Using umask to set group permissions

Question

A long time ago an old friend showed me a way to use an octal or hex umask with a group I think using /etc/profile. I'm not sure.

I'm trying to create group on Debian so that every member of that group when creating a file will produce a file with default permissions 665. And when creating a directory it will have default permissions 775. What are some ways to do this for a group setting?

Thanks

Answer 1

Not really umask aka (user mask) is set by user. You can add to /etc/profile script that will check for the users of that group and will change their Umask accordingly but as far as I know there is no gmask setting to be applied.

Answer 2

There is no group mask for the dir and files as said by karslon. Instead, you can use the group-id

SGID or setgid: It inherits rights of the group of the owner of the file on execution. For directories it also may mean that when a new file is created in the directory it will inherit the group of the directory (and not of the user who created the file).

Numerical Representation of setgid:

Octal Binary   Representation
0   000     setuid, setgid, sticky bits are cleared
1   001     sticky bit is set
2   010     setgid bit is set
3   011     setgid and sticky bits are set
4   100     setuid bit is set
5   101     setuid and sticky bits are set
6   110     setuid and setgid bits are set
7   111     setuid, setgid, sticky bits are set