Use common data folders for two users instead of separate ones

Question

I have a 15.04 machine with basically 2 user accounts, an admin and a restricted user. What I want is that both of them have separate home directories (for system/application settings etc.), but use the same data directories:

• Desktop
• Documents
• Music
• Pictures
• Public
• Templates
• Videos
• and maybe some more, program-specific data folders...

Those directories therefore have to be outside of those two users' home directory, e.g. be located in /home/shared-data/ or something like that and both users need full access on them.

If I navigate through that directory and back upwards in the hierarchy, I want to come out in the same user's home directory where I started, if possible. And the real shared directory should not be publicly accessible by new users, just by those users I specifically allowed.

Also, new files and folders created there should automatically be accessible to both users.

So what is the easiest way to move all data from the users' current home directories to this external location, then replacing the original folders with links/mounts/whatever to the new shared directory, so that it looks like before?

Answer 1

Don't move anything. Just use links. For example, say your normal user is usera and your second one is userb. Presumably, userb is a brand new account and doesn't have any data you want to keep. So, delete the directories in question and recreate them as links, then set up the right permissions:

1. Delete the directories and recreate as links

   sudo rmdir ~userb/{Desktop,Documents,Music,Pictures,Public,Templates,Videos}
   for i in Desktop Documents Music Pictures Public Templates Videos; do
       sudo -u userb ln -s ~usera/"$i" ~userb
   done
   

2. Create a new group and add both users to this group:

   sudo groupadd foo
   sudo usermod -aG foo usera
   sudo usermod -aG foo userb
   

3. Change the group ownership of the directories you want to share to this new group:

   chgrp -R foo ~usera/{Desktop,Documents,Music,Pictures,Public,Templates,Videos}
   

4. Set the permissions on the target directories to rwx for the group and set the SETGID bit on the directory so that new files will belong to the right group.

   chmod -R g+rwxs ~usera/{Desktop,Documents,Music,Pictures,Public,Templates,Videos}
   

5. Set the Access Control List settings to set the permissions for newly created files/directories:

   setfacl -d -m g:foo:rwx ~usera/{Desktop,Documents,Music,Pictures,Public,Templates,Videos}
   

That's it. Now, the directories in ~/userb are links to those in ~/usera and both users have read/write access to them.