How can I find out what kind of file this is?

Question

I have this file, and I have absolutely no idea what kind of file it is.

When I open it in Notepad++ it reads as

ð    X      döS   

or

How can I figure out what this is, and how to modfiy it?

Answer 1

Whenever you have some unidentified file, the best way I know to analyze it (at least using a computer-scientific method) is the program TrID from Marco Pontello.
According to its definition:

TrID is an utility designed to identify file types from their binary signatures.

Example:

C:\TrID>trid c:\test\doc\lasik_info.doc
 TrID/32 - File Identifier v2.10 - (C) 2003-11 By M.Pontello          
 Collecting data from file: c:\test\doc\lasik_info.doc
 Definitions found: 4150
 Analyzing...
  70.7% (.DOC) Microsoft Word document (58000/1/5)
  29.3% (.) Generic OLE2 / Multistream Compound File (24000/1)

Latest version (27/02/14) includes 5.276 file types.
A real must-have program if you use to need file type identification.
Saddly, I must admit that, with this your file, has no results:

c:\Temp\trid.exe download
TrID/32 - File Identifier v2.02 - (C) 2003-06 By M.Pontello
Definitions found:  5276
Analyzing...
Collecting data from file: C:\Temp\download
       Unknown!

Additional points:

• Versions for both Windows and Linux.

Answer 2

It's a binary data. I don't touch windows so I'm unsure what utilities you can use to edit it, but you need a hex editor.

claw:~ jonv$ file download
download: data
claw:~ jonv$ strings download
claw:~ jonv$ hexdump download
0000000 0d f0 13 00 01 00 00 00 58 09 00 00 00 00 64 f6
0000010 02 53 7f 01 00 00 00
0000017