State of X in experimental What happened since last month? The video drivers we were previously lacking were built against X Server 1.9, with a tiny exception: xserver-xorg-video-nouveau. This one is particularly annoying because the ABI is not stable, and it requires a particular version of the kernel to be usable. The same seems to happen with the nouveau part of the libdrm library. As a consequence, I ve demoted it from Depends to Recommends for the xserver-xorg-video-all metapackage. The same happened to the xserver-xorg-input-wacom driver (for the xserver-xorg-input-all metapackage this time), since it isn t maintained by debian-x@, and since it didn t look too bad to have it only recommended (after all, we re only targeting experimental right now). In addition, all drivers were updated to the last upstream releases. Bottom-line, the following is now possible on (at least) both amd64 and i386 architectures:

apt-get install -t experimental xserver-xorg

As a side note: Intel users probably want to upgrade their libdrm-intel1 package to 2.4.22-2 (in experimental as well), they could run into X.Org Bug #31443 otherwise. Dependency handling for X packages in Debian Previously, dependencies were quite fun:

• Drivers used to provide a given virtual package: xserver-xorg-input-$ABI and xserver-xorg-video-$ABI. One shall note that the ABI is evolving independently for input and video drivers, see SET_ABI_VERSION in server s hw/xfree86/common/xf86Module.h for curious people.
• The xserver-xorg metapackage depended on xserver-xorg-core (the server itself) with a minimal version, and on those virtual packages. More precisely, for example in the input case: xserver-xorg-input-all xserver-xorg-input-$ABI so that by default one gets everything for autodetection to work, but one can pick a specific driver instead.
• The drivers only depended on the server, with a minimal version as well.

So what did we do to ensure the server and drivers were all using the same ABI? When the server was updated to a new ABI, one had to add the previous virtual packages to Conflicts (and keep a list of all of them, yay!). Needless to say, asking a package manager to upgrade at a same time many packages (several dozens for all drivers) declaring conflicts, especially during a mass dist-upgrade from a stable release to the next stable was no fun. So what s the current situation now?

• xserver-xorg depends on a minimal server version, and on drivers. The alternatives are now written like this: xserver-xorg-input-all xorg-driver-input. Notice there s no ABI mentioned here anymore. It s just about having the server, at least an input driver, and at least a video driver.
• xserver-xorg-core now provides an input ABI and a video ABI. In experimental for example: xorg-input-abi-11.0, xorg-video-abi-8.0
• Drivers now depend on the ABI they were built against. For example, xserver-xorg-input-evdev in experimental depend on xorg-input-abi-11.0

So one might think everything is now fine, except there are some conflicts still declared, to ensure one can transition from packages using the former (bad) logic to the new state of affairs. And those conflicts were still causing headaches to package managers. Fortunately, David Kalnischkies came up with a proposal to replace Conflicts with Breaks, which turned out to ease things. Yatta! All of that is implemented in experimental. squeeze is the transition period where the metapackage stills the depends on xserver-xorg- input,video -$ABI virtual packages, but where drivers now depend on the appropriate server ABI. (Thanks to Alexander Kurtz for his feedback.)

I had been planning to write today about my great uncle Milt Goerzen. Milt passed away last Thursday after a long struggle with dementia, and his funeral was this morning. I was there, and was inspired by a few things I heard. But that will have to wait, because today brought one of those few moments in life that s a sense of an impending possible great loss. I can remember two others: one was when Terah passed out, and the other was when we heard that our place was on fire and our house had burned down (it turned out the house hadn t, but much of the rest had). I got a call during Milt s funeral. I didn t answer because I was, well, at a funeral, and the phone was on vibrate. When I had the chance to check the voicemail, it went something like this: I think we have an emergency with Jacob. He got run over by a tractor. He says he s OK, but I m taking him to the doctor right now. I tried to return the call, but cell phone reception wasn t cooperating. The most I got was he s OK . It s hard to describe how a moment like that feels. My mind jumped to telling Jacob I love you , and how lately when he hears that, he will snuggle in for a big hug, and say, Dad, I love you toooooooooo! On the one hand, I heard the he s OK part, and on the other hand I couldn t forget the tractor running over him part, and my mind leapt at the worst. It turns out that, while I was at the funeral, Jacob had been standing on his usual spot on the tractor, sort of to the side of the driver. He was enjoying himself like usual. The tractor hit a large hole that wasn t really visible. The combination of the jolt and the dip the tractor took towards Jacob s side knocked him off and he went directly under the big rear wheel before the tractor could be brought to a stop. I caught up with him and his grandpa after he had seen the doctor and just as he was being admitted to the hospital. He saw me and crawled over, making his sort of sad and scared sound he sometimes doesn t want to verbalize things when he s in that mood. I held him close and he seemed to appreciate it. He had to have blood drawn, and he was scared of that. I remembered his inquisitive mind, and reminded him how much he liked watching the tube fill up with blood last time he had a blood test (which he calls a blood shot ). That wasn t helping, until the actual blood test started. He cried when the needle went in, but then calmed down as the nurse, getting into the act, pointed out that there was blood filling up the tube. Hmmm! said Jacob. Then she gave him a band-aid. It has an airplane, said the nurse. Um-hmm! said Jacob. I pointed out that it looked like the airplane we were on when we flew home from New York. Jacob got a big smile and said, Yes, it IS that one! He got a sticker there too. Then it was off for an x-ray to check for broken bones and a CT scan to check for internal injuries the tractor had gone right over his abdomen. He had to get an IV at the CT scan, which he certainly didn t like. After it happened, however, he found it very interesting especially when the nurses explained that they would give him a drink through the hose attached to his hand. After that, we went to his room, with orders for him not to eat or drink anything until it was clear he didn t have digestive problems. While we waited at various steps along the way, Jacob wanted to sit on my lap and watch train videos on YouTube on my phone. He loves train videos, and brought my phone s battery nearly to depletion through the course of the afternoon. Jacob eventually seemed to get back to a bit of his usual self. At one point, while Terah had made a run home to pack an overnight bag and grandpa ran some errands of his own, Jacob wanted to leave the room. He had gone exploring in the hospital with me before: when Oliver was born, and when Terah had her thyroid surgery. So this was something he just associated with the hospital. That and lemonade, which is free any time of the day or night in the cafeteria. So we went exploring, even ventured outside into a courtyard for a bit. He was walking fast and seemed good. We had several visitors: grandparents and his aunt and uncle. Jacob got a stuffed rabbit and a colorful bug box with windows (for putting bugs inside for observation). Eventually the doctor came by and gave us the results: the x-rays showed no problems. The labs showed some elevated liver enzymes, which he expected, but no serious trouble. The CT showed contusions on his lung and bruising on his heart which would heal completely in time. He allowed Jacob to have a liquid supper (so I quickly got him the lemonade he had been wanting while the nurses got him some Jello). The doctor examined Jacob, pushing at various places, asking Does it hurt here? No. Does it hurt here? No. Here? No. Are you hungry? Yes. Does it hurt here? No. He gave me a look that said: really? It doesn t hurt ANYWHERE? What could I do but shrug my shoulders? Jacob has some abrasions on his face, arms, and back, which will probably eventually hurt (and sure enough, about 10 minutes later he started getting a little pain when he tried to move, which the doctor checked out) Then the doctor said, I hope you know you have a walking miracle today. This is just amazing. You have some thanking to whatever guardian angels you like tonight all I can say about this is that the Lord must have had some other plan for him. There s no way he could have survived that. Jacob s doctor is one that we really respect: he s scientific in his analysis, cites studies as a matter of routine, doesn t prescribe antibiotics for things that he knows they have a small chance of helping, is common-sense about not over-treating things and yet always engaged in an emergency. That little speech from him was something I d never expected to hear from him. He went on to add that I always visit my sickest patients first. You were my last visit this evening, so that should tell you something. Any other kid as healthy as he is, I might discharge already but I m just not justified doing that with a boy that s, well, been driven over by a tractor this morning. He also wanted to monitor Jacob s progress throughout the coming day, especially his digestive system. They wanted to measure his urine output, which he, predictably, found to be very interesting. Terah said I think it is about 150 ml. Jacob said, No mom, it is closer to the two hundred line. Me: Since when does Jacob know about the number 200? Terah: I don t know . he s 4, where would he have gotten it? Between that, and using every opportunity to tell people that there were not one but TWO red light switches in the x-ray room, Jacob s definitely himself in some ways already. So, that feeling of some impeding great loss is gone, replaced by being more than a bit overwhelmed by how fortunate we were today. We also appreciate all the help we ve had with Jacob and Oliver today.

Now that we have KMS, it happens things go bad enough that when X goes down, one can no longer access any console to see what happened. Mainly, one can distinguish between two cases.

• The good one: the machine is still accessible over the network. Unfortunately, that requires having a spare machine to ssh into the first machine, but that means one can run dmesg, look into X logs, possibly run X inside gdb and see where it breaks (because glibc s backtrace isn t exactly an excellent tool to get the idea of what s going on and that s the tool used in X to print a backtrace in the log through a signal handler).
• The bad one: the machine is no longer accessible over the network. Likely, the kernel is in such a bad shape that one is never going to know what happened. Usually, writing logs to disc didn t happen, so logs won t magically show up at next reboot.

I m going to discuss the second case. There s a nice tool in the kernel which makes it possible to send kernel logs over the network. It s called netconsole. As far as limitations are concerned, one shall note that it s UDP only, and over Ethernet (in other words: no wireless). The good news is that it can usually make the last crucial lines available. Let s call the crashy machine a patient and the logging machine a doctor. One should keep in mind that if something goes wrong while configuring the netconsole module, it can be unloaded at anytime through:

sudo modprobe -r netconsole

Easy case: on a local network Here s an example: Patient s IP is 192.168.0.1, doctor's IP is 192.168.0.2. Doctor setup What one needs on the receiving side: only netcat. A tiny warning, there are several implementations. Here s the appropriate syntax:

# netcat-traditional:
nc -l -u -p 6666   tee ~/netconsole.log
# netcat-openbsd:
nc -l -u 6666   tee ~/netconsole.log

The nc command is handled through the alternatives system, one can use update-alternative --config nc to pick the appropriate one if several netcat-* packages are installed. To list the current one, an easy way is readlink -f $(which nc). Using tee means that incoming messages are going to be printed, both to the standard output and to the specified file. Running as non-privileged user is sufficient. Patient setup Now, to have the patient send stuff to the doctor, a simple modprobe is needed:

sudo modprobe netconsole netconsole=@/,6666@192.168.0.2/

What happens here? One requests the netconsole module to be loaded, and one specifies the parameters. Details can be read in the Linux kernel documentation (Documentation/networking/netconsole.txt), but concentrating on the points of interest here:

• 192.168.0.2: The doctor s IP.
• 6666: The UDP port to which packets are sent. 6666 is the default and can be omitted.

That s all! On the doctor side, one should see something along those lines:

[2920549.188090] console [netcon0] enabled
[2920549.188102] netconsole: network logging started

Slightly harder case: over internet Because one might not have a second machine handy, it s also possible to go through a router and send stuff across the internet. Here s an example: Patient s IP is 192.168.0.1, connecting to internet through a router, which IP is 192.168.0.254. The doctor, available over the internet, is 192.0.32.10. Doctor setup Exactly the same as in the previous case. The main issue one can run into is firewalls at this point. That s why one may want to switch from the default 6666 port to another one which wouldn t be filtered. One can think of 53 (DNS), but that means running nc as root since it s a privileged port (below 1024). Patient setup Routing is also possible, but that requires an extra parameter: the MAC address of the router. To obtain it, one can use the arp command:

/usr/sbin/arp 192.168.0.254

Supposing it returned the 01:02:03:04:05:06 address, loading the module becomes:

sudo modprobe netconsole netconsole=@/,6666@192.0.32.10/01:02:03:04:05:06

Now, if you re running into firewall-related issues, you can change the source for the UDP packets. The default is 6665, but assuming you want to send from an unfiltered 1234 port, that becomes:

sudo modprobe netconsole netconsole=1234@/,6666@192.0.32.10/01:02:03:04:05:06

Last week, I worked on my Google Maps for Emacs extension. I've introduced a new format handling for locations which include the longitude and latitude. The initial format was just a string describing the location, which was obviously too limited. It now prints coordinates of the different elements when the mouse is over the map, with other information. It also center the map on M-x google-maps and set a default zoom level. This is something which was not set because it's not a good idea to set center coordinates in order to see all points on the map automatically. But you can still remove the centering by pressing "C". On the other hand, setting it automatically allows to move the map easily, and I think that what most users want to do. I've also added a "place my home on the map" feature, accessible by pressing "h" on any map. That adds a marker according to the location set in Emacs using the calendar- variables. This feature is also available under Org by pressing C-u C-c M-l, which shows the location of your appointment with your home on the map too. Finally, you also get caching so it does not request images you already seen, which makes the moving nicer and faster to use, and prompt history.

So, with the GNASH_OPTIONS=writelauncher hint from last time, you have got a script which runs gnash. It is still running a remote SWF file, though - you want to modify that file to isolate a test case, and for that it will need to be on the local filesystem. First, look in the gnash-debug-1.sh script to find the URL for the SWF, and download it. It's the last option passed to gnash. In order to convince the file that it's still being served from the web server, you now need to swap the '-U' option in the gnash command line for a '-u'. This is enough for gnash 0.8.8 to play the file. Unfortunately, if you are running current git master, this does not work. You also need to feed the SWF from standard input to gnash - i.e. use '-' as the last option, and redirect the SWF file to the gnash command:

/path/to/gtk-gnash -u http://some/url [more options] '-' < downloaded.swf

If any of this is documented, I'm buggered if I can find it.

Last week I was on my first Ubuntu Developer Summit (UDS-N), I wanted to attended this summit for couple of reasons: 1. Developer, I m part of Debian Java, working on Eclipse IDE, and as you re developing Debian, you re automatically developing Ubuntu, no? 2. DebConf11 main organizer, I really wanted to see how it s all done on corporate level, for instance we re going with hotels instead of student dorms and so on. 3. Migration to Linux infrastructure, make contacts and have some talks on this topic, because after DebConf11 in Bosnia a lot of institution will most probably open doors to open solutions such as Linux. I went to this summit without any expectations or plans, just said I ll play it by ear. This years UDS was held in Orlando, Florida before Orlando I was planning to stay in NYC for couple of days, therefor my whole plan was to get to NYC, then Orlando then head back home I NYC I spent couple of days here with my cousins and friends, as always NYC never fails to surprise me, and I ll always stop by even if it s only for couple of days I wanted to meet up with couple of Debian people as well, but unfortunately my schedule was too tight so Caribe Royale, Orlando Please note that this whole trip was crazy (in a good way) starting from Sarajevo; on my flight from NYC to Orlando I see a guy that s sitting in front of me is wearing Canonical Landscape tshirt, I approach him and it turns he was Jamu Kakar working on Landscape. Since my luggage was late we had conversations from Debian over Ubuntu to Java to everything pretty much. While we were still at the airport, we bump into two more people going to UDS. As we got to hotel, same moment we walked out of cab there he was Jorge Castro, was he there just to smoke a cigarette or whatever doesn t even matter, what matters is that even before walking into hotel building I knew where reception, my tower and bar was, everything I needed to know at that moment Hotel where everything was held was Caribe Royale and even though I looked at their website I thought there was no way it s all going to be that nice, to my delight it was exact replica. Place is All-Suite Hotel and Convention Center , which meant that both accomodation, venue and everything else was in one place which is 15 minutes later after I checked in, I was at a bar talking to Jim Baker about Java, Jython and Python, exact things I wanted to talk about at that given moment. What I said in these last couple of paragraphs sounds pretty cool eh? Well to me this whole UDS was just like this, everybody was so accessible and open for discussion, from Jono Bacon walking around offering candy to UDS reception staff Michelle, Marianna and others who were always there whether you had a complaint, problem or a praise. I really should stop mentioning names, because I ll forget somebody, and since it s just not fair because I had a feeling everybody was just there for you, whatever it was you needed. Ubuntu Developer Summit (UDS-N) Ubuntu, Debian, DebConf, differences? Even though I said I ll play it by ear, from very beginning I thought I d be complete outsider, being part of Debian and all. Quite contrary, I was everything but outsider, and even more there was plenty of Debian people there, including current DPL Stefano Zacchiroli, Colin Watson, Riku Voipio just to name few. There was also a Debian Healt Check plenary. But overall, there are differences between DebConf and UDS. One of the things is that you can attend UDS remotely I m not sure how much is this doable on DebConf, but then again vast differences are that UDS is filled with BOF s (as we would call it in Debian) meetings of different teams, I attended a lot of these, and most of them end with some kind of conclusion. While each day there was (only?) an hour of lectures on various topics, which on DebConf we would characterize maybe even as speed talks . However, everything was high paced, and it all ended up on You think that s a problem? How do you think we could solve it? . I had a feeling even if I didn t say something out loud that someone would hear me and approach me to discuss it. Everything was straight forward, all in goal to resolve certain issue or a problem, which I absolutely loved. Fun It wasn t all work, even though Orlando doesn t seem to be my kind of city from what I saw, it s way too magical for my taste There was a lot of places where you could go to enjoy yourself. Good people at Canonical even offered me free ticket to Disney World, there was a lot of destinations to visit and transpiration was also organized by Canonical. Unfortunately I missed the notorious UDS party on Friday because I had to head home early, but possibly I ll make it next year Even though, hotel was that great and to be honest you didn t have to leave to look for party. My favorite was Universal City Walk, one night I decided to go to see Blue Man Group, best part of it was that I got pulled up on stage by one of the members and was part of one of the acts! This is definitely something everyone should see during his life, one moment you re laughing like a lunatic, while other moment you re just having goose bumps from the performance itself. Amazing stuff. After all I wrote here along with the pictures, is there even anything else I need to say? I believe that even if I didn t play it by ear, this whole trip would exceed all my expectations in every possible sense. Because that s really what happened, those three reasons I was going to UDS for? Far more happened than that. All I can say in the end is that I ll move closer to having a part in Ubuntu development, and yea, I ll try to be regular on UDS from now on See you in Budapest? If all these photos weren t enough, you can find official group photo as well as personal set of photos can be found on: UDS-N photos by 2010 Sean Sosik-Hamor

Debian mailing lists' standard policy is to allow posts from unsubscribed users. That of course fits our standards for opened development but has the drawback of allowing a lot of spam to reach our mailing lists. This spam also clutters the mailing lists archives. However, 1.5 years ago, listmasters established a well-working system to clean out spam from the mailing lists. It basically works in four steps:

1. first, spam can be "reported" by anyone meeting it. While you are reading the mailing lists, reporting spam is as simple as bouncing the offending mail to a dedicated address: report-listspam@lists.debian.org. I, for instance, use a mutt macro to set ESC-L as a "report spam" hotkey. Spam can also be reported when browsing the mailing lists archives and clicking on the "Report as spam" button;
2. when a given mail has been reported as spam more than five times, it is then "nominated" for review;
3. nominated mails must the be reviewed by volunteers in order to confirm they really are spam. The review algorithm is complex but, in short, when a mail has been confirmed as spam by 3 reviewers without being qualified as "ham" by anyone else, then it is considered spam;
4. such mails are then removed from the mailing lists archives.

Steps 2 and 4 are performed by a weekly script that runs on Sunday mornings (5:00 UTC, IIRC) How can you help? Process nominated spam We need more reviewers for step 3. At this moment 2 people are doing this on a regular basis (every Sunday with the morning coffee). Some others are working on this in a less frequent way. It seems that 1 or 2 more regulars reviewers would guarantee that we can cope with the nominated spam incoming flow. Only Debian developers can do that step. They should read instructions, ask for a password, then start reviewing. The first 1 or 2 people joining this will have a quite big amount of nominated spam to process, for their first effort. However, as most of these have been classified as spam by at least the two people doing this for months....the amount will slowly decrease. I, for instance, now only spend 5-10 minutes reviewing the nominated mails every week. Report spam Everybody can work on reporting spam. You can start by doing this on mailing lists you read by just bouncing spams to the spam report address; If you want to do more, you can join existing spam cleaning efforts, such as the one running for debian-boot or the one running in debian-l10n-french (the latter probably more for French speakers). Or you can of course start a similar effort for your pet list. To be efficient, this effort needs to gather 5-6 people who will process the mailing lists archives systematically. Let's clean out these archives!

For some reason, 60G of free space on my notebook suddenly turned into 60G of movies. Bownian motion, perhaps. Unfortunately, in this particular case, I absolutely don't like to let a movie (or book, for that matter) unfinished, so I watched Fear and Loathing in Las Vegas (directed by Terry Gilliam, starring Johnny Depp; so far, so good) from start to finish. After the first half hour I started wondering if the plot is going to start. The reptile party in the hotel lobby was a short entertaining interlude, but to the end, no plot manifests. I'm left wondering what this was all about. Quantum of Solace on the other hand is good entertainment. Probably not one of the best, but still worth watching if you like her majesty's secret agent. Going back to movies I've seen before is something I like to do as well, so having another evening in company with the unforgettable Leon (the professional) was time well spent. I didn't give up on Terry Gilliam yet and met The Fisher King. While the story is completely different, it does feel a bit similar to 12 Monkeys in terms of set design and atmosphere. Speaking of Terry Gilliam: I'm curious how his current attempt at The Man Who Killed Don Quixote turns out; so far I've only seen him losing this movie in the documentary about the aborted last attempt: Lost in La Mancha. On the funny side, Dogma and especially The Wedding Crashers were worth watching. If you have to pick one, it's the latter one. Dogma feels a bit forced in some places. Returning back to the opening theme: seeing Inland Empire was another evening that left me confused. The main story is interesting enough, but I have to admit that I just couldn't follow where all the other sub plots tie in, or if they even are supposed to. And I'm not only talking about the rabbit family (those felt a bit like the Middle of the Film in The Meaning of Life and were quite in order.)

Hello I m a Perl author working on a Debian unstable system. The great thing about Debian is that a lot of Perl modules are available though Debian packages. I follow Debian way of life to the point that I no longer install my modules (under development) with sudo make install (or its Module::Build equivalent). I ve often been bitten by weird test errors due to old version of module lingering in /usr/local. Now, I always create Debian package of my modules under development with dh-make-perl. This way, I avoid installing Perl module in /usr/local and my developement versions are cleaned up when actual package are availalble through Debian unstable. () This method has an unfortunate side effect: I never test installation the CPAN way. And Config::Model did fail to install with CPANPLUS. Now here s a way to create a barebone Debian chroot with cowbuilder to test CPANPLUS installation. First create a new chroot: $ sudo cowbuilder --create --distribution sid

Loging into this chroot (the bindmount option is necessary for cpanp to work correctly) : $ sudo cowbuilder --login --bindmounts /dev

In the chroot: Run cpan to configure CPAN: # cpan

Hit return to configure CPAN automatically. Then install your module: # cpanp i Config::Model

Or, if your module is not yet uploaded: # cpanp i http://<path-to-tar.gz>

Once you quit, the chroot is restored to its barebone state. Et voila. I tested full installation with dependencies the CPAN way without mucking up my system. Many thanks to Christian Kuelker of Cipux project for his comments that enable me to improve Config::Model All the best

In the comments of the article explaining how to generate different dependencies on Debian and Ubuntu with a common source package, I got asked if it was possible to apply a patch only in some distribution. And indeed it is. The source package format 3.0 (quilt) has a neat feature for this. Instead of unconditionally using debian/patches/series to look up patches, dpkg-source first tries to use debian/patches/vendor.series (where vendor is ubuntu, debian, etc.). Note that dpkg-source does not stack patches from multiple series file, it uses a single series file, the first that exists. So what s the best way to use this? Debian should always provide debian/patches/series, they are supposed to provide the default set of patches to use. Any derivative cooperating with Debian can maintain their own series files within the common VCS repository used for package maintenance. They can drop Debian-specific patches (say branding patches for example), and they can add their own on top of the remaining Debian patches. It s worth noting that it s the job of the maintainers to keep both series files in sync when needed. dpkg-source offers no way to have stacked series files (or dependencies between them). If you want to use quilt to edit an alternate series file, you can temporarily set the QUILT_SERIES environment variable to vendor.series . Just make sure to start from a clean state, i.e. no patches applied. Otherwise quilt will be confused by the sudden mismatch between the series file and its internal data (stored in the .pc directory).

Found it useful? Click here to see how you can encourage me to provide more articles like this one.

No comment Support my work

It is widely considered good style to include

set -e

near the beginning of a shell script so that it aborts when there is an uncaught error. The Debian policy also recommends this.

Unfortunately, this doesn't work in pipelines. So if you have something like

some_command   sed '...'

a failure of some_command won't be recognized.

By default, the return status of a pipeline is the return status of the last command. So that would be the sed command above, which is usually not the failure candidate you're worried about. Also, the definition of set -e is to exit immediately if the return status of the last pipeline is nonzero, so the exit status of some_command isn't considered there.

Fortunately, there is a straightforward solution, which might not be very well known. Use

set -o pipefail

With pipefail, the return status of a pipeline is "the value of the last (rightmost) command to exit with a non-zero status, or zero if all commands exit successfully". So if some_command fails, the whole pipeline fails, and set -e kicks in. So you need to use set -o pipefail and set -e together to get this effect.

This only works in bash, so if you're trying to write scripts that conform to POSIX or some other standard, you can't use it. (There are usually other ways to discover failures in pipelines in other shells, but none are as simple as this one, it appears.) But if you are writing bash anyway, you should definitely use it. And if you're not using bash but use a lot of pipelines in your scripts, you should perhaps consider using bash.

(Hmm, it looks like there could be a number of latent bugs in the existing Debian package maintainer scripts, because this issue appears to be widely ignored.)

My fellow Republicans and I got a nice early Diwali present on Tuesday. ~65 seats in the House ~6 in the senate, ~18 governorships and control of ~20 state legislatures. (Some races haven't been formally called yet.) A few disappointments though. no majority in the Senate and Harry Reid and Barney Frank were not defeated. Still overall its an election to celebrate. Here are a few thoughts. The Election System Is An Embarassment Once again there are several races where the outcome is in doubt because of technical problems with voting. Whatever politics we have, can we agree that it is damn stupid that we still can't get something as simple as counting ballots right? Prediction: The 2012 Republican presidential candidate will come from the Tea Party. While I may be a Republican, I am also a Cosmopolitan East Coast Elitist so the Tea Party didn't move me much. There were a couple of cases (NY and DE atleast) where their candidates were subpar and cost us victory but the best of the new Republicans also came out of this movement. I would rather vote for one of them than Romney, Huckabee, McCain, Gingrich etc. (With the exception of Sarah Palin who is just too polarizing I'm afraid.) The Tea Party itself will subside in a few years as all populist movements do. (Ask the Hope'n'changers.) Young People Are Dumb Part of leftist mythology is the idea that one day "the kids" are going to rise up against the mean old corporate overlords. It ain't going to happen. There was a huge upsurge in first time voters in 2008 but that was because Obama was a novelty act not because they had suddenly discovered the merits of Keynesianism. Now Obama is old and busted so they won't vote anymore. (Not until they have kids and a mortgage sometime in the future.) They'll spend time make cool ironic signs for the Rally to Promote Comedy Central but even the prospect of legalizing pot won't get them to the polling booths in sufficient numbers to defeat the oldies. Why? Because young people are dumb. Prediction: War With Iran If you're President Obama what do you do now? Bipartisanship? Yeah right. Look at what happened to Rep. Cao of Louisiana, the only Republican to vote for Obamacare and one of only two GOP congressmen to lose on Tuesday. Obama actively campaigned for his challenger. Any of the new Republicans who try and compromise with the President will end up under the bus sooner or later as they well know. The President could go full retard with the socialism (progressivism, liberalism whatever. It's all the same.) All his initiatives will be shot down but he can claim to be a martyr to the party of No. (Who will be joined in the Senate by Lieberman and whatever centrist Democrats who are up for reelection in 2012.) But this seems to be the path to a one-term presidency to me. Maybe that's what he wants. He could retire comfortably to the deanship of some Ivy League law school and make a lucrative killing on the rubber chicken circuit. But lets assume he wants to get back in the White House in 2012. One way to get back in touch with the voters is to start getting serious about foreign policy which has either been a joke (Remember the reset button?) a travesty or just copied from the Bush administration. In particular the Obama administration has completely failed in stopping Iran from gaining nuclear technology, sponsoring terrorism in Iraq, Afghanistan and Lebanon, and oppressing its own people. War with Iran would enhance his standing with Conservatives (hey it works for me!) most liberals would go along with it and the extreme Code Pink type loonies can safely be ignored. I say it happens before November 2012.

During my recent trip to Massachusetts for CalConnect XIX I passed back via New York, surfing a few nights on the couch at the Washington Cube Garden¹. This was just enough time for my new Davis VantagePro2 to arrive by UPS ground (phew!) causing me much consternation, as the box was about twice as wide as I expected it to be. On opening it I discovered that the reason for the size was the physical dimensions of the rain gauge, leading me to realise that I had actually bought exactly what I wanted: a high quality weather station. Also leading me to wonder how the hell I was going to get it halfway around the world with me the next day. Unfortunately that extra wide carrying case was in no way going to fit inside my suitcase. Fortunately it came with a handle. And those wonderful people at Air New Zealand gave me a Koru Gold upgrade for a 50th birthday present, so it was time to put it to the test... Travelling on the subway out to JFK was it's own little adventure, but I made it out to terminal 5 and wandered around a bit before concluding I needed to be in terminal 7. Once I was in the right place I found the fancy people's check in counter and the nice lady there was only too happy for me to carry it to New Zealand, though she did aver that perhaps the security scanners would be dubious. Not a hitch there though: I guess they're used to letting everything through that's not specifically denied, so weather stations are fine because nobody would be silly enough to even think of doing that... Being Koru Gold really helped at this point though, because it enabled me to queue jump use the priority boarding line when getting onto the plane, and every airline in the US seems to have gone all-out for this "checked baggage costs more" approach, so the planes all fly with empty baggage holds and totally overstuffed overhead lockers. If this progresses I shouldn't wonder that the planes will get so top-heavy they roll over, but through the miracles of priority boarding I was able to commandeer all the locker space I needed before anyone else had even made it past row 40. I confess that I was a little worried that it wouldn't be quite such plain sailing getting through LAX. I mean we all know what reputation this delightful little exit port has. In the event it was totally anitclimactic. If it has a handle on it, and it's about the same size and shape as a largish carryon then it's fine. There have been no recorded stabbings with wind vanes anyway - at least on aeroplanes - so clearly they are perfectly safe. Finally back in my country of birth, thinking I was home free, I breathed a sigh of relief transferred my bags and nipped off to the Koru lounge for a much needed shower and change of clothes after I snuck the station through another scanner. By now the handle had broken, so it was looking decidedly more 'box' like and less 'carryon' like, and when I eventually rolled up at the gate with my boarding pass the attendant made a valiant attempt to relieve me of it, but she was too slow and I danced around her and swanned up the gangway to take my seat. I was slow, this time, having missed the first boarding call, and all overhead lockers were crammed full. There was no seat in front of me to put the weather station under. Fortunately a nearby cupboard proved fit for purpose and it was secreted there and we were underway. At this point the guy two seats over said "didn't I see that weather station in New York?". Of course being bright yellow does make it a little conspicuous I guess, and I'm not renowned for my own inconspicuousness myself. So that's how I got my new weather station home, and you can see right away that doing things the easy way would never even occur to me. Possibly this is why I run Linux: there just isn't enough challenge when you run a different operating system. On Windows someone has always written a program for your new weather station, and a Mac user wouldn't be seen dead with it because it's black and beige and comes in a bright yellow box! So now I had to find some code to write. I looked around and very rapidly discovered that some software called vproweather was available, which would happily talk to my weather station and download the data from it, write web pages, stuff it into a MySQL database and so forth. All, obviously, far too easy, so I thought aha! I could convert that to PostgreSQL, and then I would be happy and relax with the thought of a job well done. So I downloaded the code in question an impressive several hundred kb of C code, cranked open a text editor and started to crawl through it and see where I could add the magic pixie dust to make it work with PostgreSQL. But it was not to be. My eyes glazed over or scales fell from them or something, and I realised that this particular edifice was beyond my help. Back to square one. I downloaded the Vantage Serial Protocol docs from the Davis Instruments website did some quick googling and decided I should write a module to talk this protocol. And I should write it in Perl (it was a Thursday, and Perl always seems more sensible on a Thursday, and not because of Douglas Adams, either). I beavered away into the night. Rain threatened, so I raced outside and installed the new weather station on the roof in the hopes that it's magnificent rain collector would collect. I raced back inside and was able to count the first (and so far, only) tip of the bucket. And so I now release upon the world Davis::VantagePro my first perl module. Well, the first one I care to share with the world, anyway. I have stressed it with very little testing, lumbered it with no planning or design whatsoever and so I feel it only fair that I should cast it upon the world with very little thought for it's survival or existential goals.

¹ I seem to recall one night we came up with some fantastic names for Micah & Biella's Washington Square apartment, but I couldn't remember any of the good ones and had to slap a new one on there. I should also mention my stay at the Acetarium in Boston, which was a fabulous few days, but it would pad this blog post needlessly, and I've already done that.

Dato pointed out on my post yesterday that I had omitted to link to the Ikea catalogue. And then it hit me - I am completely failing to monetize this blog! (Sadly, Ikea aren't in a position to give me any kickbacks right now.) Since my money would be spent on innovative Swedish design in any case, I present a new microdonations system: Flattr-pack. I'll add a "Flattr-pack this!" button to everything I write, and then you can send me furniture with one easy click. Unlike other systems, this has the advantage that no one will be taking a 10% cut of your donations. Awesome! Or maybe not. For those who don't know what I'm on about, Flattr is a website that lets you donate small amounts of money to other websites. It has been proposed to use this site to support free and open source software (FOSS). Now a quick modern anthropology lesson: in a 1998 essay titled "Homesteading the Noosphere", Eric Raymond conjectured that FOSS society is a gift economy; your reputation is proportional to how much you give away. At first sight, microdonations drop neatly into this system; after all, the users are giving money away, right? And yet somehow, I don't think those users are gaining much in terms of reputation. Not in the same way as if they reported bugs, say; joined a localization team; or even just turned up to conferences and volunteered to sit on the front desk. Both types of activity could be described as "donations" - but in one case, the donation benefits the whole community around the project, and in the other it goes to just a few top developers. It's a plain old exchange economy in disguise. I do hope that those users are not dissuaded from making the more generous donations just because it's more convenient to whip out a credit card. That would not be in their long-term interests, or those of the community as a whole. I fear this scheme could also incentivize some oddly inefficient behaviour; writing blog entries purely for their donation potential, say, or even content-free search-engine optimization posts. Speaking entirely personally, I do not plan to join in.

So, I m (almost) back from the first edition of MiniDebConf Paris, which was a success thanks to the great organizing skills in panic mode of Carl Chenet and Mehdi Dogguy. I think that everybody is already looking forward to the next edition. I met lots of people, and it was great to be able to finally put faces on names from the french free software community. I gave two talk there, the first one on Debian and Ubuntu (slides), the second one on Debian Quality Assurance (slides), which both went well (I think). I also hacked a bit:

• I added tags and claimed by to UDD Bugs Search.
• I worked on my piuparts replacement (which really needs a sexy name ; I m open to suggestions), processing the results, making some improvements to the script, and filing 16 RC bugs.

If you want to help me, here are some easy tasks that need takers (it s unlikely that I ll be able to tackle them anytime soon):

• One missing thing in UDD Bugs Search is information about the deferred/delayed queue. Unfortunately, the ftp-masters status information is not available in a machine-parseable format.
  • Improve dak code to also export the data in a machine-parseable format (JSON, YAML). I was told the changes are to be done in dak/show_deferred.py.
  • Write the corresponding UDD importer (actually, that s a 30 mins job for me, so I could easily find time to do it if the data was available).
  Update: done!
• Another missing thing is comments (as on bts.turzimmer.net). I don t really have good ideas about how to implement them, so if you want to tackle that with your own idea, go ahead. (It s probably easy to setup a copy of bugs.cgi on alioth if you are not a DD). The CGI is in Ruby.
• Help me process the logs of my piuparts replacement, and file the bugs. I don t have any good scripts to automate bug filings yet. You need a good understanding of packages dependencies and maintainers scripts, but it s a good way to learn, too. (I would need to regenerate the full results first, so talk to me if you are interested)

One of the other things I d like to do is discuss ways to improve the synchronization of UDD (currently, it s synchronized at arbitrary times, while we could sync Sources+Packages just after dinstall, for example).

I disabled my Facebook account about a month ago. See the blog post when I started my Facebook hiatus for the reasons. Now, almost one month into my hiatus, I must say that it has been surprisingly easy. While I do think I probably missed some interesting things my friends are doing (or maybe even did not get invited to some parties; a lot of things are Facebook-only nowadays, unfortunately) I do have the impression that I have much more spare time and that I'm more productive. To my most important friends (in particular my girlfriend of course) I've been keeping my contact out of Facebook anyway, so I didn't lose anything there. So essentially I'm continuing my Facebook hiatus for an indefinite amount of time. I just wonder how to inform my Facebook friends that are expecting my back anytime soon ... and I do hope they'll at some point realize that some of their friends are not on Facebook by choice, but still deserve to be invited to parties and such.

A couple of month ago, my step-father-in-law encountered quite some problems with the Windows installation on his Notebook and therefore showed a great interest in dem Linux da. So we installed him a Debian in a dual-boot setting. It was interesting to see how a basic school teacher (who is technical interested, but has no deeper technical knowledge of computers) worked with Linux, what problems he found, and how he solved them. But a big obstacle for him to work more or less entirely with Linux has always been power management problems with his notebook. To be more precise: While it was always possible to send his notebook into suspend or hibernate, it was also always impossible to wake the notebook up again. It seems that the (non-free but needed) NVidia driver was a part of the problem. Last weekend we again tried to solve the problem by installing the latest backported kernel and updating the NVidia driver, but failed again. So we decided, that with the squeeze being frozen for quite some time, it would be safe to upgrade his Notebook to that system. And believe it or not: It works! We can suspend the notebook without any problems and it will wake up again! And to his (and our) special delight waking the notebook up is a lot faster, than it used to be with his Windows (Vista?) installation. Not to mention that for some reason a suspended Linux-System seems to consume less power (he lend some kind of energy consumption measuring device from his power company to track energy saving potential, and while playing around, we also measured his notebook), than the suspended Windows on the very same system! I don't know why, but finally the installation of dem Linux da was a complete success :) So kudos to those who worked on that area :)

I use ratpoison as window manager on my ASUS EeePC netbook nemo for more than two years now. But although I m very happy with ratpoison in the EeePC, there are two feature wishes which have been refused by upstream: One is more flexibel window name matching for the unmanage command. The other one is focus follows mouse between ratpoison frames. Well, I always guessed that it was possible, but it took until now to find outhow to implement focus follows mouse for ratpoison. There s an ancient but still useful tool called Not a Window Manager (nawm) which is a small awk-like interpreter offering mostly window handling functions. The following .nawmrc implements focus follows mouse in nawm:

window newwin;  # stores window to raise
window lastwin; # stores previous window to prevent race conditions
leave  
    lastwin = currentwindow;
 
enter  
    newwin = pointerwindow();
    if (name(newwin) != "" && newwin != lastwin)  
        raise newwin;
        sync;
     
 

The leave hook is necessary to prevent flapping between two windows if switched between them via ratpoison s commands. I also had to add the following hook to my .ratpoisonrc to work around some cases where ratpoison s own window switching didn t work anymore. Only happened with more than one frame with one frame banishing the mouse cursor was annoying, so I filtered that case:

addhook switchwin exec if [  ratpoison -c fdump fgrep -o frame wc -l  -gt 1 ]; then ratpoison -c banish; fi

Unfortunately nawm has been removed from Debian Sid about a year ago due to being buggy and orphaned. There was not upstream development for seven years or so either. So for the moment you can get nawm either from Debian Lenny or from snapshot.debian.org. But I had to fix a segfault in nawm when calling name() on a window without name to be able to use it at all, so you will probably have to rebuild it anyway with the following patch:

diff -u nawm-0.0.20030130/builtins.c nawm-0.0.20030130-patched/builtins.c
--- nawm-0.0.20030130/builtins.c        2010-10-25 06:00:02.000000000 +0200
+++ nawm-0.0.20030130-patched/builtins.c        2010-10-25 04:15:25.000000000 +0200
@@ -546,8 +546,12 @@
     *name = gcstrdup("");
   else
      
-      *name = gcstrdup((char *)nm);
-      XFree(nm);
+      if ((char *)nm)  
+        *name = gcstrdup((char *)nm);
+        XFree(nm);
+        else  
+        *name = gcstrdup("");
+       
      
  

And yes, I m thinking about adopting and reintroducing the nawm package into Debian Sid. But I d prefer if anyone could give me a hint how to do this with more current and still maintained tools (or a patch against ratpoison :-). I looked into suckless-tools, but I haven t found anything in there which provides hooks on X events. And the Perl module Tk seems to be able to set X event hooks, but only within the application being written itself.

I didn t quite believe what I was seeing until I searched and found several other people noticing the same behaviour. For background, Facebook recently introduced the concept of groups not in the sense we ve been used to, but more like lists. Groups are supposed to be to lists what databases are to bits of paper. You can add friends to groups to organise them, send them group emails, run a collective mailing list, and so on. Except that in practice, this is another really good way of exploiting lazy users. See, there are some things to know about groups:

• you don t have to opt in to one; friends can add you and that s it no confirmation necessary
• it seems that even if the group is closed, members can add other members without any controls
• if you re added and you switched off email notifications in general, you don t even know it
• the group gets an email address, which sprays inbound mail to every member until they get fed up and switch it off

The second point may be wrong it s very unclear exactly what permission is afforded to a group member and when or where information about the group membership is published. Since my day job is in private education, this immediately makes me think of two terrifying scenarios:

1. A student inadvertently gets added to a large group and nobody notices because there is so much other traffic. Whatever my other privacy settings, anything I or anyone else posted to the group is now visible to him this is the same as the previous group arrangement. The difference is that he can now go on and add anyone else Mark Zuckerberg himself even without any kind of checks by the group administrator. A membership system like this quickly spirals out of control.
2. Somebody with a grudge maybe I took too long fixing their PC adds me to a group with, shall we say, inappropriate or unsavoury content while I m away on holiday and tips off the child protection officer. Better yet, he first sends an email to all staff expressing horror and asking them to verify this in case it s his computer lying. Now there are multiple witnesses to the fact that I was a member of this group, and I return from the sea side to find a P45 on the door mat.

Unlike free software, I can t fix this. Fortunately, I have: enabled every email notification under the sun; few and trustworthy friends; according to my profile, no interests or contact details whatsoever; and no care for groups. I m happy with my lists, thanks all the same.

Email. We get a lot of it. We filter out the SPAM. Then if we're well-organized we file it away into folders as it arrives. (To be fair some people use priority settings such that all mail stays in their INBOX until they're "done" with it. I've never had the patience for that kind of behaviour.) One problem which I often encounter is wanting to have email be delivered, archived, and stored, but I don't want to read it. Yet when I see a folder in my mail client which has unread mail in it I cannot unsee. In my case I deliver mail to folders as it arrives via either Exim's filter language, or procmail. Procmail blows goats on the whole, but it is common and available everywhere - I just don't trust my own DSL enough to rely upon it (which is a dangerous sign). So, how do you deliver a new mail to a Maildir folder, and mark it read at the same time? Well you can be na ve and do what I did which is to invoke formail to add "Status: ro" to the header. Unfortunately that's insufficient to mark a mail as read when viewed in mutt. When an email is stored in a Maildir folder its status is encoded in part of its filename - which is why you'll have files like:

new/1288039894.28406_3.steve.org.uk
cur/1283711971.11157_3.skx.xen-hosting.net:2,S

The latter file has been Seen. So to mark a message as not-new you need to do two things:

• Save it to ./cur/ not ./new/.
• Append the appropriate flags to the filename (generally :2,S).

I've seen some horrific shell + procmail code to do the job, but the simpler version is:

:0
*^(To: From:).*root@
*^X-added-header:.*debian-administration.org
  ~/bin/read-to-maildir .machines.debian-administration.org/

Similarly you can use Exim's filter language to do the same job:

# Exim filter
if $h_to: contains "hostmaster@" then
    pipe "/home/skx/bin/read-to-maildir /home/steve/Maildir/.hostmaster/"
finish

Cute. Obvious too? Maybe not to me. ObSubject: Why did you murder someone, Raymond? - In Bruges