I just set up one of my old computers up in the corner of the living room so that there’s nothing but the bare necessities there. I SSH into it and do my stuff and then get out. It’s a lot of fun, really. While setting up SSH, I discovered that you could login to that SSH server without using a password if you used a pair of keys to handle the login. I’ve already been using Seahorse for a while now to handle my GPG keys and I noticed it could create a pair of SSH keys too. So I went through the process and it was super simple. All I had to do was:

1. Go to Key » Create New Key…
2. Choose SSH key
3. Enter a description and go to the next step
4. Enter a passphrase twice
5. Allow it to set up the other computer by supplying my login details

That was all, and now I have paired-key authentication and don’t have to enter the password every time I log in to that computer. Hurray!

If you have a default install of Ubuntu and you enabled Desktop Effects you’ll have trouble when you try to play a video. The video itself will play just fine normally, but if you try to combine that with a couple of Compiz effects, like trying to make it a bit transparent or trying to move the video while it’s playing, or rotating the cube while the video is on you’ll get a blank screen, sometimes green, sometimes grey. The way to fix this is:

Totem:

The inbuilt player. Open a Terminal and copy paste the following command:
gstreamer-properties
Then change the default output plugin to X Window System (no xv)

mplayer:

The process is essentially the same, you change the output plugin to x11. It’ll be okay so long as you’re not using xv. If you’re using the command line interface just add -vo x11 to the end. So a command to play abc.avi would be:
mplayer abc.avi -vo x11
If you’re using the GUI, you can change the settings there.

If you’ve played around with installing a lot of distributions you’ve made a mistake atleast once, and broken your partition table. Or atleast I hope so, because I’ve done it more than my fair share of times. The most recent was when I was installing Ubuntu 7.10 64-bit and I crashed GPartEd while partitioning. My problem was that I already had four partitions [1] on the hard drive and I also wanted a swap partition but I made a mistake somewhere along the line and ended up with a logical partition outside of an extended partition. This is very bad stuff.

What happened next was terrifying, both GPartEd and Ubuntu’s ubiquity installer claimed the entire drive was empty. Now this is very bad, because there are files on this computer that I adore and would hate losing. I was just about ready to kill myself when I found a forum thread on the Ubuntu Forums[2] that mentioned testdisk. It’s in the universe repositories and you can get it by enabling Universe in System » Administration » Software Sources and then running:
sudo aptitude install testdisk
It also creates a backup of your partition table if you want. I had a broken one but I wanted more than one shot at it so I emailed myself the backup and got ready to put my hope to the test. When it happened it was almost anticlimactic, three menus later (all in a simple user friendly style) I had my partition table back! And all the data stored on the drive was accessible once more. I was incredibly happy about that, and made a small donation to the software author. The single most useful piece of software I’ve ever used on Linux.

[1] Ankit Chaturvedi on Partitions
[2] My Forum Thread with the problem.