How can I setup a group writeable directory?

Question

$ whoami
meder
$ cd /var/www
$ sudo mkdir html
$ sudo groupadd web
$ sudo usermod -a -G web meder
$ sudo usermod -a -G web medertest
$ sudo chown meder:web html
$ sudo chmod -R g+rwx html

The problem is, anytime I create a new file in /var/www/html even though the group is set to web, it is only writeable by the original user.

I was given the advice of setting the umask to be 002 because the default is what causes the problems. But I would have to do this for all users in that group, and as far as I know it would be tedious having all of them modify ~/.bashrc to have umask 002. Even if I can do it myself with a shell command for all of those users, it still seems too tedious.

Can anyone offer any advice on having a group writeable directory?

Answer 1

First, enable the SGID bit on your directory:

sudo chmod g+s html

This will make new files created inside that directory inherit the parent's group ownership.

There is no inheritance of permission levels in the POSIX permission model. However, this can be done with Access Control Lists, without having to worry about umask settings:

sudo setfacl -d -m group:web:rwx html

It's a real bummer that umask cannot be assigned on a per-directory basis.

Answer 2

You need to set the setgid bit on the directory.

chmod g+s html