The following will overlay overlay.png on top of output.png

mogrify -draw "image SrcOver 0,0 0,0 'overlay.png'" output.png

While this one will overlay overlay.png on top of input.png and save it as output.png

convert input.png -draw "image SrcOver 0,0 0,0 'overlay.png'" output.png

You can download imagemagick from http://www.imagemagick.org/

You can download imagemagick from http://www.imagemagick.org/

The following will replace all red (#FF0000) pixels with blue (#0000FF)

convert sourceimage.png -fill "#FF0000" -opaque "#0000FF" destimage.png

The following will allow you dto do this from a command prompt:

FOR /F "tokens=*" %G IN ('DIR /B /AD /S .svn') DO RMDIR /S /Q %G

Remember, if you’re doing it from a batch file, you’ll need to double up the percent signs, thus:

FOR /F "tokens=*" %%G IN ('DIR /B /AD /S .svn') DO RMDIR /S /Q %%G

Easy…

First, create a new user which you will log in as.
Make sure this user is explicitly denied access to all files and folders on the system.
Now, add the following ’special’ permissions to the directory you wish to make write only..

It turns out that the plugin makes a huge difference.

Resource usage comparison over two (highlighted) tests. Cache is OFF on the left, ON on the right.

I kept increasing the rate of requests until the Disk IO rate was the same for both tests. With the cache turned off, CPU usage went through the roof to 400% of my allocation while still only serving up pages at five megabits per second. With the cache enabled, CPU usage settled at 20% and the data rate peaked at over 45 Megabit/sec.

I’m very impressed with the results… It seems that with a moderate spec server, you’ll hit your disk and/or network limit before you run out of CPU or RAM.

Are your mail logs (/var/log/mail.log) showing nrcpts=0 ??

Make sure the sendmail_path in your php.ini file (/etc/php5/apache2/php.ini) is set up correctly.

It should probably be…

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sendmail_path = /usr/sbin/sendmail -t -i

Permalinks help people see the topic of a page before it’s visited and generally mean that search engines will rank them higher too.

OK, so you’re getting 404’s as soon as you enable permalinks other than the default?

Firstly, make sure mod_rewrite is loaded. The easiest way is to use the phpinfo() function. This can be done by creating a php file containing the following code:

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<?php
phpinfo();
?>

You can then check the output of the phpinfo() function to see if ‘mod_rewrite’ in enabled.

If mod_rewrite is not enabled, you will need to enable it on the command line by typing:

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a2enmod rewrite

You’ll then want to restart apache with

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/etc/init.d/apache2 restart

If this doesn’t fix the problem, browse to the root of your website and check if the file ‘.htaccess’ exists.
If it doesn’t, create one by typing

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touch .htaccess

Make sure the .htaccess file is writeable with

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chmod .htaccess 755

If it’s still not working, check your apache config files. The root directory of your website must have AllowOverride set to all. For example, in the file /etc/apache2/sites-available/sitename

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<Directory /srv/www/>
	AllowOverride All
</Directory>

Just make sure the AllowOverride is set to All. The other items should stay the same.

Restart apache and hopefully your 404 errors will be gone.

Tell me how it goes…..

I’m moving from my Windows Server 2003 physical co-located server to a Virtual Private Server (VPS) running Linux.

All of the websites have been transferred across, everything else is still to be moved over.

In the meantime, if you find any problems, or anything 404’s, please flick me an email at b…@john.geek.nz

This is the first major revision of DateTimeUTC where you can now add or subtract from the current date. This is very useful if you want yesterday’s date.

Get the latest version from here: DateTimeUTC

The main usage of the application is:

datetimeutc [-options]

Options:
-fFORMAT Set output format
-z Set output time to Local Time (Not UTC)
-help View full online help

Example formats:
yyyyMMddTHHmmssZ 20081121T100227Z
“yyyy-MM-dd HH:mm:ss UTC” 2008-11-21 10:02:27 UTC
“dd MMMM yyyy” 21 November 2008
ddd Fri
dddd Friday
fff (Milliseconds)

Use double quotes when the format includes a space
Use backslashes to escape reserved character

Now, to add or subtract from the time, the format of the option is:
-[timeunit][value]
[timeunit] is one of YMdHms for Year, Month, Day, hour, Minute or Second
[value] is an integer and can be positive or negative

The following will print the UTC time one day ago:
datetimeutc -fyyyyMMddTHHmmssZ -d-1

Do get the output into a batch file, try this:
for /f “usebackq” %%a in (`datetimeUTC.exe -fyyyyMMddTHHmmssZ`) do (set UTCdts=%%a%)
echo %UTCdts%

Job done

I render them in 512×256, 1024×512, 2048×1024 and 4096×2048 resolutions. The clouds information is obtained from weather satellites and is typically around three hours old.

I also use monthly map files so that the snow/ice on the planet is more realistic.

Check out my real time renders at http://www.john.geek.nz/earth/.