Author: Jonas Bilinkevicius

How can I read a file and get the first 10 bytes of that file in its hexadecimal 
format?

Answer:

1   function FirstTenBytes(const sFile: TFileName): string;
2   var
3     oIn: TFileStream;
4     iRead: Integer;
5     iMaxRead: Integer;
6     iData: Byte;
7   begin
8     Result := '';
9     oIn := TFileStream.Create(sFile, fmOpenRead or fmShareDenyNone);
10    try
11      iMaxRead := 10;
12      if iMaxRead > oIn.Size then
13        iMaxRead := oIn.Size;
14      for iRead := 1 to iMaxRead do
15      begin
16        oIn.read(iData, 1);
17        Result := Result + IntToHex(iData, 2);
18      end;
19    finally
20      FreeAndNil(oIn);
21    end;
22  end;