Most, if not all file systems, assign a universally unique identifier (UUID) which looks like a random hexadecimal string to each file system. On a Gentoo system, you can get an overview of all UUIDs detected using a simple ls -l /dev/disk/by-uuid, courtesy of the gentoo udev rules. Users can also assign a specific label to a file system, either when they create it (like mkfs.ext4 -L ROOT /dev/sda2) or afterwards (e2label /dev/sda2 ROOT). This is also not limited to the content file systems – you can also assign a label to a swap file system.

This information can then be used to uniquely identify the file system, even if you don’t know what the device file (/dev/sda2) is called. A huge advantage is for those devices that often change device file (removable media, but also SATA or SCSI disks on systems where the admin loves adding and removing disks ;-) as you can keep your fstab configuration static: the fstab file doesn’t need to be changed, even when the device files themselves change.

A simple fstab line (/dev/sda2 / ext4 defaults,noatime 0 0) can then easily be transformed to use the LABEL=”…” syntax (like LABEL=ROOT / ext4 defaults,noatime 0 0).

Some people might also think they can use this mechanism for their kernel boot parameter (like using root=LABEL=ROOT instead of root=/dev/sda2). Sadly, the Linux kernel doesn’t offer this functionality. It is possible, but only when you use an initramfs (which I don’t).

Apart from the iw addition, I’ve reorganized the sections on Software Management as it was becoming too crowded. I’ve also started a ChangeLog for those who want to track the changes to the document.

Now if anyone can recommend me a good spell- and grammar checker…

I must admit, I remain impressed.

Small changes have already been squeezed in in the Linux Sea document. A larger change (the use of the iw tools for wireless connectivity) is being investigated (sadly, my broadcom-sta device doesn’t support the new nl80211 API so the documentation change is slower to integrate than expected). I’m also planning to make some updates on the software management chapter as it is currently becoming quite crowded.

In the cvetool, most changes are bugfixes and output enhancements as expected. I’m not going to add more functionality now – I first want to get a stable 1.0 release out there. But first continue to squash bugs and add rules to the versions.dat file so that it is usable on various systems (release 0.4 is around the corner).

Note that it is still not finished (no spelling and grammar check done yet, still need to add some exercises, etc); once it is, I will tag the sources appropriately.

On the cvechecker state, it is also still under development, but progress is going nicely. Most of the work now is in updating the versions.dat file with information on how to obtain the current version of a package/tool. It is an easy activity – most of the work is in finding out how CVE entries would label a tool (what vendor and product name would be chosen) and because I am too lazy, I am currently only adding those that already have CVE entries assigned to them (so I can just take a look at the correct values).

It is also my first attempt at using autotools. Quite some overkill for such a small project, but why not. At least it allows me to try to do some new things here ;-)

Feedback is, as always, very much appreciated.

More exercises on the following chapters will follow soon.

Updates to the script include visual accept/reject of single-choice and multiple choice answers and improved support for Internet Explorer (which I don’t have at home to validate).

I do, and I found it quite difficult to keep the knowledge live without having to reread the things every now and then. For that purpose, I started writing a simple JavaScript/XML/XSL fileset that allowed me to present questions (randomly if necessary) from a structured set of questions. In the beginning, it was too simple to share (string matching) but quickly grew to something more elaborate: regular expression support, multiple string-answer support, in-paragraph answer boxes and single/multiple choice answers.

With this fileset in place, I can keep track of things I would most likely otherwise forget: just select the category which I want to take a test from, and start with a (lot of) random question(s).

I’ve decided to put this fileset online (including demo files) and will extend the demo file with questions regarding my book, Linux Sea, allowing readers of the book to take online tests after they’ve finished a chapter.