Question

I have two Macs, and a shared folder on a third Windows computer. If I do something like this:

1. Copy an executable console application (not a .app file – a single file which is executable) from Mac 1 to Windows machine
2. Zip executable on Windows machine
3. Copy new zip file to Mac 2 and unzip

The file that comes out of the zip file is still executable. How is the “executable-ness” nature of that file preserved, given that windows permissions system is totally different and doesn’t really have the concept of executable files?

Answer 1

OSX Apps are folders, not files. When copying folders to a file system, that doesn’t have executable bit representation, OSX creates hidden files for the missing attributes. Zipping the App is zipping a folder, including its hidden subfolders. On copy back, OSX will recreate the missing properties from the hidden files.

These hidden folders are called ._.OriginalName

EDIT

After quite extensive discussion in the comments sections, here is a bit of info about simple executable files (execute permission set) as opposed to *.app folders (native OSX applications)

• Ofcourse OSX honours the executable permissions, (set and unset)
• Copying a file to a file system, that does not have a concept of an executable permission (most prominently FAT formated USB sticks), then copying it back after a rename on another OS leaves OSX with the dilemma of whether to see the file as executable or not – the ._.OriginalName metadata store is decoupled from the file by the rename
• OSX solves this dilemma by setting the permissions to 700 or 777, thus making every file executable