Category: Tips

Setting up a CA SSL certificate in hMailServer

I’m a big fan of hMailServer, but the documentation for setting up SSL certificates and the certification chain is a bit lacking. The easiest way to check if hMailServer is setup correctly is to use OpenSSL. openssl.exe s_client -showcerts -connect

1,500,000,000 the Epochening

Don’t forget that at 2:40am, 14 July 2017 (UTC) the Linux epoch will hit 1,500,000,000 (1.5 Gigaseconds). Visit to watch the excitement! It hit 1,000,000,000 back in September 2001 and it won’t hit 2,000,000,000 until May 2033.

dump1090 binary built for Raspberry Pi / Arm

If you’re after a binary of dump1090 for the Raspberry Pi without having to build it, here’s a compiled binary for you. I built it on Arch linux, but it also works on Raspbian, or likely any other Arm processor

iPhone templates for UI prototypes

I’ve recently started doing a lot of development for the iPhone and iPad and I wanted to be able to sketch layouts on paper. Now it’s one thing to draw a rough iPhone layout, but it’s another to actually have

Converting PDF files to HTML on Ubuntu

It’s very easy to convert PDFs to HTML on Ubuntu. The command is pdftohtml

Downloading routes from a GlobalSat DG-100 with gpsbabel on Linux

This is a GlobalSat DG-100 It’s an amazing piece of Kit, but the software that comes with it is absolutely rubbish. You can download all of the routes (and delete them from the unit) in one simple command with gpsbabel.

Stopping Javascript from resizing the window in Firefox

One of my pet hates on the internet is shopping sites which resize the window when you’re looking at a zoomed in image. Not all of us still use a windowed browser, in fact, most people now use a tabbed

Combining two images with ImageMagick

To combine two images of the same size with ImageMagick, you simply do the following: The following will overlay overlay.png on top of output.png mogrify -draw "image SrcOver 0,0 0,0 ‘overlay.png’" output.pngmogrify -draw "image SrcOver 0,0 0,0 ‘overlay.png’" output.png While

Selective colour replacement with imagemagick

Selective colour replacement is easy from the command line with imagemagick. You can download imagemagick from The following will replace all red (#FF0000) pixels with blue (#0000FF) convert sourceimage.png -fill "#FF0000" -opaque "#0000FF" destimage.pngconvert sourceimage.png -fill "#FF0000" -opaque "#0000FF"

Deleting folders recursively

I needed recursively delete folders named .svn within a directory structure. 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 %GFOR /F "tokens=*"