IOS: copy a file in documents folder

Copies txtFile from resource to document if not already present.

NSFileManager *fileManager = [NSFileManager defaultManager];
NSError *error;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];

NSString *txtPath = [documentsDirectory stringByAppendingPathComponent:@"txtFile.txt"];

if ([fileManager fileExistsAtPath:txtPath] == NO) {
    NSString *resourcePath = [[NSBundle mainBundle] pathForResource:@"txtFile" ofType:@"txt"];
    [fileManager copyItemAtPath:resourcePath toPath:txtPath error:&error];
}

If you want to overwrite every time then try this:

if ([fileManager fileExistsAtPath:txtPath] == YES) {
    [fileManager removeItemAtPath:txtPath error:&error];
}

NSString *resourcePath = [[NSBundle mainBundle] pathForResource:@"txtFile" ofType:@"txt"];
[fileManager copyItemAtPath:resourcePath toPath:txtPath error:&error];