Linux-only installation on a 2006 Macbook using rEFInd

While installing Linux on a blank hard-disc drive is trivial on most PCs, it turned out not to be on a 2006 Macbook Core duo. I gave up on the idea that Linux must be able to boot directly from Apple’s UEFI, and used rEFInd instead. The peculiarities of this process are described below.

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Boot Linux from a USB flash drive on a Macbook

In order to install Linux on the replacement of a crashed hard-disc drive in a 2006 Macbook Core duo, I wanted to boot Linux from a USB flash drive in order to then install it. While this is trivial on most PCs, it turned out not to be on an old Macbook.

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Send a message to a KDE user from the command line

I have been looking for a way to notify KDE users that I’m tinkering with their system. Since I’m usually logged in remotely, knotify doesn’t work, complaining about $DISPLAY not being set. So far, I’ve only been able to find the partial solution below.

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Astrophotography with ImageMagick

I am not a very dedicated (or experienced) astrophotographer, but every now and then I feel like taking a photo of the sky. On high ISO and long exposures, you’ll find plenty of noise. Also, if you live as close to a city as I do, you’ll want to subtract background and correct for field distortions, to improve the (contrast-enhanced) images. Here is how to do that from the command line, using ImageMagick.

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Converting from HTML4 to HTML5 and CSS

I’m one of those people who write HTML in a text editor (either directly, or into a program which later generates the pages). Still, I felt the urge to pretend to be modern and decided to convert my HTML4 pages into HTML5. Since things are not that straightforward (e.g. the <center> tag must be replaced by different structures depending on whether it is wrapped around text or an image), I decided to list here what I puzzled together using Google.

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gitcheck: check all your git repositories for changes

One of the cool things about distributed version-control systems (VCSs) or source-control managers (SCMs) like bzr or git is that they don’t have to be distributed. Today, I stick virtually any text file I write into a (local) git repository, which means I have quite a number of them. Here’s the bash script I use to check them all for changes.

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Using and creating Gentoo Linux repositories using Layman

Gentoo Linux uses ebuild scripts to compile and install software packages. Ebuilds for many packages are available in the default portage repository. However, you may want to add your own ebuilds, for example to add additional packages to your system or to apply a patch to the source of a package. Using overlays with Layman is an efficient way to handle this on either one machine or a number of machines.

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Apache will not start without network connection on Gentoo Linux

After an update of openrc, the apache2 server on my laptop refused to start without a network connection.  Even if the network was up, but hadn’t obtained an ip address, the service wouldn’t start.

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git for coworkers

Would you like a coworker without experience with git to use your git repository?  Or are you that coworker who hasn’t used git before?  Here’s what you need to know.

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Erroneous gfortran warning of unused module variable when variable is only used in namelist

gfortran-4.7.2 -Wall gives a warning about unused module variables when those variables are only used in a namelist:
Warning: Unused module variable ‘x’ which has been explicitly imported at (1)
The warning goes away when the variable is used elsewhere.

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