procedure TForm1.Button1Click(Sender: TObject);
var F:TextFile;
fName:string;
begin
fName:='error.txt';
AssignFile(F,fName);
if FileExists(fName) then Append(F) else Rewrite(F);
Writeln(F,'this is string');
CloseFile(F);
end;
var F:TextFile;
fName:string;
begin
fName:='error.txt';
AssignFile(F,fName);
if FileExists(fName) then Append(F) else Rewrite(F);
Writeln(F,'this is string');
CloseFile(F);
end;