How to redirect the nslog output to file instead of console

Step 1: Include following function in AppDelegate:

 - (void) redirectConsoleLogToDocumentFolder {       NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,                                                     NSUserDomainMask, YES);       NSString *documentsDirectory = [paths objectAtIndex:0];       NSString *logPath = [documentsDirectory stringByAppendingPathComponent:@"console.log"];       freopen([logPath fileSystemRepresentation],"a+",stderr); }

Step 2: Call this function at the start of function applicationDidFinishLaunchingWithOptions...

Thats it, Every NSLog() will now get redirected to this console.log file, which you can find in the documents directory.

Recently i have faced similar requirement and this is how i have done it.

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{    // Override point for customization after application launch.    [self redirectConsoleLogToDocumentFolder];    return YES;}- (void) redirectConsoleLogToDocumentFolder{    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,                                                         NSUserDomainMask, YES);    NSString *documentsDirectory = [paths objectAtIndex:0];    NSString *logPath = [documentsDirectory stringByAppendingPathComponent:@"console.txt"];    freopen([logPath fileSystemRepresentation],"a+",stderr);} 

And Now if you want to this console to user

-(void)displayLog{    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);    NSString *documentsDirectory = [paths firstObject];    NSString *logPath = [documentsDirectory stringByAppendingPathComponent:@"console.txt"];    NSError *err = nil;    NSString *fileContents = [NSString stringWithContentsOfFile:logPath                                                       encoding:NSUTF8StringEncoding                                                          error:&err];    if (fileContents == nil) {        NSLog(@"Error reading %@: %@", logPath, err);    } else {        self.textView.text = fileContents;    }}

You may be interested in CocoaLumberjack. It is a very flexible logging framework for both Mac OS X and iOS. One logging statement can be sent not only to the console but to a file simultaneously. Plus it is actually faster then NSLog. I use it in a project that has common code for both OS X and iOS.