issue: you want to share a folder (e.g. your music folder) between a certain number of users. these users need to have read and write permissions on all files in the folder.
solution:
1. create a new group (e.g. "shared")
2. all all users who should be able to access the shared folder to this group
3. make the shared folder rwx for owner and group members: chmod -R 770 folder
4. change the group to shared: chgrp -R shared folder
5. set a umask to ensure all files and folders are created as with a certain rwx value. e.g. umask 002 will create all files as rwxrwx---. the problem is where to set umask globally. i tried:
/etc/profile
/etc/login.defs
~.bash_profile
but none of them change the umask when creating a folder via nautilus or the gnome terminal.
6. set the gid bit to make sure all folders underneath a specified folder have the same group as the parent foldet: chmod -R g+s folder