It is not entirely a problem with Finder. It happens system-wise.
Whenever I create a file in osx, the permission is always set to owner read/write and the rest read only
-rw-r--r-- 1 me mygroup 0 9 Aug 23:18 test
How can I set to 'owner and group read/write'?
Repeating my answer from https://superuser.com/a/1859642/175529, which may be a duplicate of this:
I have not checked which versions of macOS this applies to, but my mac setup script does this:
sudo launchctl config user umask 077
(unfortunately I did not record where I got that from)
To make everything world writable, instead of 077 it would be 000
You can find representations for different sets of permissions at https://wintelguy.com/umask-calc.pl ; in some contexts the numerical representation may require a leading zero
(obligatory warning that making everything world writable is usually a bad idea)
There is a post at Apple Discussion forums about using either /etc/launchd.conf or /etc/launchd-user.conf to set the system-wide umask.
Two files were created:
/etc/launchd.conf(for system-wide global umask) or/etc/launchd-user.conf(for user-specific global umask). The contents of each were simply the single umask command,umask 002or (umask u=rwx,g=rwx,o=rx, I can't remember which variant I used - they're functionally the same, though).
There's also a mention of TinkerTool System, which would help do this in a GUI. However, the discussion ends with the caveat that this may work in the Terminal but not in Finder. I have not tested this myself.
