gistfile1.txt

NSRange searchStringRange = [textView rangeOfString:@"string to search goes here" options:NSCaseInsensitiveSearch];
    if (searchStringRange.location != NSNotFound) {
        // Got the search string.
        NSString *searchStringInTextView = [textView substringWithRange:searchStringRange];
        NSLog(@"The search string is: %@", searchStringInTextView);
    }