All is relative…

At work, I am often busy with quite a few projects. Yet, at times, I have no outstanding tasks because all of my tasks can only start when an event has occurred (like a server which is made available, or a budget that is approved) or another task has finished.

To keep track of my work, I write an extremely simple task manager: an XML file (for the data), XSL file (for the rendering) and HTML/CSS file (to render and use the browsers’ XSL capabilities). I call it taskviewer due to lack of more imagination ;-)

It is a simple manager with no user interface for managing it at all – so you’ll need to edit the XML file yourself. However, the HTML/CSS file, together with the XSL file, renders the content of the XML file in such a way that you have a nice overview of your tasks.

It’s “features” are simple:

• keep track of events you are waiting for
• keep track of a tasks’ dependencies (events or other tasks)
• get an overview of tasks that can immediately start versus that are blocked, waiting for its dependencies to finish

There is an example available online with some hypothetical data.

If you know of a simple program (preferably java or one available for both Windows and Linux) that has similar features (especially tracking tasks depending on certain events), please do tell me. I’ve looked at tools like taskjuggler but couldn’t find one that remains simple yet has these features.

I know that repeatable password generators are less secure than random character generators. After all, if you want a strong password, you can simply perform head -c 8 /dev/urandom | mimencode to obtain a nice, random password string.

However, in certain cases you might want to generate passwords given a particular entry which always returns the same password. For instance, for low-profile web sites. Most people use mneumonics (such as username reversed and appended with domainname abbreviation to give an example) but mneumonics can be quite insecure, especially if you use a mneumonic that, once someone sees one of your passwords, he can deduce all passwords.

An example would be the above-given algorithm, which yields for the following sites:

bugs.gentoo.org, user foobar, password raboofbgo
forums.gentoo.org, user bleh, password helbfgo
www.sourceforge.net, user mynick, password kcinymwsn

I’m sure you can find the password for other sites I would show you, so this kind of passwords are not that secure.

Enter hex2passwd, a tool which generates (the same) password for the same input over and over again. With the tool you can make your mneumonic a bit more secure as it uses hashfunctions to create a pseudorandom sequence and a character mapping to convert the hash result into a possible password.

An example for the above sites / mneumonic would yield:

For bugs.gentoo.org, user foobar
$ echo raboofbgo | sha1sum | hex2passwd -n 8
XqXgOYce
For forums.gentoo.org, user bleh
$ echo helbfgo | sha1sum | hex2passwd -n 8
l8U.tdzg
For www.sourceforge.net, user mynick
$ echo kcinymwsn | sha1sum | hex2passwd -n 8
70z4Bu3k

Of course, the tool offers some more flexibility, such as choosing your own character maps or scrambling the maps before you use them. In any case, if you think such a tool is useful for you as well, don’t hesitate to download, compile and install it – it’s a simple C program, probably too ugly to show ;-)

As stated earlier, I’m now focusing on the existing content of my (work-in-progress) ebook called Linux Sea (PDF, HTML). I’m going to add more text where appropriate, add exercises to each chapter as well as references to online resources.

When that’s finished, I’ll probably be writing a chapter on installing Gentoo Linux as that’s a major end-user topic that isn’t discussed yet (but luckily, there’s still the Gentoo Handbook).

I’ve updated the chapter on graphical environments a bit to reflect how applications, window managers, X server and widget toolkits work together. Hopefully it isn’t a big lie that I wrote there ;-)

I’ll probably be doing a bit of clean ups the coming days before I start out with more chapters…

Some time ago I received a digital camera; however, due to diskspace shortage I need to clean up my home directory. One of the directories that eats most of my sectors is one where I store all my pictures.

I know I have a lot of duplicate pictures, pictures deduced from master pictures (lower resolution, some editing) and similar pictures (same scene taken 4 or 5 times with different camera settings, hoping to get at least one good shot) but managing them wasn’t easy.

I now played a bit with gqview and this tool seems to provide some features I find very interesting; one of them is the “find duplicates” where you can even search for pictures with “similar” content and I must say that it does work. Of course, nothing is perfect, but I’ve managed to clean up the picture directory so it works for me.