How do I open an old file without extensions?

As an example an old MacDraw 1.7 document "md" without extension:

file command displays no details:

file md
md: data

mdls displays file type & creator and Golden Gate Finder > Get Info displays "MacDraw document":

mdls md
kMDItemFSCreatorCode                   = "MDRW"
kMDItemFSTypeCode                      = "DRWG"
kMDItemKind                            = "MacDraw document"

If I remove file type & creator (with GraphicConverter) Golden Gate Finder > Get Info displays "Unix Executable File":

mdls md_edit
kMDItemFSCreatorCode                   = ""
kMDItemFSTypeCode                      = ""
kMDItemKind                            = "Unix Executable File"

I could not find a matching file signature in a few online databases:

xxd -l 4 -g 1 -u md
00000000: 44 52 57 47                                      DRWG

Some files need a longer dump and a 4 byte offset but neither its signature was not found:

xxd -l 8 -g 1 -u -s +4 md 
00000004: 4D 44 00 06 00 03 00 00                          MD......

https://www.garykessler.net/library/file_sigs.html

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

https://www.filesignatures.net

GraphicConverter 12.5.4 can not properly open that MacDraw 1.7 document but it offers to open MacDraw II document with:

The latest LibreOffice 26.8.0.3 opens MacDraw 1.7 document OK:

That sample MacDraw 1.7 document is for a few days at:

https://www.dropbox.com/scl/fi/k7udus4i8ov511mv0owgw/md?rlkey=poktdkjvatnhbzz6u9ya5gk60&dl=0

Click once on one of these files in the Finder and press opt+cmd+i and see if it tells you what file type it is, or if the extension is simply hidden. If the latter, you can unhide the extension and reveal the file extension, if indeed it does exist.

The current LibreOffice Draw (26.8.1) can open either of the ClarisDraw or MacDraw formats, and a ton of other graphic file formats. GraphicConverter can also open MacDraw files.

Select the File, then go to the Finder menu on the top of the screen and choose Get Info. You can post a screenshot of what you see there and it will tell you what kind of file it is.

Are these without extension, or without an associated app? (How to enable Show Extensions in Finder.)

Or open Terminal app, and type the four letters “file” followed by a space, then drag one of the files into the Terminal window to add the file path to the “file” command, and press return. This file (file magic) command will try to ascertain the file contents.)

Matti,

The xxd utility will force a trailing newline on the byte sequence. I punctuate with spaces and trim that newline:

xxd -p -u -l 4 md | sed -E 's/.{2}/& /g;s/[[:space:]]*$//'

44 52 57 47

or slightly more user syntax friendly:

xxd -p -u -l 4 md | fold -w2 | paste -sd' ' - | perl -pe 'chomp if eol'

44 52 57 47

I also have an AppleScript that opens that Wiki List of file signatures and performs a Safari Find of that passed byte string to (occasionally) get a match. Too unreliable to post here.

Bad news first, you might not be able to open them, not without a commensurately old Macintosh™ (today's "Mac" moniker was not "officially" in use back then).

Old, pre-Mac OS X files required no extensions. Extensions were eventually adopted as part of Apple's eventual transition to the Intel platform. Instead, they used four byte "type" and "creator" codes. For readability, those four bytes would be represented in case-sensitive ASCII characters.

For example a text file's type might be "TEXT" and its creator might be "MWWP" for a file created using MacWrite, and "saved as" a text file. A launchable application program (we call them "apps" today) would have a type of "APPL". Get it?

In such a manner it was possible for the Macintosh Finder to determine which program to launch when double-clicking a data file, and for that program to be able to open a variety of different file types.

A developer would register their program's "creator" code with Apple (ref below). Apple would either accept or reject the request. They never publicly divulged a comprehensive list of creators.

Determine those file types will be problematic today. As Mac Jim ID suggested "Get Info" might help though.

https://web.archive.org/web/20020207055638/http://developer.apple.com/dev/cftype/faq.html

Matti,

The xxd utility will force a trailing newline on the byte sequence. I punctuate with spaces and trim that newline:

xxd -p -u -l 4 md | sed -E 's/.{2}/& /g;s/[[:space:]]*$//'

44 52 57 47

or slightly more user syntax friendly:

xxd -p -u -l 4 md | fold -w2 | paste -sd' ' -

44 52 57 47

But there is still the trailing newline to content with.

I also have an AppleScript that opens that Wiki List of file signatures and performs a Safari Find of that passed byte string to (occasionally) get a match. Too unreliable to post here.

"the other way" to open files is to launch the App you think might be able to open it, and see if

File > Open ...

shows that filename black (can be opened) or gray (can't)

The get info did not indicate what the file type is. I like your suggestion to get GraphicConverter to try next.

One type of file when opened in TextEdit begins with ±EXPWVp and the other with ±EXPWs. I have an older LibreOffice which I will update. Thanks for the help.