMULATOR_SHARED_RESOURCES_DIRECTORY`

If you want to use Safari Developer tools (including the JS console) with a webpage in the Simulator: Start one of the simulators, open Safari, then go to Safari on your mac and you should see Simulator in the menu.

You can open a URL in the Simulator by dragging it from the Safari address bar and dropping on the Simulator window. You can also use xcrun simctl openurl booted <url>.