如何重定向nslog输出到文件而不是控制台

我有在OS X上运行的可可应用程序。我使用NSLog进行调试。现在我想将日志语句重定向到文件而不是控制台。

I have cocoa application running on OS X. I have used NSLog for debugging purpose. Now I want to redirect the log statements to file instead of console.

我使用这种方法，但它导致控制台和文件中的日志。

I have used this method but it results logging in Console as well as in file.

- (BOOL)redirectNSLog
{
    // Create log file
    [@"" writeToFile:@"/NSLog.txt" atomically:YES encoding:NSUTF8StringEncoding error:nil];
    id fileHandle = [NSFileHandle fileHandleForWritingAtPath:@"/NSLog.txt"];
    if (!fileHandle)    return NSLog(@"Opening log failed"), NO;
    [fileHandle retain];

    // Redirect stderr
    int err = dup2([fileHandle fileDescriptor], STDERR_FILENO);
    if (!err)   return  NSLog(@"Couldn't redirect stderr"), NO;

    return  YES;
}

有可能在控制台中没有日志语句，

Is it possible to not have log statement in console but only in file ??