Linux RedHat / CentOS / Fedora : Uninstall a package along with dependencies

If you’ve been wondering how to delete a package you mistakenly installed (or which is no longer needed) along with all its dependencies, here’s a neat way to achieve just that.

The idea is that whenever you use yum to perform some operation on packages, a transaction is created. If you installed a package along with its dependencies, then you can undo just that by undoing that transaction.

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Fedora 20 Linux + bitcoind : Setting up firewalld for running a full bitcoin node

If you feel like running a full bitcoin node on your Fedora Linux server (and it’s a great way to help the bitcoin network if you have spare capacity / bandwidth), you’ll need to update the firewalld rules in order to allow foreign nodes to connect to yours.

Here’s how…
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Docker 101 : Creating an Elasticsearch image

Creating an image in Docker is rather easy and well documented.

You start by editing a file which describes the image, then run a few commands, and voilĂ .

In this post we’ll cover how to create a very basic Docker image which will let us spawn elasticsearch instances very easily.

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Getting Spotify to run on Gentoo/Linux: A Gross and Cruel Hack

Spotify is a great way to listen to music. Unfortunately the official client only runs on Windows and Mac machines. There is an experimental unsupported client for linux, however it’s provided as a DEB (ubuntu/debian) package.

Here’s a gross hack for whom is desperate to get it working on Gentoo.
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Unix 101 : Showing non-printing characters in text files (ex : DOS files)

A non-printing character is a character which won’t actually get directly printed (or displayed) but rather interpreted. Such non-printing characters are for example line-feed or tabulation. The interpretation of those characters can differ from one system to the next. For example the line-feed character is different on Unix or DOS.

If you need an easy way to confirm that a text file is DOS or UNIX formatted (they differ with respect to the end of line character(s) for example) or if you wish to display normally non-printing characters of a text file, you can use the -vET command line switches of the cat utility.

As explained in the man page :

  • -v : will use the ^ and M- notation for control and multibytes characters
  • -E : will make ends of lines visible
  • -T : will make tabulations visible

For example : Continue reading Unix 101 : Showing non-printing characters in text files (ex : DOS files)

Gentoo + OpenVPN : getting things started in the correct order

I’m running an OpenVPN server, configured in bridging mode.

I had quite a bit of trouble getting OpenVPN to start after networking is up, but before the the bridge is setup so that the tap0 device, which is created by OpenVPN can be added to the bridge.

The solution is simpler : let the tap0 be automatically created and added to the bridge by Gentoo Linux, then start OpenVPN with a config file instructing to use the already created tap0 device.

This post shows the configuration snippets to get things started in the right order on Gentoo.
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