Linux – group member cannot delete file with rw permission – Super User https://superuser.com/questions/784952/linux-group-member-cannot-delete-file-with-rw-permission
linux – Why can’t I delete a file where I have group write permissions on? – Super User http://superuser.com/questions/373115/why-cant-i-delete-a-file-where-i-have-group-write-permissions-on
filesystems – How does the sticky bit work? – Unix & Linux Stack Exchange http://unix.stackexchange.com/questions/79395/how-does-the-sticky-bit-work