If you want an user to be able to access a file or a folder, you need to set the correct permissions for it.
First of all, you need to create a specific group for the three users.
Do it like so :
groupadd mygroup where
mygroup is the name of the group, for instance
Then, you need to add your users to the group :
useradd -G mygroup user where
mygroup is the group you've just created above. Replace
user with the user you want to add to the group. In your case, run the command three times with Edwin, Mike and Brian.
Then, make sure the file's owner is one of the user in the group you've creating. Use
chown the change the ownership of a file or folder (assuming that your file is called myFile). So you would do
chown Edwin myFile.
The permissions are set up with the command
In your case, you would do
chmod g+rw myFile. This changes the permissions for the group the file owner is in (
+ adds permissions and
rw stands for read and write. If you want the users to be able to execute the file, use
To change a file permission for just one user, use
chmod u+rwx myFile. This will add all the permissions to the user owning the file.
(Note : Never copy commands from website, type them yourself)