How to get the output of an OS X application on the console, or to a file?

I am writing a Cocoa application with Mono embedded. I want to run and see my debug output in Terminal. On the Cocoa side I am using NSLog(), and on the Mono side I am using Debug.Write(). I can see my debug output in Xcode's console, but not in Terminal. This is what I tried:

$: open /path/build/Debug/MyProgram.app
$: open /path/build/Debug/MyProgram.app > output
$: open /path/build/Debug/MyProgram.app 2> output

in a terminal but I do not my output on the console or in 'ouput'.

What's the correct command?

PS. My ultimate goal is to write a vim plugin to manage, build, run, debug the xcode project. You can save me this hassle if you can get this vi input manager to work with xcode.

Chris gave a good overview of how the Console works, but to specifically answer your question: If you want to see the results directly in your Terminal, you need to run the built product as a child of the Terminal, which means using something like

/path/debug/build/MyProgram.app/Contents/MacOS/MyProgram

to launch the app.

Terminal on Mac OS X is just another application. Opening a terminal window for text I/O is not an inherent capability of every application as it is on Windows.

Furthermore, open /path/to/MyApp.app does not execute MyApp.app as a subprocess of your shell, it sends a message to the operating system's launch infrastructure asking it to execute the application in a normal fashion, the same as if it were double-clicked in the Finder or clicked in the Dock. That's why you're not able to just redirect its output to see what your app is sending to stdout or stderr.

You can use Console.app to see the output of applications launched in the normal manner, because the launch infrastructure specifically sends their stdout and stderr there. You can also use the asl routines to query the log, or perform more sophisticated logging if you so desire.

Open Console.app in /Applications/Utilities. All NSLog output will be printed in the System log.

Or, if you run it from within Xcode, all of the output will be printed in the Debug console.

I'm not on my Mac right now and don't recall the command sequence or the menu the Debug Console is in, possibly the Build menu?

Overview

The idea is to simply run the app from command line using ios-deploy.

Instructions

1. Install ios-deploy
2. Run the app from xcode (make sure it runs successfully)
3. go to xcode menu > preferences > locations and click on arrow in derived data:
4. in the derived data directory, search for your .app file under Build/intermediates/Products
5. in the terminal type the following

ios-deploy --debug --bundle

then drag the .app file from step 4 unto the terminal.. you should have something like this

ios-deploy --debug --bundle path/to/your/applicationName.app

and that's it! The app should successfully run and all the logs will go to your terminal.