Customizing Ubuntu for XO

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Revision as of 19:03, 4 April 2008 by 130.164.67.220 (talk)
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Once you've installed Ubuntu, you may quickly discover that it's not completely ready for you to use. Below are some short How-To's on topics I've seen asked a few times. These instructions are probably posted elsewhere, but I wanted to collect them all in one place.

Root password

This is probably the biggest problem users have once the finish installing Ubuntu. XO's root user account has no password and so it's simple to switch to root user using su. Ubuntu doesn't want users to log in as root. They see it as unsafe since as root, you have the power to do anything, including destroy your system. By using su, you gain root power until you decide to give it up. They're worried that you might forget that you're root and accidentally do something bad. So, they disabled directly logging into the root account.

Instead, they provide the sudo command. It runs programs as root without having you actually log in as root. To use it, just put sudo at the very front of your command. For example, if you wanted to install Firefox using apt-get, you would want to type: 

apt-get install firefox

but that would fail since you don't have permission. To get permission using sudo, you need to type: 

sudo apt-get install firefox

It'll then prompt you for your password (not root's) and run the command with root privilege. Once the command (apt-get in this case) finishes, it'll return, leaving you as olpc, not root.

Now, there is a way to use sudo and su to gain root privilege the way you're used to from Sugar, but I'll leave that as a small exercise for you to figure out ;).

Mouse problems

Tap-click

We finally have a fix for this problem, thanks to raduga: http://olpcnews.com/forum/index.php?topic=1585.msg16543#msg16543

Here's what raduga suggested (with some corrections from n2d2 and James_Bucher):

As root, open the /etc/modprobe.d/olpc.conf.dist file and add options mousedev tap_time=0 to the end: 

sudo nano /etc/modprobe.d/olpc.conf.dist

Once the file's open, put this at the bottom: 

options mousedev tap_time=0

The instructions to save and close are at the bottom of the screen. The carat (^) means Control. So, to output (save) a file, it's ^O, which means hold down Control and press O (that's o, as in output).

b. Sensitivity

In the same thread (The trackpad is killing me! Help! (Ubuntu+xfce)), we found that by messing with the settings for the mouse sensitivity, we could almost get the trackpad sensitivity to a useable level. However, we also discovered that as the firmware number increases, the more sensitive it becomes, so not upgrading past version q2d07 is probably best for now. The settings I use are 1/4 sensitivity and 0 threshold. To set them, open a terminal and type: 

xset m 1/4 0

If you want this to execute automatically when Xfce starts, add it to your .xfce4_startup file (/home/olpc/.xfce4_startup). If you don't have the .xfce4_startup file (it should be there if you used the compressed files installation method), see the Creating the Xfce Startup File instructions above.

Changing username and password

Password

Open a terminal and type: 

passwd

It will then prompt you for your current password. If you used the Compressed Files installation method, the password should be olpcolpc. It will then want you to enter your new password twice (to make sure you typed it correctly).

Username

Changing your username isn't as simple as your password, but, it's not very hard either. Before I begin, here are a couple of conventions: new_username = your new username, whenever you see this, replace it with your new username olpc = this is your current username, if your username isn't olpc, replace it with whatever it is

To start, open up a terminal and type: 

sudo usermod -d /home/new_username -i new_username -m olpc

That'll change everything but your password and your group name. Your password can be changed following the instructions above, your group name will take one more step. If you don't want to change your group name, skip the next paragraph.

What are groups? Well, it's part of the file permissions that Linux has. I'll let Wikipedia explain the rest: http://en.wikipedia.org/wiki/Group_identifier_%28Unix%29 . Why bother changing your group name? Well, there's no real need to, but it'd make more sense for your files to belong to the new_username group than to the olpc group. Plus, it's not hard to do. Just type: 

sudo groupmod -n new_username olpc

If sudo is installed (if you used the Compressed Files method, it is), we need to change the sudo information, so in a terminal type: 

EDITOR=/usr/bin/nano sudo visudo

Scroll down to the bottom of the file and change all the olpc in the first column with new_username. If you changed your group name, be sure to also change the line 

new_username      ALL=(root)        NOPASSWD: /bin/chgrp olpc /sys/class/backlight/dcon-bl/brightness

to 

new_username      ALL=(root)        NOPASSWD: /bin/chgrp new_username /sys/class/backlight/dcon-bl/brightness

If you changed your group name, open the .xfce4_startup file in your home directory (/home/new_username/.xfce4_startup) and change the line: 

sudo chgrp olpc /sys/class/backlight/dcon-bl/brightness

to 

sudo chgrp new_username /sys/class/backlight/dcon-bl/brightness

Note: Throughout the rest of these guides, I'll assume that the username is still olpc.

Running graphical programs as root

I don't know why we're running into this problem, but for some reason the .Xauthority file goes missing, which prevents gksu from running, which ends up with us not being able to run graphical programs requiring root privilege. Luckily, there's a simple fix! Just add, to the bottom of your .xfce4_startup file in your home directory (/home/username/.xfce4_startup): 

xauth generate $DISPLAY . trusted

That'll fix the problem once you log out of X, but what about your current X session? Well, you could just log out and start Xfce4 again, but there's another way! Just type in a terminal: 

xauth generate $DISPLAY . trusted

DMM NOTE: I don't think the above the right way to fix this. I think this problem is really because the .Xauthority file sometimes gets set to having root as the owner incorrectly when installing certain packages. See this link for a description of what I think the problem is and the way to fix it: [1]

Installing new software

There are plenty of ways to do this in Ubuntu, but if you're new to Ubuntu, then I'd recommend the Synaptic Package Manager. it's available from the menu, under the System submenu. It'll hopefully ask you for your password. If it says you don't have permission to run it, see the How-To above. If synaptic isn't installed, you can install it using another installation method: apt-get. The apt-get program is a command-line program. Here's an example of how to use it, that happens to install synaptic. Open a terminal and type: 

sudo apt-get install synaptic

6. Rotating the screen

Thanks to cyli's post in the Xfce? thread, it's now possible to rotate the screen in Ubuntu.

First, you need to install the new driver. Visit this website https://launchpad.net/%7Eq-funk/+archive and search for "xserver-xorg-video-amd" in the search bar towards the bottom. It should come back with one result. Show all the files related to that result (click the triangle next to the source name) and download the xserver-xorg-video-amd_2.7.7.6-1ubuntu2_i386.deb file. Open a terminal, change into the directory you downloaded the file to, and run 

sudo dpkg -i xserver-xorg-video-amd_2.7.7.6-1ubuntu2_i386.deb

Finally, download freelikegnu's new xorg.conf file to /etc/X11: 

cd /etc/X11
wget http://www.freelikegnu.org/wp-content/uploads/2008/01/xorg.conf

You can rotate the screen by using 

xrandr -o 2

to flip the screen and 

xrandr -o 0

to return it to normal. info_anarchy and Frihet both wrote scripts that make use of the rotate button:

the keycode for the rotate button can be found with "xbindkeys -k" but it only works for the right gamepad the left arrows and the rotate button dont register... so um.. yeah ..

References

See Also

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