tldr: counting without cumulative timing errors Sometimes I want just a small counter, incrementing an integer each second running somewhere in a terminal. Maybe it is because my wristwatch is in the bathroom or because I want to do more rewarding things than counting seconds manually. Maybe I want not only to know how long something takes but also for how long it already ran in the middle of its execution? There are many reason why I would want some script that does nothing else than simply counting upward or downward with some specific frequency. Some bonuses:

• the period should be possible to give as a floating point number and especially periods of a fraction of a second would be nice
• it should be able to execute an arbitrary program after each period
• it should not matter how long the execution of this program takes for the overall counting

Now this can not be hard, right? One would probably write this line and be done with it:

while sleep 1; do echo $i; i=$((i+1)); done

or to count for a certain number of steps:

for i in  seq 1 100 ; do echo $i; sleep 1; done

This would roughly do the job but in each iteration some small offset would be added and though small, this offset would quickly accumulate. Sure that cumulative error is tiny but given that this task seems to be so damn trivial I couldn't bear anymore with running any of the above but started looking into a solution. Sure I could just quickly hack a small C script that would check gettimeofday(2) at each iteration and would adjust the time to usleep(3) accordinly but there HAD to be people before me with the same problem who already came up with a solution. And there was! The solution is the sleepenh(1) program which, when given the timestamp of its last invocation and the sleep time in floating point seconds, will sleep for just the right amount to keep the overall frequency stable. The author suggests, that sleepenh is to be used in shell scripts that need to repeat an action in a regular time interval and that is just what I did. The result is trivial and simple but does just what I want:

• the interval will stay the same on average and the counter will not "fall behind"
• count upward or downward
• specify interval length as a floating point number of seconds including fractions of one second
• begin to count at given integer and count for a specific number of times or until infinity
• execute a program at every step, optionally by forking it from the script for programs possibly running longer than the given interval

You can check it out and read how to use and what to do with it on github: https://github.com/josch/periodic Now lets compare the periodic script with the second example from above:

$ time sh -c 'for i in  seq 1 1000 ; do echo $i; sleep 1; done'
0.08s user 0.12s system 0% cpu 16:41.55 total

So after only 1000 iterations, the counter is already off by 1.55 seconds. This means that instead of having run with a frequency of 1.0 Hz, the actual frequency was 1.00155 Hz. Is it too much to not want this 0.155% of error?

$ time ./periodic -c 1000
0.32s user 0.00s system 0% cpu 16:40.00 total

1000 iterations took exactly 1000 seconds. Cool.

Dear Lazyweb,

is there a simple way to block some users who login with SSH to read /proc/<pid>/cmdline of processes they don't own? Or better yet: don't see these pids at all?

I know that there are PID namespaces, but they seem to require a special PID 1. Seems hard to get for a simple SSH login. (I wouldn't mind changing a user's shell. But brittle shell startup scripts wouldn't cut it.) systemd-nspawn wants to boot a full Linux distribution in a container and even then I'd be unsure how to wire it up so that it cannot be skipped. I wouldn't mind a read-only bind mount of the outermost Linux installation into a chroot environment, as long as the parent SSH process can get the user jailed into it securely. (No need for someone to be root in the chroot.)

I know that there are RBAC frameworks, but they're cumbersome to use. I don't need file labelling or path-based access control, as I do trust the Linux file permissions for this. I think SMACK wouldn't help here, AppArmor isn't really useable in Debian testing and TOMOYO is a tad crazy to use with its domain transitions through process invocations.

I bet that grsecurity would have something for me up its sleeve. But it's not in a Debian kernel. Even though I know how to compile my own kernel I'd only do that if everything else fails.

Thanks in advance for your help.

UPDATE: That was quick, thanks to everyone who participated! Vasiliy Kulikov came up with a kernel patch to my problem (a hidepid mount option for procfs) that landed in 3.3. I tested it with the kernel in experimental and it works just fine and as expected. With hidepid set to 1, it will still leak the process count and their euids and egids. With hidepid set to 2, you only see your own processes, unless you're root. For ps there's no visible distinction between the two. So to test it you can just invoke this as root on a host running 3.3+:

mount -o remount,hidepid=1 /proc

There's even a backport request in the Debian BTS to get the feature into the wheezy kernel (3.2).

A new release 0.2.4 of RProtoBuf is now on CRAN. RProtoBuf provides GNU R bindings for the Google Protobuf data encoding library used and released by Google. This release once again contains a number of patches kindly contributed by Murray Stokely, as well as an added header file needed to build with the g++ 4.7 version which has become the build standard on CRAN. The NEWS file entry follows below:

0.2.4   2012-05-15
    o   Applied several patches kindly supplied by Murray Stokely to
         - properly work with repeated strings 
         - correct C++ function naming in a few instances
         - add an example of ascii export/import of messages
    o   Suppport g++-4.7 and stricter #include file checking by adding unistd
    o   Made small improvements to the startup code

CRANberries also provides a diff to the previous release 0.2.3. More information is at the RProtoBuf page which has a draft package vignette, a 'quick' overview vignette and a unit test summary vignette. Questions, comments etc should go to the rprotobuf mailing list off the RProtoBuf page at R-Forge. Updated to show NEWS rather than ChangeLog

Hey, thanks, Peter for the hint! Never heard of that option until you blogged about it. So, now I'm also ready to "tar taf", "tar xaf", "tar caf"..:-). Harder for me than you because I was used to "tar tfz" or "tar tfj"..:-) And I suspect that "tar taf" is prone to typos...we'll see.

I ve been noticing a number of odd things happening surrounding my blog lately, and I thought it s about time to figure out what s going on and how to stop it. The first problem is that people are illegally copying my posts, probably using RSS scraping, and putting them up on their own ad-infested sites. It is trivial to find them using Google for any somewhat unique word or phrase in one of my posts. Lately one of them, linux-support.com, actually sends me pingbacks announcing the fact that they ve scraped me! Most of these sites seem to be nothing but content farms for selling ad impressions, and almost none of them have any identifiable names for the owners. (There is an exception: I have specifically set up sites like Planet Debian and Goodreads to copy my blog posts.) I m obviously an advocate of open content, but I do not feel it right that others should be profiting by putting photos and stories about Free Software, or photos of my family, on their ad farms. While I release a great deal of content under GPL or Creative Commons licenses, I have never done so with my blog an intentional decision. What should I do about this? Is it worth fighting a battle over, or is it about as useless as trying to block every spam follower on my twitter account? So that s the first weird thing. The second weird thing just started within the last few weeks. I have been getting a surprising amount (a few a week) of email addressed to me. It does not bear the appearance of being 100% automated spam, though it is possible that it is. It s taken a few forms:

• Someone wanting to buy an ad on my blog
• Someone wanting to send me a story hyping their product (and intending me to pretend that I wrote the story)
• Someone wanting me to write a story about their website and link to it

The profit motive in all of these is high, and in at least the second and third, so is the sleaze factor. I ve gotten two emails lately of this form:

Hi John, I am curious if you are the administrator for this site: changelog.complete.org/archives/174-house-outlaws-fast-forwarding-senate-pres-next I am a researcher / writer involved with a new project whose mission it is to provide accurate and useful information for those interested in the practice of law, whether as a lawyer or paralegal. I recently produced an article detailing the complex relationship between law and technology and the legal implications on personal privacy and free speech. I would love to share this resource with those who might find it useful and am curious of you are the correct person to contact about such a request? Thank you! All my best,

The details vary the URLs appear to be random (the one cited above was little more than a link to an article), the topics the website claims to discuss range from law to schizophrenia (that one actually came with a link to the site, which again seemed to be a content farm). I am slightly tempted to reply to one of these and ask where the heck people are getting my name. It seems as if somebody has put me into a mailing list they sell containing sleazebag bloggers. Frankly, I am puzzled at this attention. I guess I haven t checked, but I can t imagine that my blog has anything even remotely resembling a high PageRank or anything else. It s not high-traffic, not Slashdot, etc. Either people are desperate, naive, failing to be selective, or maybe working some scam on me that I don t know yet. In any case, I m interested if others have seen this, or any advice you might have.

This year, the annual Debian conference will be held in Managua, Nicaragua. And I'll be lucky enough to spend two weeks visiting the country after Debconf, along with Elisabeth. Yes, I'll arrive in Nicarague on July 2nd, spend nearly the entire Debcamp, then Debconf, then we'll spend 16 days around the western part of Nicaragua, trying to discover the magic of this country. So, this post is about sharing our plans with my readers. Of course, I do not know the country so we may have made mistakes and bad choices. We'll see. Immediately after Debconf, Elisabeth will join in Managua. She'll be landing on July 15th. We'll then spend a night in an hotel near the airport and immediately leave the day after for Matagalpa, in North Nicaragua. We rented a car for the entire trip indeed, and will be on our own on wild Nicaragua roads..:-) We'll spend two nights in Matagalpa. We plan to visit some coffee or cigar plants, probably have a trip to Lake Apanas and Jinotega. Then, we'll have a short road trip to Esteli where we spend again two nights. We'll be visiting a coffee growing place (beneficio seco de caf ). A full day visit is planned at Miraflor natural reserve to enjoy te beauties of hundreds orchids and some local natural marvels. The next move will be to Leon, where we'll spend 4 nights, visiting a cigar factory (tabacaleras de puros?) on the way, as well as San Jacinto, a place with hydrothermal sources and "Hervideros" (geysers). Four nights in Leon leaves plenty of time for several activities *and* enjoying the colonial city. We'll have a full day at Juan Venado Island reserve with boat trip from Las Penitas (on a fisherman's boat from what the travel agency mentioned), then another full day climbing on the Cerro Negro volcano. Indeed, I was originally considering climbing the Momotombo, but our travel agency warned about the high difficulty. I would have loved that myself but maybe not the two of us...and this is a trip for both of us! So, we played the safe option..:-) After these 4 nights in Leon, we'll move to Granada for 3 nights, through Leon Viejo (the former site of Leon). From Granada, one day will there be used for a visit in the Masaya National Park and see the beauties of Masaya volcano (this is indeed something that could be done for Debconf day trip, IMHO, as it doesn't seem that far from Managua). Another day will be spent to Las Isletas on lake Nicaragua and others visiting the colonial city of Granada. Or, of course, whatever things we don't even known about now..:-) Then we'll move to what I personnally consider the peak of the trip: 3 nights on Ometepe island on lake Nicaragua. Just check Wikipedia to see why Ometepe is, in my opinion, THE place to go in Nicaragua. Here, I'll have my volcano..:-). Indeed, Elizabeth "authorized" me to book a local guide and then climb Concepcion Volcan, if the weather allows for it. 1600m height, that doesn' seem to be a big issue....except when starting from a little bit above sea level and are climbing a volcano that looks like s postcard volcano : nearly a perfect cone shape. So, let's cross fingers for having good weather that day. I promise myself I'll record the GPS track of that one and, even if I'll probably be walking most of the climbing (except if I have a very trained guide...), I'll add it to my run tracks! We might also be going to climb Ometepe's other volcano (Maderas) the day after so that Elizabeth also enjoys these beauties. There also seems to be great places around Maderas such as San Ramon Cascade, Finca el Porvenir, etc. Then, at the end of all this, it will be time to come back to Managua in the final day and fly back to Paris in the early morning of July 31st. All over, I'll be in Nicaragua from July 2nd until July 31st! Full month away, yay! Hurrah for the crazy number of holidays those lazy French people have..:-) During this trip, we might find it interesting some local geeks (not too many as Elizabeth is not that deeply interested in beersigning!) and share a few nice things in local places which are only known by locals. In case you're interested, out (very clever) travel agency is named Nicaragua Adventures and they're definitely worth contacting if you want to travel around .ni, particularly if we prefer booking things in advance as we do. They speak Spanish (of course!), English and French. They're very responsive to e-mail as well.

You can get inspired from the most unlikely of places, and this time it was a twitter background image. I came across the twitter profile of @Nitish today, a fellow GSoC student from India. One thing that held my attention, apart from the fact that he tweets crazy, was the background picture in his profile. Yes I had not seen something like that before and I absolutely loved the concept. The image was large grid and each tile carried the profile picture of one of his twitter followers. It was beautiful. The background image was generated by twilk, a very popular application that I had never heard of. I wanted to try it, but I figured my follower count might be a little too low for the application to work. Twilk works only with twitter and I wanted it for Facebook. Instead of looking for something similar, I decided to write it myself. I had worked with the Python Imaging Library some time back and knew it would not be very difficult task. The first thing I needed was the profile pic thumbnails of my friends. Facebook API supports a call which returns a small 50x50 pixel profile pic of a user, if we send a valid user ID. I wrote a quick script that returned the user ID s of my friends on Facebook as JSON data. I grepped the user ID s from the JSON and wrote a small wget script to download the profile pics of all my friends to a directory. Once the download was in progress, I started my work with the imaging library. I knew the image count beforehand and after some quick math, I fixed the dimensions of the output image that I wanted. Once the dimensions were fixed, the work was fairly easy. I knew before hand how many images will be there in each row and how many rows will be there in total. All I had to do was to randomly pick one of the images from the directory, and arrange it on the output image canvas. Few lines of code later I get the result that I wanted and it is on my twitter profile. Yay! :) I have uploaded the python code in here. If you are running it, make sure you change the values according to your requirements. The image below is a cropped out from the output image to fit this div. Click on it to see the actual output. When I showed this to @Jaseeemabid, he asked me to put this up on Google App Engine and start a service so that even non geeks could use this. I liked the idea but I am slightly busy(lazy) now. I ll do it when I am free or when I see that there is some demand for this! :) Update As few Redditors pointed out, this may not be the best way to do it. This was just a quick hack to get something done. The JSON could be processed in Python itself and files can be downloaded as well. I modified an old PHP script to get the JSON data and since the structure was relatively simple, I grepped the relevant information and fed it to wget as I prefer wget over any other tool for mass downloads. Update 2 Redditor Bio Lazarus improved upon this and made an end to end version that does all of the above in one single python script and the code is available here. And if you like this post, you should follow me on twitter :)

For years, no decades, I've typed tar tzf something, tar xzf something. Except when someone annoying sent an uncompressed tar file and I had to then go and take out the z in the middle. Then came bzip2, and we learned tar tjf, tar xjf. OK, I could live with that. One emerging problem was that the tab completion now worked the wrong way around conceptually, because you had to pick and type the right letter first in order to see the appropriate set of files to unpack offered for completion. Then came lzma, which was (quick, guess?), tar tJf, tar xJf. And then there was lzop, which was too boring to get its own letter, so you had to type out tar -x --lzop -f. But lzma was short-lived, because then came xz, which was also J, because lzma was now too boring as well to get its own letter. Oh, and there is also the old compress, which is Z, and lzip, which I'd never heard of. But stop that. Now there is

 -a, --auto-compress
            use archive suffix to determine the compression program

This handles all the above compression programs, and no compression. So from now on, I always use tar taf and tar xaf. Awesome. The finger movements will be almost the same on QWERTY and AZERTY, and easier than before on QWERTZ. Actually, this option is already four years old in GNU tar. Funny I'd never heard of it until recently.

I recently setup an Alix board from PC Engines. I installed Debian onto a Compact Flash card using grml for the first time. After using parted to create a single partition, I ran:

grml-debootstrap --arch i386 --filesystem ext4 --grub /dev/sdb --hostname yaqeen --mirror http://http.us.debian.org/debian \ 
--nopassword  --release squeeze --target /dev/sdb1

I had to manually mount the partition and add console redirection for grub (and /etc/inittab). And then, when booting, I had to manually edit the grub configuration because it was trying to find the root filesystem on /dev/sdb instead of /dev/sda. I'm sure there is some tweaking I can do via /etc/deboostrap/scripts to fix those needs. Overall, I was very happy with the results. Thanks grml developers!

Sparkleshare is a file sharing utility that keeps folders in sync on multiple computers in a similar fashion to the commercial and proprietary Dropbox. Sparkleshare recently released a Windows client, finally allowing me to start switching my co-workers at the Progressive Technology Project away from Dropbox. Overall, I'm very impressed. In particular, I appreciate the Sparkleshare authors' decision to build on top of existing tools (git for storage and revision control, ssh for transport, and ssh public key infrastructure for authorization and authentication). That means I don't have to learn new tools and protocols to debug and it means Sparkleshare can focus on the file sharing pieces. Despite my overall enthusiasm, I do have some serious concerns. Protecting your credentials A researcher found a startling security flaw in Dropbox - if you can copy a particular file from a user's computer to your own computer, you can impersonate them flawlessly, accessing all their Dropbox files without having to know the user's password. Unfortunately, Sparkleshare suffers from this same vulnerability if you use the default configuration. When you first install Sparkleshare, it creates a password-less ssh private/public key pair and then makes the public part easily accessible to you so you can add it to your server (or gitorious account, etc). Very convenient. But it also means that all an attacker needs to do is copy your private key (and your Sparkleshare configuration file) and they get complete control over your files. This problem is easily avoided. If you are running Linux or Mac OS X and you have your own key loaded in your ssh agent, Sparkleshare will happily use that key. So - simply by using your existing (presumably password-protected key) on your remote Sparkleshare servers, you can mitigate this problem. Sparkleshare will still load your Sparkleshare generated key, but if you don't provide that key with access to anything, no harm is done. Confirming each use of your key However... that leads to a new problem. If you are like me, your ssh agent is configured to ask for a confirmation every time your key is used. And, Sparkleshare regularly polls the remote git repository for changes. At best repeatedly clicking to confirm is tedious. At worst, it prevents you from intelligently rejecting malicious requests, thus defeating the whole purpose of the check. It is possible to launch Sparkleshare via ssh-agent in an environment in which you are not requiring the confirmation when Sparkleshare uses your key, but still requiring it for all other uses. However, given the trade offs, I've decided to add a password to my Sparkleshare provided ssh key rather than using my existing key: ssh-keygen -p -f ~/.config/sparkleshare/sparkleshare.jamie@progressivetech.org.key Now, I am prompted to enter my passphrase when I start Sparkleshare and don't have to confirm every use of the key. And, I continue to confirm each use of my main key. git was designed to store code, not documents Just because something is designed for one purpose doesn't mean it can't be used for another. However, there are a few limitations. Large files are one. git can handle files over 100MB, but may run into memory problems. I had to alter the git windowMemory setting, raising it higher than the size of the largest file. Another problem is disk space. Since git keeps full revision history on every machine, you have to download more data than just the files that are checked out. The more edits you make to a repository, the more disk space beyond what is checked out is needed (and deleting files won't help). Lastly, you can't use file modification times. With git, the file modification time will depend on when you checkout the files. With some fancy hook writing, you could tweak things so that the file modification date is the same as the commit date, but that still won't help you if you add an existing directory to Sparkleshare because all the files will have the same commit time. This "bug" has been reported to git and it has been rejected because mucking with the modification time of files can have bad results when you are using make to compile code. As Linus colorfully put it:

I'm sorry. If you don't see how it's WRONG to set a datestamp back to something that will make a simple "make" miscompile your source tree, 
I don't know what definition of "wrong" you are talking about.
It's WRONG.
It's STUPID.
And it's totally INFEASIBLE to implement.

Well, did I mention that git was designed for source code? No server validation Of all the problems I encountered, this one is by far the most serious. Perusing ~/.config/sparkleshare/debug.log is very informative. On a default installation, after you have added a project, you'll see:

19:32:27 [Fetcher][/home/jamie/SparkleShare/.tmp/bar] Fetching folder: ssh://foo@bar.org/foo/bar
19:32:27 [Fetcher] Disabled host key checking for bar.org

Wah. Once the project is added, whatever key fingerprint is given is stuffed into your ~/.ssh/known_hosts file. Host key checking is only disabled when you initially create the project, so if you connect to the proper server the first time, you are protected from subsequent man-in-the-middle attacks. However... if the initial fingerprint is wrong, your personal ssh configuration is now poisoned. This seems like a very bad idea. I've opened a debian bug to address it.

When I wrote lvmsync late last year, I didn t realise I was being typecast. Before too long, I realised that the logic that I d implemented for lvmsync would also help me with a separate migration project I d been dreading getting the day job off VMware. Back in the early days of virtualisation, management made the decision to run VMware, for all the usual reasons ( commercially supported! , industry standard! , and so on). Unsurprisingly (to me, anyway) it didn t take too long for management to realise that it wasn t the best choice for us. When you ve got umpty-billion dollars to spend on hardware, software, and support, VMware might be the right option (although Amazon doesn t seem to think so). Anchor s company culture, on the other hand, is build around smart staff, simple systems over dumb staff, smart vendors , because no vendor is ever going to care about our customers as much as we do. So VMware was never going to work for us. Unfortunately, as happens all too often, once VMware was in place, there was very little motivation to get rid of it and move those customers onto the chosen replacement (that we were deploying all new customers on). I happen to think this is a terrible attitude in general one that makes life so much harder in the long term. I believe strongly in retrofitting old systems to keep them up-to-date with the current state of the art, and keeping technical debt under control. But, I wasn t running the show back when we stopped putting new customers on VMware, so the few VMware servers we had stayed around far longer than they should have. Recently, though, bad things started to happen. The VMware servers were starting to fall apart. The Windows machine we had to keep around to use the VMware management console started crapping out, and when the choice was between doing unspeakable things to Windows, and just ditching VMware well, it wasn t much of a choice. The only remaining question was how to do the migration off VMware with the least amount of downtime to our customers. I was really quite surprised that nobody out in Internet land appeared to have come up with a simple, robust tool to do this. Sure, some vendors had all-singing, all-dancing toolkits that cost ridiculous amounts of money, required you to install their agent on the machine involved, and promised the earth, but it all smelt of snakeoil and bullshit. In true hacker style, then, I decided to write something myself. The model I came up with mirrored lvmsync s quite closely because that one worked, and it turned out to be surprisingly easy to implement once I managed to reverse-engineer the file format (VMware has a PDF spec of a bunch of it s file formats, but whoever wrote it was enough of an evil genius to make it utterly incomprehensible to anyone who doesn t already know the file format, whilst making perfect sense to anyone who already does). The result: vmdksync. It is nothing but 80-odd lines of ruby whose sole purpose is to take a delta.vmdk file and write the changes that are stored in that file to a file or block device that is a copy of the flat.vmdk file that you can copy while the VM is still running (after you ve made a snapshot, of course). It helped me provide a painless migration path away from VMware, and I d be really pleased if it helped some other people do the same. Share and enjoy!

I ve send a mail today with a summary of some of my experiences in Managua and tiny bits of Nicaragua late April / early May 2012. If you are considering going to DebConf12 (which you obviously should do as you are reading this!) go and read this mail, as it includes a thematically sorted list of impressions and advice written by Gunnar, Norman, Leo, Felix and myself, which should give you some better idea about DebConf12 in Managua! While I spent 14 days in Nicaragua in total, for the last three days I was joined by Gunnar Wolf, to make sure my impressions about the local team, the status of the preparations and everything were correct. Our visit also seems to have been very motivating to local team members, whom I ve seen really enthusiastic to welcome a huge Debian crowd for the first DebConf in Central America in just a few weeks! At the last DebConf12 IRC meeting I summarized it like this: in very short: my two weeks were great, I had a great vacation, met many members of the localteam, which is way bigger then it seems on irc, saw and liked UCA (Universidad Centroamericana, the DebConf12 venue), had zillions of reunions (meetings, see schedule wiki page) and met many nice people and a very hot & interesting country+capital with great countryside. The deadline for sponsored accomodation ends in three days - so if you haven t registered yet, hurry up, DebCamp starts in 49 days! :-) (After that registration is still possible, but you will need to pay for your costs yourself.) We re looking forward to see you there and have a great DebConf together! Hopefully we sweat together while Wheezy is frozen :-D

Note: this is a rant. For year, I've browsed the web with Firefox set to Allow pages to choose their own fonts: no . It worked everywhere very well, and I had a consistent style across pages, and I wasn't forced to see the (IMHO) very ugly Microsoft-fonts look-alikes. That all changed until GitHub introduced their Octicons font, and represent icons with characters, instead of actual icons. Now I either am forced to:

• not be able to use GitHub's web interface, or
• allow all sites to use random font of the day, or
• start playing with custom style-sheets and overrides and whatnot

Grr At least they added text labels too, so at least I get a small box with F044 and label Admin .

Do you wish, like I do, you could edit collaboratively in Vim? This feature is number 10 on the Vim voting page, so it seems I m not alone. How about Pentadactyl coupled with any of the existing web-based collaborative editors, such as Etherpad? OK, so it s not quite Vim, and there are some rough edges to this particular pairing, but I m finding it s good enough for my needs. It even gives me a Vim-like editing experience while other participants use the default Etherpad editor. Yes, I know about whiteboard.debian.net, but for the past three years I have been using a single instance of Etherpad with my family to maintain a shopping list to which we all make contributions. First of all, that s not a Debian activity, so to make the switch, I d need to make a personal clone of the service for our personal use. But more importantly, we find Etherpad features such as colours for different participants and the timeline are just too useful to give up on. On the other hand, the less the web editor interferes with your web browser s default textarea behaviour, the easier time Pentadactyl is going to have. Indeed, I asked on #pentadactyl @ irc.oftc.net about some problems I was having and I was told flat out that Pentadactyl does not work with graphical web editors. So, you may wish to use another web-based collaborative editor for this reason. That being said, I did learn a few things about helping Pentadactyl get along better with Etherpad, so if you would like to try it yourself, read on. The key to getting started was to enter text edit mode within the textarea with <C-t>. For the most part, this behaves like Vim normal mode . I am still learning, but many basic motion and editing keys behave just as they would in Vim. Fantastic! However, the moment I tried to :undo I hit my first problem. Using the latest release version of Pentadactyl (1.0rc1 at time of writing), pressing "u" to :undo produced no visible result. I tried the latest daily build as well, and only saw a marginally more helpful "Node not found" error message displayed in the status area. But it turns out you can use passthrough mode to use the textarea s own undo. Just :tmap u <C-v><C-z> and we re back in business again. I m still experimenting with this setup, so the jury s still out on whether I ll stick with it, or whether the remaining incompatibilities between Pentadactyl and Etherpad will drive me nuts. But it looks promising. Clearly, judicious use of :autocmd to always start in text edit mode and bind that undo key whenever I enter the site will help make the experience even better. If you try it out yourself, I d love to hear how things went for you. Or if you have found an even better solution that works for you, do share.

Today, it must have been exactly 10 years that I started using Debian. The story of how I came to Debian shows some of its strengths, so I ll use this occasion to share it. I spent the first half of 2002 as an high-school exchange student in Wenatchee, USA. I was already a user of Linux at that time: I made my first contact roughly in 1996 and did my first installation at home two years later, but all that time I was dual-booting and my main system was a well-arranged Windows 98. The machine was a regular tower PC, but nevertheless I put the computer into my trunk when I flew to the US. It took away most of the space, and I had to put some of my cloths inside the case. So I was there, happily using my Windows and my manually set up Linux From Scratch until one day the inevitable happened; inevitable at least until you start doing backups: On April 30th, my hard drive crashed, and took the two systems together with 4 years of personal data with it. Two weeks later I had a new hard drive and was pondering my options. I did plan to install Windows again; at that time Windows XP was just released. But I wanted a German version of Windows, which would be hard to get there. Also, I did not want to use Linux from Scratch any more, and wanted to make a well-founded choice of a distribution. On the other hand, I really wanted to get my machine up and running quickly, to be able to read my mail more comfortably. I had heard that Debian had good support for network installations (downloading a full 700MB CD was something to avoid at that time), so I grabbed some netinst images, burned a CD, and quickly installed Debian. I was planning to use the system for about two weeks. I did not pay any particular attention to the setup. Heck, I even picked from my Simpsons sidekick machine naming scheme one that I would not miss being used up ( barney ). Nevertheless, I was using this installation for many years (and many upgrades), until I eventually switched to using laptops. In fact, that very installation is still on the machine somewhere and works. I did install Windows XP a few weeks later as well, but hardly used it. So May 12th of 2002 was when I turned into a full-time Linux and Debian user. I soon became interested in Debian the project and started to contribute. But that is another story for another ten year anniversary blog post, most likely on October 21, 2013...

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Recently an ex-colleague of mine changed jobs and suggested that I write something about the pros and cons of working from home. I've thought about this subject, off and on, for a few years and frustratingly I think most of the pros and the cons are the same:

• When you work from home you're working from home.

I live in a two-bedroom flat in Edinburgh. (Having just spent thousands on a new bathroom I don't expect I'll be moving any time soon. A rough budget of 40-50,000 would let me convert my attic into two/three rooms. So there is growth potential!) In my flat I have made one of the bedrooms an office. The office contains:

• A huge desk with two PCs, and two telephones on it.
• Several book-cases.
• A wall-mounted fan.
• Very little else.

One PC is for work. One PC is for me. One phone is for work. One phone is my own. Every working day I switch on the work router, the work phone, the work PC around 09:30. I then work, taking a lunch-break between either 12:00-13:00 or 13:00-14:00, until 18:00 at which point I switch off the work toys. I ignore my personal PC during the working day with the exception that it is the source of my music. I can reach across and hit the appropriate multi-media keys to select Play/Pause/Next Track/Previous Track/Volume Up/Volume Down. (When thenever the work-phone rings the first ring is ignored as I scramble to hit "Mute" or "Pause"..!) So what are some of the advantages/drawbacks? Well I'm at home. So the environment is one that I've made myself, and enjoy. The music is mine. The colour-scheme is mine. The pictures on the walls are mine. I have a Steve-loving chair. There is no soulless air-conditioning, no horrible cubicles, and no noisy people talking. The downside? No people talking. If I didn't leave my house at lunchtime I'd speak to zero people face to face in an average working day. That took a while for me to notice, but it is not nice. Since I work from home "the commute" takes seconds. I tend to get out of bed and wander straight to the desk. I'll work non-stop, then get dressed around lunchtime so that I can go out for lunch. Hail, Rain, Snow, or Sunshine I leave the house for lunch every single day (unless waiting for an atypical delivery). Because if I didn't I'd have no human contact. In the afternoon if it is a nice day I'll get undressed again, because I can, so why the hell not? Providing you're focussed working from home has several advantages that I can think of - I've no qualms about setting the washing machine going before I start work knowing that I can "spare" five minutes to empty it later in the day. Similarly I've no concern about ordering (even large) items, because I know what time the postman comes, and I know I'm never going to be out and miss a delivery. When I first started working from home I had a laptop instead of a PC and there were mornings when I worked, lazily, from my bed, or from my sofa whilst watching TV. That didn't last for long because I just didn't do a good job. I think I got away with it in the sense that I don't think people noticed, but I expect if it had lasted for longer it would have been quickly apparent. I stopped because the line was blurring between "home life" and "work life". Having a dedicated working area is essential in keeping me focussed. I don't do "home things" when I'm in "work time" - with very rare exceptions. Yes I wander around and pace if I'm thinking, yes I make more tea and coffee than I would in a real office, and yes I might open windows, phone a friend, read my gas meter, washup dishes, or similar as I'm "making coffee". But on the whole it only works if I work when I'm working. I could save money by using my work-internet instead of paying for personal-internet, but keeping the two links separate is another way of being focussed. I don't do "dodgy" things on the internet, on the whole (haha), but if I do I'd want to be damn sure that that was via my link and not the work-link - and having two PCs and two network links I know that is the case. There have been times when the work link has broken and I've used my personal link + openvpn to continue working, or at the very least re-join our internal chatroom and say "Internet down, brb". As a system administrator there are times when I have to do things either early in the morning, late at night, or even during a weekend. I guess a final advantage is that this is not a struggle - providing I don't schedule such operations at times when I'm in the pub, meeting friends, or taking pictures of cute strangers, it isn't a struggle to say "I'll do this after 8pm tonight", or set the alarm early. No long walk to an office, and if I've already got food cooking for my tea I can eat it nearby whilst still configuring things and testing sites/services/machines. So pros: I'm in my own environment, I don't worry about receiving parcels, meter-readings, and have wonderfully pleasant music all day. Ancillory bonuses are really side-effects of being in my environment: I have my good coffee, my nice cups, I can eat food I enjoy. etc, etc. Cons: You must be dedicated. You must be focussed lest you give in to temptation and cease working for minutes/hours at a time. You lose part of your home space - I can't turn this room into a childrens bedroom, for example. Nothing earth-shattering. I've done this for five years now, and although I was a little skeptical initially I thought "Why not?" It has worked out well and I think if I ever did need to leave my current position I'd have no hesitation about working from home in the future. Finally it has to be said that when I've had partners in my life they've traditionally been the type to wake up later than me. I get significant brownie points for being able to wake them up around 10/11AM with a cup of hot coffee & breakfast in bed every morning. By virtue of having a separate space I can close the door and not be disturbed by them walking around. I'm sure I've forgotten things - but as an initial pass the benefits and disadvantages of working from home are the same: You're in your own house. ObQuote: "Explorers in the further regions of experience." - HellRaiser

As Weblate 1.0 is out, it's time to compare it to existing solutions. As first I've chosen Pootle as this is tool which we have been using for quite some time and I used it as an inspiration for Weblate. First of all, both Weblate and Pootle use same backend for manipulating with translation files - Translate Toolkit. On the way I've learned that I've chosen different way of manipulating with backend files, what seem to lead to much smaller changes (no more reformatting of whole po file as Pootle does). Also Weblate does not suffer from some Pootle issues like not properly handling changes to fuzzy flag, which has bitten us several times at phpMyAdmin. Another shared thing is web framework Django. For me it was obvious choice as I like writing application with it. The biggest difference here is that Weblate relies on Django admin interface for maintenance, while Pootle has everything in it's interface. Pootle has great advantage here for having consistent interface for everything, what was sacrificed in Weblate for less code to maintain (while having powerful Django admin interface). Also sharing same framework allows quite easy migration of user accounts. Now let's functional side of things - this is where I've tried to take all good things I've seen in Pootle, while adding features I've missed there. What makes biggest difference here are project/subproject classification in Weblate, which was originally started as way to handle more project branches, but proved to be useful for translating related projects as well. This allows automatic propagation of changes across project, what is really great for translating more branches of same program or different interfaces to same functionality (eg. GUI application and command line tool). The other big difference (and I would say key feature of Weblate) is Git integration - all changes are commited to Git with correct authorship, it can help in merging po files or automatically pull upstream changes (eg. from GitHub). This all makes integration into (Git based) development process really easy. Other features like consistency checks or dictionary (terminology) are quite similar, though different. There is more consistency checks in Pootle, but the main reason was that I found some of them too annoying. User dictionaries are still pretty basic in Weblate and that's definitely something what should improve in future versions. On configuration side, Pootle is much more flexible. The main reason here is that I've never used most of the options there. So there are no per project settings of checks or privileges. There is also no way to add language from Weblate - usually adding translation is not just matter of adding appropriate po file, but also other steps, which anyway had to be done manually. So Weblate leaves this up to user. On the other side as soon as new language pops up in Git repository, it is shown in the interface. Both projects have quite good documentation - Pootle has most things covered on wiki while Weblate relies on separate documentation. However there are definitely some bits missing on both sides. PS: If you want to want to have more "facts" in comparison, you can check Ohloh :-).

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Another day, s more patches.

• 667343 (qterm)
• 672007 (pokerth)
• 672010 (cryptkeeper)
• 672052 (qastools)
• 672071 (pxe-kexec)
• 672005 (l2tp-ipsec-vpn)
• 672003 (dibbler)

Consider helping out!

I've just released version 0.28 of Obnam, my backup application. The relevant part of NEWS:

• force-lock should now remove all locks.
• Out-of-space errors in the repository now terminate the backup process. Previously, Obnam would continue, ignoring the failure to write. If you make space in the repository and restart Obnam, it will continue from the previous checkpoint.
• The convert5to6 black box test now works even if run by other people than liw.
• "obnam backup" now uses a single SFTP connection to the backup repository, rather than opening a new one after each checkpoint generation. Thanks to weinzwang for reporting the problem.
• "obnam verify" now obeys the --quiet option.
• "obnam backup" no longer counts chunks already in the repository in the uploaded amount of data.