private void subs(RichTextBox obj, int start, int end) {
StringBuilder sbdnsmasqlast = new StringBuilder();
foreach(string s in rtbList.Lines) {
if(s.Length > 0) {
sbdnsmasqlast.AppendLine(end == 0 ? s.Substring(start) : s.Substring(start, s.Length - start - end));
}
}
rtbList.Text = sbdnsmasqlast.ToString();
}