One Line Guitar Tuner

Every now and then I come across something which makes me marvel at the flexibility of Linux. This is one of these things.

I play guitar, and I’d previously written a small script to act as a guitar tuner. I generated some .ogg files of the correct pitch and then wrote a script to loop through them in sequence. “Pretty good”, I thought, “Clever Me.”

Then a few days ago I came across this little gem of a script.

for n in E2 A2 D3 G3 B3 E4;do play -n synth 4 pluck $n repeat 2;done

That’s it. Sheer brilliance. Of course you’ll need to install the sox package first.

Counting files in subdirectories.

ze countOK, it sounds simple, and it probably is if you’re sitting at your desktop with Gnome or KDE fired up. However if you’re looking on a server half way across the world, using the command line its not so easy.

There are a number of tools which are useful in finding out things about your filesystem. ls, du, df are three of them, but sometimes they just don’t give you the information you need. In my case I’m backing up a server to a remote location. The script was timing out becase I was trying to back up too many files at once, so I needed to find the number of files in each subdirectory.

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Linux Memory Usage Summary Script

I was having trouble with a webserver this week, which I’d just set up for a client. When it went live, it seemed OK initially, but when we left it overnight it curled up its toes and died. It was so dead that I couldn’t even ssh in to reboot it, so we had to do a remote reboot. Crunch.

Anyway, on getting it back up, I poked around in the logs and found that it was running out of memory, which it really shouldn’t do given that it was a fairly low load on the webserver, and only apache, mysql and php were running on it. I looked around the Interwebs and found an excellent resource called Troubleshooting Memory Usage, which gave me some pointers about how to rein in apache and stop it from eating up memory so quickly. Thanks!

Anyway on the page was a script for summarising memory usage, which I thought was a good idea, so i grabbed that one and adapted it to my own purposes. I thought I’d make the results available here, so feel free to grab it and adapt it to your own needs.

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PrimeTime Linux

I’ve been thinking of setting up a company to set people up with Open Source workplaces, and every year that goes past makes me think that the time is almost here.

There are a number of factors which are conspiring to make Linux a viable alternative:

  • The fact that Linux, via distributions such as Ubuntu, Mandriva, Suse et al, are now easy enough to install and intuitive enough for the Everyday User. I set my girlfriend up with an account on a spare laptop and just let her play. Soon enough she was asking for it on her laptop as well.
  • OpenOffice. Enough said. Hardly anyone uses the full feature set of Word, so why do we slavishly upgrade every time a new version comes out? Well actually we don’t …

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Trust Scanner Success

My girlfriend turned up this morning with her scanner, a Trust Flat Scan USB 19200. Its an old model from around 5-6 years ago, and she’d lost the driver disk. This was clearly a challenge for Linux …

I plugged the thing in (its a USB scanner, which pulls all its power from the USB bus) and the light went on. However the scanner application which comes with both PCLinuxOS and Ubuntu wouldn’t start up. Time for some investigation. I got a root terminal shell and tried poking around

lsusb showed that the scanner was recognised.

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