var
  F:Textfile;
  filename:String;
  SvrName:String;
  inifile:Tinifile;
begin
   inifile:=Tinifile.Create('c:\load\Ctais.ini');
   filename:=inifile.ReadString('datasource','path','C:\oracle\ora81\network\ADMIN\tnsnames.ora') ;
   SvrName:=inifile.ReadString('Server0','SvrName','');
   AssignFile(F,filename); 
   Append(F);   
   try
   Writeln(F,svrName);
   finally
   Closefile(F);    
end;
end;
这段代码只能在文件tnsnames.ora的末尾添加文本,如果我想在特定的行添加文本,并覆盖该行以有的文本,该如何作?