Untitled file without extention on my desktop

If you have not deleted the Untitled file, you may still be able to identify what it is by the first four bytes of the file.

I have written an AppleScript that obtains the first four hexadecimal bytes of a selected file and displays that in a dialog. Although you can search in the list of file signatures for that four-byte sequence, and identify the extension, not every file is represented on that web page.

Copy and paste the following AppleScript into the Script Editor. To open the Script Edtor, just tape the Spotlight symbol on the Finder menu bar 🔍 and enter script and a return. Create a new script on your Desktop and with the pasted AppleScript, click the hammer icon and then the run button.

Code:

use scripting additions

-- https://en.wikipedia.org/wiki/List_of_file_signatures

set theUnk to POSIX path of (choose file with prompt "Select unknown file")
-- split the four contiguous hex codes into groups of two with spaces
set hexcode to (do shell script "xxd -l 4 -p " & theUnk & " | sed 's/../& /g' | tr 'a-z' 'A-Z'")
display dialog "File signature is:  " & hexcode with title "File Signature"
return

Some common signatures:

• Any file that is a .zip container even if the extension is different (e.g. docx, pages, etc.)
  • 50 4b 03 04
• Any .dmg container
  • 45 52 02 00
  • 42 5a 68 39
  • 78 da 63 60
  • Possibly others
• Compiled Swift, C++, or dylib library executable
  • CF FA ED FE
• PDF
  • 25 50 44 46
• JPG, JPEG
  • FF D8 FF E0
• PNG, animated PNG
  • 89 50 4E 47
• TIFF, including multi-page TIFF
  • 4D 4D 00 2A
• GIF, including animated GIF
  • 47 49 46 38
• ICNS, Apple icon
  • 69 63 6E 73
• SVG, vector
  • 3C 3F 78 6D
• PS, Postscript
  • 25 21 50 53
• PSD, Photoshop
  • 38 42 50 53
• RAW Camera images
  • CR2, CR3 (same as TIFF), and iPhone DNG
    • 4D 4D 00 2A
  • ARW, Sony
    • 49 49 2A 00
  • RW2, Panasonic
    • 49 49 55 00
  • DNG, Leica
    • 49 49 2A 00

When you click File > Get Info, what is the file kind?

Is there no suffix displayed for the file in the info panel?

Since it's on your desktop - not a typical location for important system or app files - I think you'd be okay simply deleting it. If you don't want to do that, then tuck it into a junk folder somewhere and forget about it.

Delete the file, though " I've run it through VirusTotal too "

Total Virus Software  is not needed and actually may have compromised the Security of the Operating System

What is malware? - Apple Community

Windows-like viruses that self-replicate and affect macOS don’t exist because of the underlying UNIX Foundation and permission limitations.

The macOS operating system resides in a sealed and read-only volume that can’t be opened by users or third-party applications.

Mac app security enhancements are sufficient to protect computers from malware.

Errata:

One can simplify the do shell script in the previous post. Change to the following:

set hexcode to (do shell script "xxd -u -l 4 -p " & theUnk & " | sed 's/../& /g'")