iOS (iPhone, iPad, iPodTouch) view real-time console log terminal

The solution documented by Apple in Technical Q&A QA1747 Debugging Deployed iOS Apps for Xcode 6 is:

1. Choose Window -> Devices from the Xcode menu.
2. Choose the device in the left column.
3. Click the up-triangle at the bottom left of the right hand panel to show the device console.

Two options:

libimobiledevice is installable via homebrew and works great. Its idevicesyslog tool works similarly to deviceconsole (below), and it supports wirelessly viewing your device's syslog (!)

I've written more about that on Tumblr tl;dr:

brew install libimobiledevice
idevice_id --list // list available device UDIDs
idevicesyslog -u <device udid>

with the device connected via USB or available on the local wireless network.

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(Keeping for the historical record, from 2013:) deviceconsole from rpetrich is a much less wacked-out solution than ideviceconsole above. My fork of it builds and runs in Xcode 5 out of the box, and the Build action will install the binary to /usr/local/bin for ease of use.

As an additional helpful bit of info, I use it in the following style which makes it easy to find the device I want in my shell history and removes unnecessary > lines that deviceconsole prints out.

deviceconsole -d -u <device UDID> | uniq -u && echo "<device name>"

EDIT: Please use @cbowns solution - deviceconsole is compatible with iOS9 and much easier to use.

This is a open-source program that displays the iDevice's system log in Terminal (in a manner similar to tail -F). No jailbreak is required, and the output is fully grep'able so you can filter to see output from your program only. What's particularly good about this solution is you can view the log whether or not the app was launched in debug mode from XCode.

Here's how:

Grab the libimobiledevice binary for Mac OS X from my github account at https://github.com/benvium/libimobiledevice-macosx/zipball/master

Follow the install instructions here: https://github.com/benvium/libimobiledevice-macosx/blob/master/README.md

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

Taken from my blog at http://pervasivecode.blogspot.co.uk/2012/06/view-log-output-of-any-app-on-iphone-or.html

Just open the Application Console.app on mac osX.

You can find it under Applications > Utilities > Console.

On the left side of the application all your connected devices are listed.