#Linux

I needed to extract/generate a public ssh key from a java keystore so that the Java application could SFTP some files using public key authentication. The problem was that I couldn’t find any way of converting an ssl public key to an ssh public key. It seems that although ssl and ssh private keys are compatible, the public keys are not.

Like the fool I am, whilst messing about with user privileges in phpMyAdmin I managed to delete the root account. Suddenly I found myself with no access to any of my databases It took a while to figure out how to re-create the root@localhost user, so here’s how I did it.

I recently gave K9COPY a try, it’s supposed to be the Linux equivalent of DVDshrink for Windows. It certainly looked the part, but when I ran it with a disk I wanted to back up it ran for a short while and then crashed Looking at the output of dmesg revealed that the disk was having trouble reading the encrypted disk: `[235.097347] sr 5:0:0:0: [sr0] Add. Sense: Read of scrambled sector without authentication

I was converting a TV show I’d to DVD format using ffmpeg, but the resulting file had the wrong audio channel. At first I thought it had no audio at all, but then I noticed it had a voice over occasionally explaining what was happening; “so-n-so has just entered the room…”. It appears that ffmpeg had selected the wrong audio stream. For some reason, it had had selected the second audio stream instead of the first. The fix is simple enough, you can manually set the streams to use with the -map option. The command below works well for UK freeview.

The XEN developers ad community have been trying fr years to get DOM0 support into the Linux mainline kernel. On January 5th 2011 it finally happened when Linux kernel 2.6.37 was released. Okay, so it’s only basic support at this stage, but it does represent a significant milestone in the hypervisors history.

If you’ve ever had a collection of mp3 files that you want to burn to CD for playback in the car or archiving etc, you’ll likely know how annoying it can be when the collection of mp3 files is just a bit too big to fit on a CD. You end up having to remove a couple of tracks… While this is probably OK for music (there’s always a couple of tracks I’d skip anyway), it’s not so good for audio books and the like. One answer to the problem is to reduce the size of the mp3 files themselves. Be warned though that

Okay, so I often hear people (mainly at work) pronouncing Linux incorrectly, with an emphasis on the letter ‘I’, as you would in the word ‘light’ for example. Although this may sound more professional it really isn’t. I don’t know why it winds me up, but I do have to bite my tongue to stop myself from correcting people and sounding like the office nerd (which, now I think about it I probably am!).

To convert most video files into DVD compatible mpg files, mencoder is a good option. The following will convert to PAL widescreen format.

I’ve just installed the 64bit version of Ubuntu 9.04 onto my main desktop PC. Everything was going well until I wanted to print a document. No, my printer was correctly detected and when I clicked ‘print’ the printer burst into life as expected. But after printing about half of the first page the printer just stopped. My printer is a HP Deskjet F2100 series (F2180 to be precise). I tried everything, google didn’t throw up anything useful, I installed later HP drivers but noting fixed it. After a lot of head scratching ad experimenting I did notice something odd. The USB device as owned by a user I did not have permissions for. I wasn’t expecting this to be the cause of the problem because if it was due to permissions then surely the printer would not print at all?!? I was wrong, and adding myself to the group that owned the USB device has fixed it. As this seemed quite off the wall I thought I’d share…