Additions:
$ ls -ld myshareddir
drwxrwsr-x 2 www-data www-data 4096 2007-09-20 09:42 myshareddir
Deletions:
$ ls
drwxrwsr-x 2 www-data www-data 4096 2007-09-20 09:42 mywebsite
chmod
change permissions
ugo +=- rwx
you can change permissions for the (u)ser, (g)roup, (o)others or (a)ll
ugo +=- ugo
propagate user permissions to group
propagate user permissions to all
ugo +=- st
the group sticky bit on a directory allows a group or team to share files on a server
make sure the directory group sticky bit is set on any shared directories
(so that any new files you create are owned by the group)
verify
verify your directory sticky bit
$ ls
drwxrwsr-x 2 www-data www-data 4096 2007-09-20 09:42 mywebsite
umask
make sure your UMASK is set to 0002 in ~/.bashrc (or in /etc/bashrc /etc/profile or /etc/login.defs so that any new files you create are group writable)
verify
view your umask
REFERRERS
SystemSecurity