Copy Sparse Files with Rsync

Updating my backup script that is using rsync, I have just realized that without further options, rsync does not handle well copying sparse files (i.e. files that are for instance holding a file system and that just take the space needed by their actual size). A consequence is…

How to Know if a File on Linux is Sparse?

A sparse file is a file which does not take more space on disk than needed. Such a file is usually used to store a partition image on disk, for instance with a virtualization solution like Xen.

Sparse Files — Commands Overview

I was just checking which commands are supporting sparse files. I post hereafter a short overview of what I found out (working on Linux).

• Create a sparse file of 20 GiB: 
   dd if=/dev/zero of=foo bs=1 count=1 seek=20G

NFS Automount with Snow Leopard

Before upgrading to Snow Leopard, I was using the NFS automount capability of Mac OS X. It was a handy way for my laptop to connect to my home NAS server (a linux box running Ubuntu).

Better Keyboard Shortcuts for Mac X11 Apps

I have always found the integration of X11 apps in Mac OS X quite alright, apart from the fact that for a native Mac application you use the apple key for keyboard shortcut and for an X11 app you use the control key. So, for instance, if you want to copy…

Xen Virtualisation on a Hetzner Dedicated-Server

I have written a small howto regarding the installation of Xen on a Hetzner dedicated server DS3000. The host system — dom-0 in the Xen terminology — is running debian sarge with software RAID1 support while various guest systems (domU) equipped…

Ubuntu Nano Backspace Problem Fix

There is an annoying problem with Ubuntu. Using the command line editor nano, the backspace key acts sometimes as the delete key (deleting the first character on the right and not on the left).

You can fix this by adding the following line to your /etc/nanorc file:

set rebinddelete

Java Quiz of the Day

Java quiz of the day (easy): what gives

Object[] a = new Integer[]{};
List<Object> b = new ArrayList<Integer>();

Response: we get an exception on the second line:

Type mismatch: cannot convert from…

Using Passbook for Boarding a Flight

On my trip to Berlin for the Scala Days conference, I used Passbook for the first time to store my boarding pass. I thought it would be interesting to share this first paperless boarding experience with you.

Java Quiz of the Day II

What gives:

Integer a = 100, b = 100;
Integer c = 200, d = 200;
System.out.println( (a == b) == (c == d) ); // A

Response: counter intuitively, the program prints ‘false’ out. Integer in Java is a non-native class, where ‘==’ means…