Sharing Directories on LinuxΒΆ

Add a Group:

$ sudo addgroup webadmin

Add an existing user to a group:

$ sudo usermod -a -G webadmin myusername

Change an existing users primary group:

$ sudo usermod -g webadmin myusername

View the a user’s identity and primary group information:

$ id myusername

Create the shared folder:

$ mkdir myshareddir

Change the group owner for the group:

$ chown -R myusername:webadmin myshareddir

Give write permissions to the group:

$ chmod -R 775  myshareddir

Set an inherited group on files created within a directory, you can use the sgid bit on the directory permissions:

$ chmod -R 2775 myshareddir

or...

$ chmod -R g+s myshareddir

To make the default file permissions rw for group as well as user, you can change the umask to 0002 (either for all users in /etc/profile, or for individual users in /etc/.bashrc). Just append umask 0002 to either of those files.