can i update my local text file on iphone

i have a text file so can i update this text开发者_如何学运维 file from web ??? lets say i have

   1. NSString *filePath = [[NSBundle mainBundle] pathForResource:@"MyFile" ofType:@"txt"];  
   2. NSData *myData = [NSData dataWithContentsOfFile:filePath];  
   3. if (myData) {  
   4.     // do something useful  
   5. } 

right now Myfile.text is having 10 data so how to insert 10 more to this data??

plz help

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Files stored inside your app bundle will not be writable.

You will have to make a copy of the file and store it in the Documents or Library folder before you will be able to edit it.