Ubuntu is a variety of Debian Linux. I installed it on my new laptop. Sometimes there are some things that don’t work immediately. K3b, the CD and DVD burning software had some problems.
Owners, groups and chmod
Linux is a serious OS and maybe some of the features are a bit too much on a laptop. One of the things I struggled with is how to get all the permissions right that K3b is allowed to write a CD, and only K3b at that moment.
There are several things that play a role. The user has certain rights and can be member of a group. In my case ‘paul’ is a user, but also ‘root’ and also ‘burning’ and ‘cdrom’ are users and groups. The user with absolute rights is ‘root’, and in the documentation of K3b it is advised to use the ‘root’-user to burn CD’s and DVD’s.
To start a program that is in the Kmenu list as root:
- Right-click on the menu-icon to get in the editors-mode of the menu
- Go to the program you want to start up as root
- Click on ‘Run as a defferent user’ without filling in the Username
- That’s it!
Well, not completely. The CDROM-group owns the right to read of the CD/DVD and the K3b program wants to have the unique rights to access the CD/DVD. (That is at least what I understand of it, spelling the error-log of K3b).
Sometimes the group-settings have to be changed. To do that:
- Start up a terminal program
- Type ‘sudo chgrp root /dev/sg0’ (the sg0 can be sg1 or something like that. Check the error-log of the K3b-program.
This works with me. I don’t understand every detail of the whole process. Sometimes the group changes after a reboot. Then I just have to chgrp the CD/DVD-player once more.
How to run a program from the menu in ‘sudo’-mode
Just click on the ‘Run as a different user’ in the menu-editor. That is the nice thing I discovered.
