Monday 17 December 2012

Linux, Command line email and config errors.

I've been battling trying to send a command line email from an Ubuntu system.   It all looked like it was going, and the mails were being queued to send, but nothing ever actually went anywhere.

Checking the /var/log/mail.err file I see


 postfix/sendmail[23197]: fatal: open /etc/postfix/main.cf: No such file or directory

(and a bunch of other similar ones) 

One quick google later, and it turns out that, even though it was a clean install of the mail program, the config files didn't get written out properly. 

To fix it, I did 

sudo dpkg-reconfigure postfix

Which runs the setup that ran when mail was originally installed.   

The PostFix Configuration Wizard!
(check out the 1990s ANSI styling)

That seems to have fixed the problem, and all the mail that was queued came through. 

One to remember - so I thought I'd chuck it on t'blog. 


Friday 16 November 2012

MySQL and vanishing InnoDB engines

So, apparently, MySQL has an amazing ability to make InnoDB engines vanish.

If that sentence means nothing to you, I apologise, but this is going to be an exceptionally geeky post, even for me.

If you use MySQL with InnoDB tables, it seems that they can very easily stop working because the InnoDB engine just goes away. It can be for a number of reasons, but they all seem to revolve around the "ib_logfile" files.

If, for whatever reason, you change the size of the InnoDB log in the config, and don't delete the existing log file - MySQL will start perfectly happily, but you won't be able to access anything InnoDBish.   Similarly if the ib_logfile(s) get corrupted in anyway.

Doing a "show engines \G" in the MySQL prompt will show you what's wrong - there is no InnoDB engine running.

You won't get any error messages. No warnings will be displayed. The only clue will be when you try to access the table and it will give you a "No InnoDB engine" error.

The solution is to delete or move the existing ib_logfiles from the data folder, restart the MySQL service and it will create new ones.  Everything should now be back to normal.


Apparently this can also happen if the log file setting is too high and the memory can't be allocated - so that's worth keeping an eye on.

Monday 22 October 2012

Charge directly, not via hub..

Having an electronics background, I really should've realised this sooner - however - if you're using a USB data cable to charge your smartphone, and it seems to be taking forever - is it plugged into an unpowered, very cheap, USB hub?
Cheap USB Hub
"We need more power captain!"

Turns out mine was, and was taking about an hour for 1% of charge, because the power supplied by the hub is so little it was only just managing to supply more than the phone was using.

I plugged it directly into the USB port on the PC and it's gained 2% in 5 minutes.

Might be a useful tip, so figured I'd stick it on t'blog.

Monday 25 June 2012

Raspberry Pi - ordered

I have ordered a Raspberry Pi.

It would seem I have "up to 10 weeks" to get my brain (and workshop) in gear to think what I'm going to do with it.

Lots of cool basic ideas.  None of them have actually solidified into anything resembling a "plan" yet.

----------

Update - 13/8/2012 - still no Pi.

I bid on one on eBay, but it eventually went for over £100, which considering it was a bog-standard one without even the O/S card, seems a bit crazy-insane.

---------

Update #2 - 23/8/12 - Woohoo!!

"You have a shipment being sent from RS COMPONENTS LTD that is due to be despatched on 22/08/2012" Looks like it's on it's way!!

---------

Update #3 - 04/09/12 - ARRIVED

It arrived..   I haven't done anything with it yet as have been too busy, but I have lots of plans.

Wednesday 25 April 2012

Angry birds and mouldy Apples

This is a story of how my continuing quest to get Angry Birds Space on my iPod led me through a journey of rage, disappointment and finally, acceptance that everything is, in fact, just a bit crap.

dead ipod
I finally bit the bullet and updated my iPod touch. You may remember to do it from my Mac would basically require me to buy a new Mac, so I installed iTunes 10.6 on my PC, upgraded the iPod and got it running iOS 4.2.1

I tried installing Angry Birds Space again - the original reason for the upgrade - only to be told that it doesn't support that particular iPod HARDWARE because it needs better graphics capabilities..

A small red light began to blink in my brain as my rage inhibitor burnt out.

"You could've told me that....  "    I said quietly...

The skies darkened, the crackle of rage filled the air and everything fell eerily quiet. 

"...BEFORE I UPGRADED THE O/S!!!"  

Tuesday 10 April 2012

Parsing bookmark files using PHP and writing it out as an HTML link

Here's a code example of something I knocked together to import Windows .url shortcut files to a MySQL database on my home-server system that I'm building.

The shortcut files are actually just text, so you can read them really easily..  
They just contain a header, then the URL.. For example:

[InternetShortcut]
URL=http://www.hackerspace.co.uk


Here's a PHP code snippet... 


//  Create a function and give it the filename of the URL file.. 

function readurl($filename)
{

// Pull the .url off the end.. 
$filenamebits= explode(".url",$filename);

// Create a "Link Description" from the filename
$linkdesc=$filenamebits[0];

// Open the file to get at it's juicy contents
$file = fopen("$filename","r");

// Set up a counter
$linecount=0;

// Set up a "While there's still stuff in the file" loop
while (!feof($file) ) {

// Open the file and get stuff from it, line by line
$line_of_text = fgets($file);

// If you're on line number 1... 
if ($linecount==1)

// Explode the line of text into pieces
$pieces = explode("=", $line_of_text);

// Extract the bits we want and wrap it in some friendly HTML
$URLTOADD="<a href=\"$pieces[1]\">$linkdesc</a>";

// You can either then write this string out to the screen, or like I do, fire it 
// into a database for later use

}

// Increment the line count
$linecount++;

}

// Close the file. Otherwise the operating system gets cross. Probably. 
fclose($file);

}

Why I can't play Angry Birds Space.

I wanted to play Angry Birds Space.  It's a simple thing. Should've been a no-brainer.

I tried it on my iPod touch, but it doesn't have iOS 4, so I'm deemed not-worthy.  I can't upgrade to iOS 4 because to do that requires a newer version of iTunes than my Mac OS version will let me install.  I can't upgrade my Mac OS because it's an old Mac and won't RUN a newer version..   So, to play it on my iPod, I would need to buy a new Mac.
Not going to happen.

Or I could install iTunes on my Windows PC and struggle to sync my music over, and then struggle to get it to do anything because the Windows version of iTunes is just not very good. (Sorry)

So, I thought I'd try the Android version on my phone..  I went to the Google app store thing (or Google Play as it now appears to be called) and went to download it.  Glancing at the permissions made me stop in my tracks..

Thursday 22 March 2012

Dropbox, iOS and Time related problem!

So, I just tried to get a screenshot of Angry Birds Space telling me I couldn't install it because I needed iOS 4 on my iPod touch. Which I can't do easily for long, complex, stabby making reasons..

Anyway..  Tried to upload it to dropbox and it continually failed..   Which was odd.

I ended up unlinking the dropbox app on my ipod, and then relinking it. Only then did it tell me that it couldn't connect because my system clock was more than 10 days out of date.  (Due to a battery charge issue. Well, me not charging the battery for about 2 months, anyway)

Reset the date, tried dropbox again, and hey presto it works. Worth remembering.

The picture I was trying to transfer. Damn you old iPod. 

Monday 16 January 2012

Links of stuff and things

I've been pretty busy recently, so the weekly part of weekly links went out the window.   Still, here's some interesting stuff I've found recently..

HP give WebOS to OpenSource - Good plan. Could lead to some interesting alternative O/Ses for things.

Tron Derezzed music - played on floppy drives!

EZ-Robot - Upgrade your old robotic toys to something way more cool

How gaming can enhance real life - Very interesting article in New Scientist about how gaming reactions can spill into real life. It's pretty rare that an article like this doesn't pull in all the classic negative stereotypes.


Friday 13 January 2012

Turn the beep off!

Random, quick tip - I can't believe I didn't know this already, but it turns out you can turn off the annoying DOS style BEEP from a command prompt in Windows.

Open a command prompt.

Type
net stop beep

you should get a response of
The Beep service was stopped successfully.

To turn it back on -
net start beep. 

To test it type "echo [ctrl G]"  - which will look like


echo ^G

on screen.


Concatenating CSVs the easy way

I was recently asked how to 'merge' a few CSV files into one, and if there was a script or tool that could do that. Lets say you h...