You can change the umask on your system, that's the brute force option, and it will set the default creation mode of all files and folders. You could also set a sticky bit. e.g. chmod 2770 will make the folder you target r/w/x by the owner and group, no permissions for others, and it will ensure any new child folders or files have the same permissions.
tl;dr google umask or sticky bits
You can also add a "sticky group" permission to a folder using the plus modifier
chmod g+s /path/to/dir
Or for everything under the directory
chmod -R g+s /path/to/dir
Amazing. Thank you. I'm a little afraid of making sweeping changes so having two options to research is great.
This is exactly what I was looking for. I just didn't know the vernacular. Thank you.
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