To write (append) text to a file

    NSString *oldContents = [TextFileManager readStringFromFile:@"data.txt"];
    NSString *newString = self.textInput.text;
    NSString *contents;
    if ([oldContents isEqual:@""])
        contents = [NSString stringWithFormat:@"%@",newString];
    else
        contents = [NSString stringWithFormat:@"%@\n%@",oldContents,newString];
    [TextFileManager writeStringToFile:contents:@"data.txt"];

To read from a text file

    NSString *contents =
    [TextFileManager readStringFromFile:@"data.txt"];
    // parse contents
    NSArray *lines = [contents componentsSeparatedByString:@"\n"];
    for( int i = 0; i < lines.count; i++)
    {
        NSString *line = lines[i];
        NSLog(@"%d: %@", i, line);
    }

To read from a web page

    String *urlString = self.url.text;
    NSString *contents = [TextFileManager readStringFromURL:urlString];
    // parse contents
    NSArray *lines = [contents componentsSeparatedByString:@"\n"];
    for( int i = 0; i < lines.count; i++)
    {
        NSString *line = lines[i];
        NSLog(@"%d: %@", i, line);
    }