Create folder if doesn't exist

gistfile1.m

// Documents directory
NSString *documentsPath = [NSSearchPathForDirectoriesInDomains(
                                                               NSDocumentDirectory, 
                                                               NSUserDomainMask, YES) 
                           objectAtIndex:0];

NSString *dataPath = [documentsPath stringByAppendingPathComponent:@"folderName"];

// Create folder if does not exist.
if (![[NSFileManager defaultManager] fileExistsAtPath:dataPath]) {
    [[NSFileManager defaultManager] createDirectoryAtPath:dataPath 
                              withIntermediateDirectories:NO 
                                               attributes:nil 
                                                    error:&error]; 
}