I would like to understand how to use the permission system in CentOS to achieve the following: The system has the following users:user1user2user3And the following directory structure.. /dir1  /dir2  /dir3User 2 executes files within dir 2, so it needs to be able to write to themUser 3 executes files within dir 3, so it needs to be able to write to themUser 2 should not be able to modify dir3User 3 should not be able to modify dir2The problem comes when i need User 1 to be able to modify dir2 and dir3.. 
Common user to modify files owned by 'other' users
linux;centos;permissions;files