Using Git locally within a Subversion branch

Posted on Thu 19 January 2012 in Tools • Tagged with git, subversion

I’m not a big fan of Subversion but I’m madly in love with Git! So much that when I have to use Subversion, I create a Git repository within my locally checked out Subversion branch. This is really easy to do, and only takes four simple steps:

  1. Navigate ...

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LVM recipe: determine which physical volume(s) a logical volume is located on

Posted on Thu 19 January 2012 in Sysadmin • Tagged with lvm, recipe

Run the lvs command as follows:

# lvs --segments -o +pe_ranges

The output should be something similar to this:

LV      VG   Attr   #Str Type   SSize   PE Ranges
data    data -wi-ao    1 linear   1.82t /dev/md4:0-476930
data    data -wi-ao    1 linear   1.36t /dev/md2:0-357701
homes   data -wi-a-    1 ...

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Node.js experimentation - a GitHub clone script

Posted on Thu 19 January 2012 in Coding • Tagged with async, git, node.js

Recently I wrote my first Node.js program! Yeah, yeah, I know! Late to the game and all that! But I thought it was time to catch up with the rest of the world. Better late than never, right? (Also, the program needed to parse JSON data, so JavaScript felt ...

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Strongly typed properties in Java vs C#

Posted on Thu 19 January 2012 in Coding • Tagged with delegate, generics, method group, csharp, java

The background for this post was that I needed to implement strongly typed properties in a C# project. With strongly typed property, I specifically mean a strongly typed version of public object GetProperty(string propertyName), where the property name is a constant (or name) of some sort, and the return ...

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Generic extension method with multiple constraints

Posted on Wed 18 January 2012 in Coding • Tagged with constraints, extension methods, generics

In a .NET project, I was coding an extension method for forms, and for various reasons I needed to call a form method which came from an interface. Instead of coding an ugly type check and subsequent type cast, I was happy to discover that I could simply create a ...

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Playing with Java annotation processing

Posted on Fri 06 January 2012 in Coding • Tagged with annotations, apt, Java, spi

I found Project Lombok via a Tweet, and was intrigued when I saw that a single annotation could trigger automatic code generation transparently during compilation of a source file. How do they do that?

Some digging lead me to discover Java’s annotation processing API, and how one can use ...

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Adventures in updating hard drive firmware

Posted on Fri 06 January 2012 in Sysadmin • Tagged with boot, firmware, iso, linux

I decided to update the firmware of two of my hard drives. The drives in question are both Seagate Barracuda 7200.11, model ST3500320AS, and smartctl gave me the following warning:

==> WARNING: There are known problems with these drives,
see the following Seagate web pages: ...

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Generator combined with with/using statement - Python vs C#

Posted on Fri 30 December 2011 in Coding • Tagged with c#, generator, Python

The other day, I tried to return a generator expression from within a with statement in Python, like so:


def readlines(fn):
    with open(fn) as fd: # <-- the with statement
        return (line for line in fd) # <-- the generator expression

if __name__ == "__main__":
    for line in readlines("/proc ...

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Certificate error when upgrading to Oneric

Posted on Fri 30 December 2011 in Sysadmin • Tagged with oneric, ubuntu

Just updated one of my Ubuntu servers to Oneric, and I noticed some error messages during the installation:

error adding /etc/ssl/certs/
error adding /etc/ssl/certs/
error adding /etc/ssl/certs/ca.pem

I found a solution in this forum post ...

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Getting network interfaces in Python

Posted on Fri 30 December 2011 in Sysadmin • Tagged with linux, network interfaces, Python

Here’s a small Python script/module I put together to list all network interfaces on the current server (tested on Linux only!) in a format that easily lets me convert between name, index and address of an interface.

The code is based on from pydlnadms, but I ...

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