La respuesta corta es stat y solicita el campo de permisos:
stat -f "%p" file
Es probable que la aplicación, las instrucciones o la memoria estén equivocadas. Desde la página del manual, hay 4 dígitos en la representación octal para los modos en macOS:
Modes may be absolute or symbolic. An absolute mode is an octal number
constructed from the sum of one or more of the following values:
4000 (the set-user-ID-on-execution bit) Executable files with
this bit set will run with effective uid set to the uid of
the file owner. Directories with the set-user-id bit set
will force all files and sub-directories created in them to
be owned by the directory owner and not by the uid of the
creating process, if the underlying file system supports
this feature: see chmod(2) and the suiddir option to
mount(8).
2000 (the set-group-ID-on-execution bit) Executable files with
this bit set will run with effective gid set to the gid of
the file owner.
1000 (the sticky bit) See chmod(2) and sticky(8).
0400 Allow read by owner.
0200 Allow write by owner.
0100 For files, allow execution by owner. For directories,
allow the owner to search in the directory.
0040 Allow read by group members.
0020 Allow write by group members.
0010 For files, allow execution by group members. For directo-
ries, allow group members to search in the directory.
0004 Allow read by others.
0002 Allow write by others.
0001 For files, allow execution by others. For directories
allow others to search in the directory.
For example, the absolute mode that permits read, write and execute by
the owner, read and execute by group members, read and execute by others,
and no set-uid or set-gid behaviour is 755 (400+200+100+040+010+004+001).
Hice un archivo convenientemente llamado 040775 y apliqué permisos; puede ver que el 040 borra todos los elementos adheridos (ya que es la parte 0775 lo que importa), setUID, setGID bits, por lo que obtiene 0775 si intenta configurar 040775.
mac:foo me$ touch 040775
mac:foo me$ stat -f "%p" 040775
100644
mac:foo me$ chmod 040775 040775
mac:foo me$ stat -f "%p" 040775
100775
mac:foo me$ chmod 4775 040775
mac:foo me$ ls -l
-rwsrwxr-x 1 me wheel 0 May 10 20:30 040775
mac:foo me$ chmod 040775 040775
mac:foo me$ ls -l
-rwxrwxr-x 1 me wheel 0 May 10 20:30 040775
He editado un poco lo anterior y no hice todos los stat
y ls
, pero debería ayudarte a buscar en los archivos existentes y probar si mi experiencia de que solo los últimos 4 dígitos se interpretan como una máscara de bit octal para establecer los permisos como se documenta en la página man de chmod.