brennen
/
workings-book

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<h1 class=bigtitle>workings</h1>

<article>
<h1><a name=a-technical-notebook href=#a-technical-notebook>#</a> a technical notebook</h1>
<p>I&rsquo;ve been working on <a href="https://p1k3.com/userland-book/">a short book</a> on the basics of the commandline.  This one is something else altogether.  It&rsquo;s a long-form technicallogbook or journal, capturing the outlines of problems and their solutions as Iencounter them.  It is dry, incomplete, and sometimes wrong.  It is unlikely tobe useful for the general reader.  I&rsquo;m compiling it because I want a record ofwhat I learn, and I hope that writing documentation will help me do cleaner,more reproducible work.  If it helps people with similar problems along theway, so much the better.</p>
<p>&mdash; bpb / <a href="https://p1k3.com">p1k3</a>/ <a href="https://ello.co/brennen">@brennen</a>/ <a href="http://squiggle.city/~brennen/">~brennen</a></p>
<h2><a name=a-technical-notebook-copying href=#a-technical-notebook-copying>#</a> copying</h2>
<p><a href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA 4.0</a></p>
<div class=details>  <h2 class=clicker><a name=a-technical-notebook-contents href=#a-technical-notebook-contents>#</a> contents</h2>  <div class=full>    <div class=contents><ol><li><a href="#a-technical-notebook">a technical notebook</a>
<ul><li><a href="#a-technical-notebook-copying">copying</a></li><li><a href="#a-technical-notebook-contents">contents</a></li></ul></li><li><a href="#Wednesday-December-3-2014">Wednesday, December 3, 2014</a>
<ul><li><a href="#Wednesday-December-3-2014-makecitizen">makecitizen</a></li></ul></li><li><a href="#Friday-December-5-2014">Friday, December 5, 2014</a>
<ul><li><a href="#Friday-December-5-2014-notes-on-vim">notes on vim</a></li><li><a href="#Friday-December-5-2014-keybindings">keybindings</a></li></ul></li><li><a href="#Sunday-December-7-2014">Sunday, December 7, 2014</a>
<ul><li><a href="#Sunday-December-7-2014-notes-directory">notes directory</a></li></ul></li><li><a href="#Monday-December-8-2014">Monday, December 8, 2014</a>
<ul><li><a href="#Monday-December-8-2014-ssh">ssh</a></li><li><a href="#Monday-December-8-2014-mosh">mosh</a></li><li><a href="#Monday-December-8-2014-time-tracking">time tracking</a></li><li><a href="#Monday-December-8-2014-noobs-raspbian">noobs / raspbian</a></li><li><a href="#Monday-December-8-2014-beaglebone-black">beaglebone black</a></li><li><a href="#Monday-December-8-2014-reading-list">reading list</a></li></ul></li><li><a href="#Wednesday-December-10-2014">Wednesday, December 10, 2014</a>
<ul><li><a href="#Wednesday-December-10-2014-listusers-squiggle-city-repo">listusers / squiggle.city repo</a></li></ul></li><li><a href="#Thursday-December-18-2014">Thursday, December 18, 2014</a>
<ul><li><a href="#Thursday-December-18-2014-screencast-gifs">screencast gifs</a></li></ul></li><li><a href="#Friday-December-19-2014">Friday, December 19, 2014</a>
<ul><li><a href="#Friday-December-19-2014-drawing-tools">drawing tools</a></li></ul></li><li><a href="#Tuesday-December-23-2014">Tuesday, December 23, 2014</a>
<ul><li><a href="#Tuesday-December-23-2014-screenshots">screenshots</a></li></ul></li><li><a href="#Sunday-December-28-2014">Sunday, December 28, 2014</a>
<ul><li><a href="#Sunday-December-28-2014-candles-amp-candlemaking">candles &amp; candlemaking</a></li></ul></li><li><a href="#Saturday-January-3-2015">Saturday, January 3, 2015</a>
<ul><li><a href="#Saturday-January-3-2015-ipv6">ipv6</a></li></ul></li><li><a href="#Wednesday-January-7-2014">Wednesday, January 7, 2014</a>
<ul><li><a href="#Wednesday-January-7-2014-local-webservers-and-static-html-generation">local webservers and static html generation</a></li></ul></li><li><a href="#Monday-January-12">Monday, January 12</a>
<ul><li><a href="#Monday-January-12-Debian-packaging">Debian packaging</a></li><li><a href="#Monday-January-12-MS-DOS-AGT">MS-DOS / AGT</a></li></ul></li><li><a href="#Tuesday-January-13">Tuesday, January 13</a>
<ul><li><a href="#Tuesday-January-13-rtd-bus-schedules-transit-data">rtd / bus schedules / transit data</a></li></ul></li><li><a href="#Wednesday-January-14-2015">Wednesday, January 14, 2015</a></li><li><a href="#Friday-January-16">Friday, January 16</a></li><li><a href="#Tuesday-January-20">Tuesday, January 20</a></li><li><a href="#Thursday-January-22">Thursday, January 22</a>
<ul><li><a href="#Thursday-January-22-deleting-files-from-git-history">deleting files from git history</a></li><li><a href="#Thursday-January-22-postscript-on-finding-bugs">postscript:  on finding bugs</a></li></ul></li><li><a href="#Sunday-January-25-2015">Sunday, January 25, 2015</a>
<ul><li><a href="#Sunday-January-25-2015-background-colors-for-tmux">background colors for tmux</a></li></ul></li><li><a href="#Tuesday-January-27">Tuesday, January 27</a>
<ul><li><a href="#Tuesday-January-27-what-version-of-what-linux-distribution-is-this">what version of what linux distribution is this?</a></li><li><a href="#Tuesday-January-27-armhf">armhf</a></li></ul></li><li><a href="#Wednesday-January-28">Wednesday, January 28</a>
<ul><li><a href="#Wednesday-January-28-on-replicating-process">on replicating process</a></li><li><a href="#Wednesday-January-28-what-makes-programming-hard">what makes programming hard?</a></li><li><a href="#Wednesday-January-28-debian-packaging-again">debian packaging again</a></li><li><a href="#Wednesday-January-28-vagrant">vagrant</a></li></ul></li><li><a href="#Thursday-January-29">Thursday, January 29</a>
<ul><li><a href="#Thursday-January-29-raspberry-pi-kernels">raspberry pi kernels</a></li></ul></li><li><a href="#Monday-February-2">Monday, February  2</a>
<ul><li><a href="#Monday-February-2-kernel-o-matic-amp-pi-finder">kernel-o-matic &amp; pi finder</a></li><li><a href="#Monday-February-2-raspberry-pi-2">raspberry pi 2</a></li><li><a href="#Monday-February-2-telling-composer-to-ignore-php-version-requirements">telling composer to ignore php version requirements</a></li></ul></li><li><a href="#Sunday-February-8">Sunday, February  8</a>
<ul><li><a href="#Sunday-February-8-systemd-amp-fsck">systemd &amp; fsck</a></li></ul></li><li><a href="#Monday-March-2">Monday, March  2</a>
<ul><li><a href="#Monday-March-2-python">python</a></li></ul></li><li><a href="#Thursday-April-9">Thursday, April  9</a>
<ul><li><a href="#Thursday-April-9-CGI-Fast-and-multi-param">CGI::Fast and multi_param()</a></li></ul></li><li><a href="#Monday-April-20">Monday, April 20</a>
<ul><li><a href="#Monday-April-20-getting-recent-posts-from-pinboard-machine-readably">getting recent posts from pinboard machine-readably</a></li></ul></li><li><a href="#Monday-January-18">Monday, January 18</a>
<ul><li><a href="#Monday-January-18-moved-to-p1k3-com">moved to p1k3.com</a></li></ul></li><li><a href="#tools-amp-toolchains-for-data-munging-amp-analysis">tools &amp; toolchains for data munging &amp; analysis</a>
<ul><li><a href="#tools-amp-toolchains-for-data-munging-amp-analysis-csvkit">csvkit</a></li><li><a href="#tools-amp-toolchains-for-data-munging-amp-analysis-jq">jq</a></li></ul></li><li><a href="#systemd-notes">systemd notes</a></li></ol>
</div>  </div></div>


</article>


<article>
<h1><a name=Wednesday-December-3-2014 href=#Wednesday-December-3-2014>#</a> Wednesday, December 3, 2014</h1>
<h2><a name=Wednesday-December-3-2014-makecitizen href=#Wednesday-December-3-2014-makecitizen>#</a> makecitizen</h2>
<p>{sysops, scripting, adduser, chfn}</p>
<p>Paul Ford sent out an e-mail to the tilde.club waitlist pointing at~pfhawkins&rsquo;s list of other tildes, so I&rsquo;m getting signup requests.  There areenough that I want to write a script for adding a new squiggle.city user.  I&rsquo;mnot determined to be very fancy about this right now; I just want to save somekeystrokes.</p>
<p>The first thing I do is google &ldquo;adduser&rdquo;.  <code>adduser(1)</code> is basically just afront end to <code>useradd(1)</code>.  (This distinction will never stop being confusing,and should probably be a lesson to anyone considering that naming pattern.)  Ilearn via Wikipedia that the metadata (name, room number, phone, etc.) whichadduser prompts for is called the<a href="http://en.wikipedia.org/wiki/Gecos_field">GECOS field</a>, and is a relic of somethingcalled the General Electric Comprehensive Operating System, which ran on somemachines at Bell Labs.</p>
<p>You can change that info with <code>chfn(1)</code>.</p>
<p>What my script needs to do is:</p>
<ol><li>create a user with a given <code>$USERNAME</code></li><li>generate a random password for the user and tell me</li><li>do <code>chage -d0 $USERNAME</code></li><li>put a given public key in <code>~$USERNAME/.ssh/authorized_keys</code></li></ol>

<p>You can&rsquo;t log in to squiggle.city with a password, so why go to the trouble ofsetting a random one and forcing users to change it at their first login?Mostly because users are going to need to know a password for things likechanging their shell or in the case that they get operator privileges one day.</p>
<p>This is what I come up with, after a couple of even dumber iterations:</p>
<pre><code>#!/bin/bash
CITIZEN=$1KEYSTRING=$2
# Complain and exit if we weren't given a path and a property:if [[ ! $CITIZEN || ! $KEYSTRING ]]; then  echo "usage: makecitizen &lt;username&gt; &lt;key&gt;"  exit 64fi
# this should actually check if a _user_ exists,# not just the homedirif [ -d /home/$CITIZEN ]; then  echo "$CITIZEN already exists - giving up"  exit 68fi
PASSWORD=`apg -d -n2`
adduser --disabled-login $CITIZENecho "$CITIZEN:$PASSWORD" | chpasswdchage -d 0 $CITIZEN
echo "$KEYSTRING" &gt;&gt; /home/$CITIZEN/.ssh/authorized_keys  
echo "passwd: $PASSWORD"
exit 0</code></pre>
<p>This is used like so:</p>
<pre><code>root@squiggle:~# ./makecitizen jrandomuser "ssh-rsa ..."</code></pre>
<p>It&rsquo;ll still do <code>adduser</code> interactively, which is fine for my purposes.</p>
<p>I think this would be improved if it took a fullname and e-mail as input,and then sent that person a message, or at least output the text of one,telling them their password.</p>
<p>It&rsquo;d probably be improved even more than that if it operated in batch mode, wastotally idempotent, and could be driven off some separate file or outputcontaining the set of users.</p>
<p>(Thoughts like this are how systems like Puppet and Chef are born.)</p>

</article>


<article>
<h1><a name=Friday-December-5-2014 href=#Friday-December-5-2014>#</a> Friday, December 5, 2014</h1>
<h2><a name=Friday-December-5-2014-notes-on-vim href=#Friday-December-5-2014-notes-on-vim>#</a> notes on vim</h2>
<p>Vim is a text editor.  My slowly-evolving configuration can be found on GitHub,in <a href="https://github.com/brennen/bpb-kit">bpb-kit</a>.</p>
<p><a href="https://github.com/thcipriani/">Tyler Cipriani</a> is a lot smarter than I am about vim (and, infact, most things), but I am particular and don&rsquo;t always share his preferences.</p>
<h2><a name=Friday-December-5-2014-keybindings href=#Friday-December-5-2014-keybindings>#</a> keybindings</h2>
<p>I&rsquo;m starting in on this notebook, which uses a Makefile, and think it might benice to have a quick vim keybinding for <code>:make</code>.  I would use <code>F5</code>, by analogyto QBasic, but I&rsquo;ve already bound that to <code>:wall</code>, which writes all the openbuffers with changes.</p>
<p>I think that maybe <code>&lt;leader&gt;m</code>, which in my case means <code>,m</code>, would be ok.  ThenI&rsquo;m not sure if something is already mapped starting with that, so I try <code>:map</code>.</p>
<p>I want to search through the list produced by <code>:map</code>, and think it&rsquo;d be nice ifI could just read it into a buffer.  The first thing I google is &ldquo;vim readoutput of command into file&rdquo;.  This could easily enough give hits for readingthe output of a shell command, but the 3rd thing down the page is<a href="http://vim.wikia.com/wiki/Capture_ex_command_output">Capture ex command output</a>on the Vim Tips Wiki.</p>
<p>There are a bunch of interesting ideas there, but the first basic idea is this:</p>
<pre><code>:redir @a:set all:redir END</code></pre>
<p>Then you can open a new buffer - <code>:new</code> - and do <code>"ap</code>.  This says &ldquo;using the namedregister a, paste&rdquo;.</p>
<p>This seems to work with <code>:set all</code>, but not so much with <code>:map</code>.  Why not?  I skim<code>:help map</code> and <code>help redir</code> without getting very far.  Updates to come.</p>
<p>With that digression still unanswered, the mapping I settled on is simple:</p>
<pre><code>nmap &lt;leader&gt;m :make&lt;CR&gt;</code></pre>
<p>I never know if these are going to take with me.  The handful of custombindings that have actually entered my vocabulary are super-useful, but moreoften than not I wind up forgetting about an idea not long after I&rsquo;veimplemented it.</p>

</article>


<article>
<h1><a name=Sunday-December-7-2014 href=#Sunday-December-7-2014>#</a> Sunday, December 7, 2014</h1>
<h2><a name=Sunday-December-7-2014-notes-directory href=#Sunday-December-7-2014-notes-directory>#</a> notes directory</h2>
<p>On organizing todo lists, see <a href="https://p1k3.com/2014/8/23">the p1k3 entry from August of2014</a>.</p>
<p>For years now, I&rsquo;ve kept that sort of thing in a <code>notes.txt</code>.  At some pointnotes.txt got its own directory with a haphazard jumble of auxiliary files.  Itlooks like I turned that directory into a git repository a couple of years ago.</p>
<p>Unlike a lot of what I keep in git, <code>~/notes/</code> isn&rsquo;t meant for any kind ofpublication.  In fact, it&rsquo;d be pretty dumb to let it out in the world.  So I gotto thinking:  I should really encrypt this.</p>
<p>So what&rsquo;s the best way to encrypt a single directory on Linux?</p>
<p>Two search strings:</p>
<ul><li>linux encrypted directory</li><li>encrypted git repo</li></ul>

<p>It looks like maybe [<a href="http://ecryptfs.org/">http://ecryptfs.org/</a>][eCryptFS] is the thing?  This machine&rsquo;s anUbuntu, so let&rsquo;s see what we can find:</p>
<pre><code>$ apt-cache search ecryptfsecryptfs-utils - ecryptfs cryptographic filesystem (utilities)ecryptfs-utils-dbg - ecryptfs cryptographic filesystem (utilities; debug)libecryptfs-dev - ecryptfs cryptographic filesystem (development)libecryptfs0 - ecryptfs cryptographic filesystem (library)python-ecryptfs - ecryptfs cryptographic filesystem (python)zescrow-client - back up eCryptfs Encrypted Home or Encrypted Private Configuration</code></pre>
<p>Google suggests that ecryptfs-utils might be what I&rsquo;m looking for.</p>
<p>I become distracted reading about protests and leave this idea for another day.</p>

</article>


<article>
<h1><a name=Monday-December-8-2014 href=#Monday-December-8-2014>#</a> Monday, December 8, 2014</h1>
<h2><a name=Monday-December-8-2014-ssh href=#Monday-December-8-2014-ssh>#</a> ssh</h2>
<p>I use SSH for damn near everything.  We need SSH for damn near everything.</p>
<p>I have this thought that SSH is quite possibly the only end-user-exposedimplementation of acceptable crypto in wide use which actually satisfies the&ldquo;actual human beings can use this&rdquo; constraint at the same time as satisfyingthe &ldquo;this makes your shit relatively secure&rdquo; constraint.  That&rsquo;s not to sayit&rsquo;s easy for the average mortal to comprehend, but it beats the shit out ofalmost everything else I can think of.</p>
<p>In &ldquo;almost everything else&rdquo;, I include SSL/TLS/HTTPS, which sort-of works asfar as the general user population of browsers is concerned, much of the time,but which is an absolute nightmare to administer and which is a fundamentallybroken design on a political / systems-of-control / economic /regular-admins-get-this-right level.  Arguably, the only thing that has beenworse for the wide adoption of crypto by normal users than SSL/TLS is PGP.</p>
<p>DISCLAIMER:  I DON&rsquo;T KNOW SHIT ABOUT CRYPTO.  Tell me how I&rsquo;m wrong.</p>
<p style="text-align:center;"> ✴</p>
<ul><li>&ldquo;<a href="http://harmful.cat-v.org/software/ssh">Sorry Theo, but SSH Sucks</a>&rdquo;</li></ul>

<h2><a name=Monday-December-8-2014-mosh href=#Monday-December-8-2014-mosh>#</a> mosh</h2>
<p>I&rsquo;m not exactly sure when mosh started to catch on with people I know, but I&rsquo;dsay it&rsquo;s on the order of a year or two that I&rsquo;ve been aware of it.  The basicthing here is that it&rsquo;s essentially OpenSSH with better characteristics for aspecific cluster of use cases:</p>
<ul><li>laggy, high-latency, intermittently-broken network connections</li><li>client machines that frequently hop networks and/or suspend operations</li><li>unreliable VPNs (which is to say very nearly all VPNS in actual use)</li></ul>

<h2><a name=Monday-December-8-2014-time-tracking href=#Monday-December-8-2014-time-tracking>#</a> time tracking</h2>
<p>I&rsquo;m about to start in on some remote contracting stuff, so I go looking for atime tracking tool.  For the moment I settle on this little tray widget called<a href="http://projecthamster.wordpress.com/">hamster</a>, which looks functional if notprecisely inspiring.</p>
<h2><a name=Monday-December-8-2014-noobs-raspbian href=#Monday-December-8-2014-noobs-raspbian>#</a> noobs / raspbian</h2>
<p>Last year I did a bunch of work on a Raspberry Pi, but it&rsquo;s been a few monthssince I booted one up.  I got a model B+ (more USB ports, various hardwaretweaks, takes a microSD card instead of the full-size one) in my last employeeorder at SparkFun, and I&rsquo;m stepping through what seems to be the stockrecommended installation process.</p>
<ul><li><a href="http://www.raspberrypi.org/new-raspbian-and-noobs-releases/">http://www.raspberrypi.org/new-raspbian-and-noobs-releases/</a></li><li><a href="http://www.raspberrypi.org/downloads/">http://www.raspberrypi.org/downloads/</a></li><li><a href="http://downloads.raspberrypi.org/NOOBS_latest.torrent">http://downloads.raspberrypi.org/NOOBS_latest.torrent</a></li></ul>

<p>I torrented <code>NOOBS_v1_3_10.zip</code>.  Be careful unzipping this one - everything is atthe top level of the archive (advice to distributors of basically anything:  don&rsquo;tdo that).</p>
<p>If I&rsquo;d been smart I probably would have done:</p>
<pre><code>$ mkdir noobs &amp;&amp; unzip NOOBS_v1_3_10.zip -d noobs/</code></pre>
<p>The basic system here is &ldquo;get an SD card, put the stuff in this zip file on theSD card, put it in the Pi&rdquo;.  Everything about this has always felt kind ofweird (if not actively broken) to me, but it&rsquo;s probably important to rememberthat for most users &ldquo;put some files on this media&rdquo; is a lot easier than &ldquo;imagethis media with the filesystem contained in this file&rdquo;.</p>
<p style="text-align:center;"> ✩</p>
<p>So I plug in all the stuff:  microSD card, keyboard, HDMI cable to random sparemonitor, power.</p>
<p>Nothing.  Well, almost nothing.  Blinkenlights, no video output.  Red light issteady, green light blinks a couple of times periodically.</p>
<p>I am reminded that this is, fundamentally, a terrible piece of hardware.</p>
<p>Power down, remove SD card, mount SD card on Linux machine, google variously,delete and recreate FAT32 partition using gparted, re-copy NOOBS files, unmountSD card, replace card in Pi, re-apply power.</p>
<p>Green LED flashes spasmodically for a bit then seems mostly off, but is actuallyflickering faintly on closer examination.  Red light is solid.</p>
<p><a href="http://elinux.org/R-Pi_Troubleshooting#Red_power_LED_is_on.2C_green_LED_does_not_flash.2C_nothing_on_display">This wiki page</a>suggests this means that no boot code has been executed at all.  It&rsquo;s failing toread the card, or it&rsquo;s missing some file, or something is corrupt.</p>
<p>Ok, so, mount SD card on Linux machine again; immediately discover that thecard is now a volume called &ldquo;SETTINGS&rdquo;, or seems to be.</p>
<pre><code>$ ls /media/brennen/SETTINGSlost+foundnoobs.conf
$ cat /media/brennen/SETTINGS/noobs.conf[General]display_mode=0keyboard_layout=gblanguage=en
brennen@desiderata 15:52:24 /home/brennen ★ sudo parted /dev/mmcblk0GNU Parted 2.3Using /dev/mmcblk0Welcome to GNU Parted! Type 'help' to view a list of commands.(parted) printModel: SD SL16G (sd/mmc)Disk /dev/mmcblk0: 15.9GBSector size (logical/physical): 512B/512BPartition Table: msdos
Number  Start   End     Size    Type      File system  Flags 1      1049kB  823MB   822MB   primary   fat32        lba 2      826MB   15.9GB  15.1GB  extended 3      15.9GB  15.9GB  33.6MB  primary   ext4
(parted)</code></pre>
<p>Well, obviously something ran, because I definitely didn&rsquo;t arrange anythingthat way.  And this seems a little telling:</p>
<pre><code>brennen@desiderata 15:55:36 /home/brennen ★ dmesg | tail -12[51329.226687] mmc0: card aaaa removed[51776.154562] mmc0: new high speed SDHC card at address aaaa[51776.154894] mmcblk0: mmc0:aaaa SL16G 14.8 GiB [51776.169240]  mmcblk0: p1 p2 &lt; &gt; p3[51781.342106] EXT4-fs (mmcblk0p3): mounted filesystem with ordered data mode. Opts: (null)[51791.757878] mmc0: card aaaa removed[51791.773880] JBD2: Error -5 detected when updating journal superblock for mmcblk0p3-8.[51793.651277] mmc0: new high speed SDHC card at address aaaa[51793.651601] mmcblk0: mmc0:aaaa SL16G 14.8 GiB [51793.666335]  mmcblk0: p1 p2 &lt; &gt; p3[51799.516813] EXT4-fs (mmcblk0p3): recovery complete[51799.518183] EXT4-fs (mmcblk0p3): mounted filesystem with ordered data mode. Opts: (null)</code></pre>
<p>(The &ldquo;Error -5 detected bit.)</p>
<p>Ok, so I bought a new Sandisk-branded card because I didn&rsquo;t have a decentlyfast microSD card laying around.  What I&rsquo;m going to check before I go anyfurther is whether I got one the Pi can&rsquo;t deal with.  (Or just one that&rsquo;s bunk.I bought this thing for 15 bucks at Best Buy, so who knows.)</p>
<p>Here&rsquo;s an 8 gig class 4 card, branded Kingston, but I probably got it off theshelves at SparkFun some time in the last 3 years, so its actual provenance isanybody&rsquo;s guess.  Looking at what&rsquo;s on here, I&rsquo;ve already used it for aRaspberry Pi of some flavor in the past.  Let&rsquo;s see if it&rsquo;ll boot as-is.</p>
<p>Ok, no dice.  I&rsquo;m starting to suspect my problem lies elsewhere, but I&rsquo;ll tryone more time on this card with NOOBS.</p>
<p>Again:  No dice.</p>
<p>Also checked:</p>
<ul><li>the monitor with other inputs, because who knows</li><li>tried a couple of different power supplies - USB cable from my laptop, 5Vwall wart purchased from SFE, cell phone charger.</li><li>the usual plug-things-in-one-at-a-time routine.</li></ul>

<p style="text-align:center;"> ✦</p>
<p>Time to try one of these cards with an older RasPi, if I can figure out where Iput any of them.</p>
<p>After much shuffling through stuff on my dining room table / workbench, I finda model B.  It fails in much the same way, which leads me to suspect again thatI&rsquo;m doing something wrong with the card, but then I can&rsquo;t quite remember ifthis one still worked the last time I plugged it in.  They can be fragilelittle critters.</p>
<p>Here&rsquo;s a thought, using a Raspbian image I grabbed much earlier this year:</p>
<pre><code>brennen@desiderata 17:10:03 /home/brennen/isos ★ sudo dd if=/home/brennen/isos/2014-01-07-wheezy-raspbian.img of=/dev/mmcblk0</code></pre>
<p>No dice on either the model B or model B+, using the new SanDisk.</p>
<p>Trying with the older card, <code>dd</code> spins through 800ish megs before giving me an I/O error.</p>
<p>It may be time to start drinking.</p>
<p style="text-align:center;"> ✦</p>
<p>The next day:  I swing through a couple of stores in town with the <a href="http://www.raspberrypi.org/forums/viewtopic.php?t=58151">wiki listof known cards in hand</a> and buy a pileof cards across a handful of brands, plus a $20 card reader (the InsigniaNS-CR20A1) since there&rsquo;s not one built in to the laptop I&rsquo;m carrying today.The first card I try boots NOOBS instantly; an installer is running as I typethis.</p>
<p>Suddenly It occurs to me that the card reader on the laptop I was using lastnight might is likely dying/dead.</p>
<p>This is a really slick install process now, so good work to somebody on that.</p>
<h2><a name=Monday-December-8-2014-beaglebone-black href=#Monday-December-8-2014-beaglebone-black>#</a> beaglebone black</h2>
<p>I&rsquo;ve got a Beaglebone Black sitting here new in the box.  It comes with a USBcable, so I plug it in.  Instantly there are bright blue blinky lights, and mylaptop tells me I&rsquo;m connected to an ethernet network and I&rsquo;ve got a new drivemounted with some README files in it.</p>
<p>This is kind of great.</p>
<p>Browsing to to 192.168.7.2 gets a bunch of docs and a link to Cloud9, anin-browser IDE that happens to include a root terminal.</p>
<p>I don&rsquo;t really know what&rsquo;s going on here.  I think it might be a littlescattered and confused as a user experience, in some ways.  But it immediatelystrikes me as good tech in a bunch of ways.</p>
<p>Josh Datko, who I&rsquo;ve gotten to know a little bit, has a book called <em>Beaglebonefor Secret Agents</em>.  It&rsquo;s been on my ever-growing to-read list for a while; I&rsquo;mgoing to have to give it a look sooner rather than later.</p>
<h2><a name=Monday-December-8-2014-reading-list href=#Monday-December-8-2014-reading-list>#</a> reading list</h2>
<ul><li><a href="http://www.jann.cc/2013/01/15/trying_out_the_adafruit_webide.html">http://www.jann.cc/2013/01/15/trying_out_the_adafruit_webide.html</a></li><li><a href="http://www.angstrom-distribution.org/">http://www.angstrom-distribution.org/</a></li><li><a href="http://www.raspberrypi.org/documentation/configuration/config-txt.md">http://www.raspberrypi.org/documentation/configuration/config-txt.md</a></li></ul>


</article>


<article>
<h1><a name=Wednesday-December-10-2014 href=#Wednesday-December-10-2014>#</a> Wednesday, December 10, 2014</h1>
<h2><a name=Wednesday-December-10-2014-listusers-squiggle-city-repo href=#Wednesday-December-10-2014-listusers-squiggle-city-repo>#</a> listusers / squiggle.city repo</h2>
<p>There&rsquo;s now a <a href="https://github.com/squigglecity/">squigglecity organization on GitHub</a>.What little is there is a classic duct-tape mess complete with a bunch ofcommits made as root, but may contain a few useful bits.</p>
<p>I&rsquo;m planning to clean up <a href="https://github.com/squigglecity/squiggle.city/blob/1a07ccc8415b05ad239116a062d2992ae1537541/listusers.pl">this version of listusers.pl</a> into amore generic <code>listusers</code> utility that just outputs TSV and pipe to csvkit / <code>jq</code>for HTML &amp; JSON.</p>
<p>Oh, right &mdash; about the JSON.  ~ford proposed a standard <code>tilde.json</code> <a href="http://squiggle.city/tilde.json">kind oflike this</a>, which I think is not a terribleidea at all though that one&rsquo;s a bit rough and the format could still use alittle tweaking as of this writing.</p>
<p>This is the kind of thing it&rsquo;s unbelievably easy to overthink.  I&rsquo;m hopingwe&rsquo;ll give it enough thought to do a few smart things but not so much thoughtthat no one actually uses it.</p>

</article>


<article>
<h1><a name=Thursday-December-18-2014 href=#Thursday-December-18-2014>#</a> Thursday, December 18, 2014</h1>
<h2><a name=Thursday-December-18-2014-screencast-gifs href=#Thursday-December-18-2014-screencast-gifs>#</a> screencast gifs</h2>
<p>Looking to make some GIFs of things that happen on my screen, found <code>byzanz</code>.</p>
<pre><code>$ sudo apt-get install byzanzbyzanz-record -x 1 -y 1 --delay=4 -h 150 -w 700 hello_world.gif</code></pre>
<p>Options:</p>
<ul><li><code>-x</code> and <code>-y</code> set origin of capture on screen</li><li><code>-h</code> and <code>-w</code> set height and width to capture</li></ul>

<p>I think I need a more clever way to trigger / manage this than just fiddlingwith CLI options, but it works really well and produces lightweight imagefiles.</p>
<p>I think it would be cool if there were a utility that let me use arrow keys /hjkl / the mouse cursor to visually select a region of the screen.  It couldreturn x, y, height, and width, then I&rsquo;d let byzanz handle the capture.</p>
<p>That can&rsquo;t be the <em>hardest</em> thing in the world to do.</p>
<p style="text-align:center;"> ☆</p>
<p><a href="http://www.semicomplete.com/projects/xdotool/">xdotool</a> seems like kind of aswiss army knife, and has a <code>getmouselocation</code> command.  Theoretically, atleast, you can have it respond to events, including a mouse click.  I can&rsquo;tquite wrap my head around how this is supposed to work, and my first fewattempts fall flat.</p>
<p><a href="https://www.gnu.org/software/xnee/">GNU xnee</a> might also be promising, but Idon&rsquo;t really get anywhere with it.</p>
<p>Eventually I find an<a href="http://askubuntu.com/questions/107726/how-to-create-animated-gif-images-of-a-screencast">Ask Ubuntu</a>thread on creating screencast gifs, which points to<a href="https://github.com/lolilolicon/xrectsel">xrectsel</a>, a tool forreturning the coordinates and size of a screen region selected with the mouse:</p>
<pre><code>brennen@desiderata 22:06:28 /var/www/workings-book (master) ★  xrectsel "%x %y %w %h"432 130 718 575%</code></pre>
<p>I wind up with <a href="https://github.com/brennen/bpb-kit/blob/master/bin/gif_sel"><code>gif_sel</code></a>:</p>
<pre><code>#!/usr/bin/env bash
# requires:# https://github.com/lolilolicon/xrectsel.git
eval `xrectsel "BYZANZ_X=%x; BYZANZ_Y=%y; BYZANZ_WIDTH=%w; BYZANZ_HEIGHT=%h"`byzanz-record -x $BYZANZ_X -y $BYZANZ_Y --delay=4 -h $BYZANZ_HEIGHT -w $BYZANZ_WIDTH ~/screenshots/screencast-`date +"%Y-%m-%d-%T"`.gif</code></pre>
<p>I&rsquo;ll probably wind up with a couple of wrappers for this for different lengthsof recording (for starting with dmenu), though it would be nice if I could justhave it record until I press some hotkey.</p>

</article>


<article>
<h1><a name=Friday-December-19-2014 href=#Friday-December-19-2014>#</a> Friday, December 19, 2014</h1>
<p>{timetracking}</p>
<p>So hamster really doesn&rsquo;t scratch my particular itch all that well.  Ratherthan devote any serious brain energy to finding or writing a replacement thatdoes, I&rsquo;ve decided to just use a text file.</p>
<p>It looks like the following:</p>
<pre><code>2014-12-17 21:55 - 2014-12-17 11:402014-12-18 10:05 - 2014-12-18 12:502014-12-18 13:45 - 2014-12-18 16:00</code></pre>
<p>This is just two datetimes for each range of time when I&rsquo;m working on a giventhing, delimited by <code>/ - /</code>.  I just want a quick script to tally the timerepresented.  (Later, if I need to track more than one project, I&rsquo;ll expand onthis by adding a project name and/or notes to the end of the line.)</p>
<p>It kind of seems like I should be able to do this with GNU <code>date</code>, but let&rsquo;sfind out.  Here&rsquo;re the <a href="https://www.gnu.org/software/coreutils/manual/html_node/Examples-of-date.html">official examples</a>.  This sounds aboutright:</p>
<blockquote><p>To convert a date string to the number of seconds since the epoch (which is1970-01-01 00:00:00 UTC), use the &ndash;date option with the ‘%s’ format. Thatcan be useful in sorting and/or graphing and/or comparing data by date. Thefollowing command outputs the number of the seconds since the epoch for thetime two minutes after the epoch:</p>
<pre><code>    date --date='1970-01-01 00:02:00 +0000' +%s    120</code></pre></blockquote>
<p>As a test case, I start here:</p>
<pre><code>$ cat ~/bin/timelog#!/usr/bin/env bash
date --date="$1" +%s
$ timelog '2014-12-17 21:55'1418878500</code></pre>
<p>Ok, groovy.</p>
<p>I was going to do the rest of this in shell or awk or something, but then Ithought &ldquo;I should not spend more than 10 minutes on this&rdquo;, and wrote the followingPerl:</p>
<pre><code>#!/usr/bin/env perl
use warnings;use strict;use 5.10.0;
my $total_hours = 0;
# while we've got input from a file/stdin, split it into two datestamps# and feed that to date(1)while (my $line = &lt;&gt;) {  chomp($line);  my ($start, $end) = map { get_seconds($_) } split / - /, $line;  my $interval = $end - $start;  my $hours = $interval / 3600;  $total_hours += $hours;  say sprintf("$line - %.3f hours", $hours);}
say sprintf("%.3f total hours", $total_hours);
sub get_seconds {  my ($stamp) = @_;  my $seconds = `date --date="$stamp" +%s`;  chomp($seconds);  return $seconds;}</code></pre>
<p>Which gives this sort of output:</p>
<pre><code>brennen@desiderata 14:54:38 /home/brennen/bin (master) ★ timelog ~/notes/some_employer.txt2014-12-15 13:10 - 2014-12-15 14:35 - 1.417 hours2014-12-16 10:00 - 2014-12-16 12:55 - 2.917 hours2014-12-16 14:00 - 2014-12-16 17:15 - 3.250 hours2014-12-17 15:00 - 2014-12-17 16:51 - 1.850 hours2014-12-17 21:55 - 2014-12-17 23:40 - 1.750 hours2014-12-18 10:05 - 2014-12-18 12:50 - 2.750 hours2014-12-18 13:45 - 2014-12-18 16:00 - 2.250 hours2014-12-18 17:00 - 2014-12-18 17:30 - 0.500 hours16.683 total hours</code></pre>
<p>This is me once again being lazy and treating Perl as a way to wrap shellutilities when I want to easily chop stuff up and do arithmetic.  It is <em>manykinds of wrong</em> to do things this way, but right now I don&rsquo;t care.</p>
<p>If this were going to be used by anyone but me I would do it in pure-Perl andmake it robust against stupid input.</p>
<h2><a name=Friday-December-19-2014-drawing-tools href=#Friday-December-19-2014-drawing-tools>#</a> drawing tools</h2>
<p>Ok, so because I&rsquo;m starting to poke at drawing again for the first time inquite a while (even to the extent that I&rsquo;ll soon be publishing some stuff thatincludes cartoon graphics, despite having <em>no</em> idea what I&rsquo;m doing), I thoughtI&rsquo;d take some rough notes on where I&rsquo;m at with toolset.</p>
<p>The first thing is that I&rsquo;m not using any Adobe tools, or indeed anyproprietary software (unless you count the firmware on my cameras and maybeFlickr) to work with images.  I am fully aware that this is a <em>ridiculous</em>limitation to self-impose, but I want to stick with it as best I can.</p>
<p>For a long time, I&rsquo;ve sort of fumbled my way through GIMP whenever I needed todo the kind of light image editing stuff that inevitably comes up in the lifeof a web developer no matter how many things you foist off on yourPhotoshop-skilled, design-happy coworkers.  I think GIMP gets kind of an unfairrap; it&rsquo;s a pretty capable piece of software.  That said, I&rsquo;ve still neverreally put the time in to get genuinely skilled with it, and it&rsquo;s not the mostaccessible thing for just doodling around.</p>
<p>Several years back, I <a href="https://p1k3.com/2011/4/13">bought a cheap Wacom tablet</a>.I was maybe a little optimistic in that writeup, but I still really enjoy<a href="http://mypaint.intilinux.com/">MyPaint</a>.  The problem is that, while it&rsquo;s reallyfun for a sketchy/painty/extemperaneous kind of workflow, and dovetailsbeautifully with the tablet interface, it deliberately eschews a lot of featuresthat you start to want for <em>editing</em> an image.  I don&rsquo;t blame its developers forthat &mdash; they&rsquo;re obviously trying to do a certain kind of thing, and constraintsoften make for great art &mdash; but I&rsquo;m wondering if I can&rsquo;t get some of the samevibe with a tool that also lets me easily cut/copy/scale stuff.</p>
<p>I&rsquo;m giving <a href="https://krita.org/">Krita</a> a shot with that in mind.  It has a realKDE vibe to it.  Lots of modular GUI widgets, menus, etc.  A littlebureaucratic.  It doesn&rsquo;t feel as fluid or immediate as MyPaint right out ofthe gate, but it&rsquo;s definitely got more in the way of features.  Could grow onme.</p>

</article>


<article>
<h1><a name=Tuesday-December-23-2014 href=#Tuesday-December-23-2014>#</a> Tuesday, December 23, 2014</h1>
<h2><a name=Tuesday-December-23-2014-screenshots href=#Tuesday-December-23-2014-screenshots>#</a> screenshots</h2>
<p>Looking to streamline capture of static screenshots a bit.  Options:</p>
<ul><li><code>gnome-screenshot</code> - use this already, it&rsquo;s fine, whatever.</li><li><code>shutter</code> - weirdness with my xmonad setup?  Errors and I don&rsquo;t feel like takingthe time to find out why.</li><li><code>scrot</code> - buncha nice command line options</li></ul>

<p>I wind up forking Tyler&rsquo;s <a href="https://github.com/thcipriani/dotfiles/blob/master/bin/grab">grab</a>,a nice wrapper for <code>scrot</code>, which is pretty much what I was going to write anyway.</p>
<p>This is pretty good at defining a region for a static screenshot.</p>

</article>


<article>
<h1><a name=Sunday-December-28-2014 href=#Sunday-December-28-2014>#</a> Sunday, December 28, 2014</h1>
<h2><a name=Sunday-December-28-2014-candles-amp-candlemaking href=#Sunday-December-28-2014-candles-amp-candlemaking>#</a> candles &amp; candlemaking</h2>
<p>A year ago at Christmastime, I decided to see what kind of candlemakingsupplies were still at my parents' house, and wound up digging a couple of bigRubbermaid tubs worth of molds, dyes, additives, wick, wax, &amp;c out of thebasement.</p>
<p>I used to do this a lot, but I&rsquo;ve mostly forgotten the details of technique.</p>
<p>Rough notes:</p>
<ul><li>Wax temperature when pouring is important.  I&rsquo;m aiming for 210-220 Fwith metal molds, but it&rsquo;s hard to get there with the little hot plate I&rsquo;musing.  I can usually get it just over 200, according to the thermometerI&rsquo;ve got.  This doesn&rsquo;t seem to be doing too much damage, but I do thinkthe results would be a little better with hotter wax.</li><li>You&rsquo;re supposed to use a proper double boiler or a purpose-built wax melter.I put various sizes of can in some water in a medium size pan.</li><li>I remember that I used to melt wax on the woodstove in my dad&rsquo;s shop, but ifso we must have been running the stove hotter in those days or I had a lotmore patience.  it does work well for holding wax at a reasonabletemperature until you have to do a second pour.</li><li>With metal molds, keeping the wax from streaming out the wick hole at thebottom is often kind of problematic.  I think you&rsquo;re supposed to affix thewicking with a little screw and put some tacky putty-type stuff over thescrew, but if you&rsquo;re low on the putty or don&rsquo;t have just the right sizescrew this doesn&rsquo;t work so great.  Things tried this time around:  Theremaining putty and then everything kind of smashed down on a wood block(Ben&rsquo;s idea), pouring a little wax in the bottom and letting it harden first,the wrong size screw, silicone caulk.  The wood block and the silicone caulkboth worked pretty well.</li><li>You can dye beeswax, but you have to keep in mind that the stuff is alreadypretty yellow and opaque.  Shades of green work well.  Other colors&hellip;  Well,I wound up with some the color of a strange weird woodland fungus.</li><li>Last time I did this, I wound up with a bunch of pillars that burned reallypoorly and with a small flame.  I think I wasn&rsquo;t using a heavy enough wick.Tried to go with heavier braided wicking this time.  Guess I&rsquo;ll see how thatpans out.</li></ul>


</article>


<article>
<h1><a name=Saturday-January-3-2015 href=#Saturday-January-3-2015>#</a> Saturday, January 3, 2015</h1>
<h2><a name=Saturday-January-3-2015-ipv6 href=#Saturday-January-3-2015-ipv6>#</a> ipv6</h2>
<p>I was hanging out on the internet and heard that <a href="&#109;&#97;&#105;&#108;&#116;&#111;&#58;&#105;&#109;&#116;&#64;&#112;&#114;&#111;&#116;&#111;&#99;&#111;&#108;&#46;&#99;&#108;&#117;&#98;">&#105;&#109;&#116;&#64;&#112;&#114;&#111;&#116;&#111;&#99;&#111;&#108;&#46;&#99;&#108;&#117;&#98;</a> had set up<a href="https://club6.nl">club6.nl</a>, a tildebox reachable only over ipv6.  I appliedfor an account and <a href="https://club6.nl/~brennen">got one</a> (very speedy turnaround,<a href="https://club6.nl/~imt/">~imt</a>).</p>
<p>The next problem was how to connect.  I am an utter prole when it comes tonetworking.  The first thing I remembered was that DigitalOcean optionallysupports ipv6 when creating a new droplet, and sure enough theyalso <a href="https://www.digitalocean.com/community/tutorials/how-to-enable-ipv6-for-digitalocean-droplets">have a guide for enabling it</a> on existing droplets.</p>
<p>TODO: Get my own sites resolving and reachable via ipv6.</p>

</article>


<article>
<h1><a name=Wednesday-January-7-2014 href=#Wednesday-January-7-2014>#</a> Wednesday, January 7, 2014</h1>
<h2><a name=Wednesday-January-7-2014-local-webservers-and-static-html-generation href=#Wednesday-January-7-2014-local-webservers-and-static-html-generation>#</a> local webservers and static html generation</h2>
<p>I haven&rsquo;t always run an httpd on my main local machine, but I&rsquo;ve been doing itagain for the last year or two now, and it feels like a major help.  I startedby setting up a development copy of <a href="https://github.com/brennen/display">display</a> under Apache, then noticedthat it was kind of nice to use it for static files.  I&rsquo;m not sure why it&rsquo;s anybetter than accessing them via the filesystem, except maybe that<code>localhost/foo</code> is easier to type than <code>file://home/brennen/something/foo</code>, butit has definitely made me better at checking things before I publish them.</p>
<p>(Why Apache? Well, it was easier to re-derive the configuration I needed forp1k3 things under Apache than write it from scratch under nginx, although oneof these days I may make the leap anyway.  I don&rsquo;t see any reason Perl FastCGIshouldn&rsquo;t work under nginx.  I also still think Apache has its merits, thoughmost of my domain knowledge has evaporated over the last few years of doingmainly php-fpm under nginx.)</p>
<p>I&rsquo;ve resisted the static blog engine thing for a long time now, but lately myfavorite way to write things is a super-minimal <code>Makefile</code>, some files inMarkdown, and a little bit of Perl wrapping <code>Text::Markdown::Discount</code>.  Ihaven&rsquo;t yet consolidated all these tools into a single generically reusablepiece of software, but it would probably be easy enough, and I&rsquo;ll probably gofor it when I start a third book using this approach.</p>
<p>I&rsquo;d like to be able to define something like a standard <code>book/</code> dir that wouldbe to a given text what <code>.git/</code> is to the working copy of a repo.  I supposeyou wouldn&rsquo;t need much.</p>
<pre><code>book/  authors  title  description  license  toc</code></pre>
<p><code>toc</code> would just be an ordered list of files to include as &ldquo;chapters&rdquo; from theroot of the project.  You&rsquo;d just organize it however you liked and optionallyuse commands like</p>
<pre><code>book add chapter/index.md after other_chapter/index.mdbook move chapter/index.md before other_chapter/index.md</code></pre>
<p>to manage it, though really a text editor should be enough. (Maybe I&rsquo;moverthinking this.  Maybe there should just be a directory full of chapterssorted numerically on leading digits or something, but I&rsquo;ve liked being able toreorder things in an explicit list.)</p>
<p>Before long I might well add handling for some</p>
<p>I should add a feature to Display.pm for outputting all of its contentstatically.</p>

</article>


<article>
<h1><a name=Monday-January-12 href=#Monday-January-12>#</a> Monday, January 12</h1>
<h2><a name=Monday-January-12-Debian-packaging href=#Monday-January-12-Debian-packaging>#</a> Debian packaging</h2>
<p>A lot of time today withthe <a href="https://www.debian.org/doc/manuals/maint-guide/">Debian New Maintainer&rsquo;s Guide</a>and google for a project that needs some simple packages.</p>
<p>This is one of those things where the simple cases are simple and then it&rsquo;seasy to get lost in a thicket of overlapping mechanisms and terminology.</p>
<p>Thought for providers of technical HOWTOs:</p>
<p>If you&rsquo;re describing the cumulative assembly of a file structure, provide acopy (repository, tarball, whatever) of that file structure.</p>
<p>(I should probably take this notion to heart.)</p>
<p>Things to remember:</p>
<ul><li><a href="http://man.he.net/man1/fakeroot">http://man.he.net/man1/fakeroot</a></li></ul>

<h2><a name=Monday-January-12-MS-DOS-AGT href=#Monday-January-12-MS-DOS-AGT>#</a> MS-DOS / AGT</h2>
<p>So I was scrolling through archive.org&rsquo;s newly-shiny MS-DOS archive (with thecrazy in-browser DOSBOX emulation), trying to think of what to look for.</p>
<p>I found some old friends:</p>
<ul><li><a href="https://archive.org/details/msdos__1CRYSTL_shareware"><em>Crystal Caves</em></a></li><li><a href="https://archive.org/details/msdos_Commander_Keen_1_-_Marooned_on_Mars_1990"><em>Commander Keen</em></a></li><li><a href="https://archive.org/details/msdos_Heretic_-_Shadow_of_the_Serpent_Riders_1996"><em>Heretic</em></a> &mdash; still a pretty solid game and maybe my favorite iteration of the Doom Engine</li><li><a href="https://archive.org/details/msdos_Rise_of_the_Triad_-_The_Hunt_Begins_Deluxe_Edition_1995"><em>Rise of the Triads</em></a> &mdash; there is absolutely <em>no way</em> that ROTT actuallylooked as bad as this emulation at the time on baseline hardware, but we&rsquo;ll letthat slide &mdash; the graphics may have been better than they show here, but itwas the Duke Nukem property of its moment, which is to say ultimately aregressive and not-very-consequential signpost on the way to laterdevelopments</li></ul>

<p>And then I got to thinking about the Adventure Game Toolkit, which was thissort of declarative, not-really-programmable interpreter for simple adventuregames.  The way I remember it, you wrote static descriptions of rooms, objects,and characters.  It was a limited system, and the command interpreter waspretty terrible, but it was also a lot more approachable than things like TADSfor people who didn&rsquo;t really know how to program anyway.  (Like me at the time.)</p>
<p>I&rsquo;d like to get AGT running on squiggle.city, just because.  It turns outthere&rsquo;s a <a href="http://www.ifarchive.org/indexes/if-archiveXprogrammingXagtXagility.html">portable interpreter called AGiliTY</a>, although maybe notone that&rsquo;s well packaged.  I&rsquo;ll probably explore this more.</p>

</article>


<article>
<h1><a name=Tuesday-January-13 href=#Tuesday-January-13>#</a> Tuesday, January 13</h1>
<h2><a name=Tuesday-January-13-rtd-bus-schedules-transit-data href=#Tuesday-January-13-rtd-bus-schedules-transit-data>#</a> rtd / bus schedules / transit data</h2>
<p>I&rsquo;m taking the bus today, so I got to thinking about bus schedules.  I useGoogle Calendar a little bit (out of habit and convenience more than anyparticular love), and I was thinking &ldquo;why doesn&rsquo;t my calendar just know thetimes of transit routes I use?&rdquo;</p>
<p>I thought maybe there&rsquo;d be, say, iCal (CalDAV? What is actually the thing?)data somewhere for a given RTD schedule, or failing that, maybe JSON or TSV orsomething.  A cursory search doesn&rsquo;t turn up much, but I did find these:</p>
<ul><li><a href="http://www.rtd-denver.com/Developer.shtml">http://www.rtd-denver.com/Developer.shtml</a></li><li><a href="https://developers.google.com/transit/gtfs/reference?csw=1">https://developers.google.com/transit/gtfs/reference?csw=1</a></li><li><a href="http://www.rtd-denver.com/GoogleFeeder/">http://www.rtd-denver.com/GoogleFeeder/</a></li><li><a href="http://www.rtd-denver.com/GoogleFeeder/google_transit_Jan15_Runboard.zip">http://www.rtd-denver.com/GoogleFeeder/google_transit_Jan15_Runboard.zip</a></li></ul>

<p>I grabbed that last one.</p>
<pre><code>brennen@desiderata 16:16:43 /home/brennen ★  mkdir rtd &amp;&amp; mv google_transit_Jan15_Runboard.zip rtd brennen@desiderata 16:16:51 /home/brennen ★  cd rtdbrennen@desiderata 16:16:53 /home/brennen/rtd ★  unzip google_transit_Jan15_Runboard.zip Archive:  google_transit_Jan15_Runboard.zip  inflating: calendar.txt              inflating: calendar_dates.txt        inflating: agency.txt                inflating: shapes.txt                inflating: stop_times.txt            inflating: trips.txt                 inflating: stops.txt                 inflating: routes.txt              </code></pre>
<p>Ok, so this is pretty minimalist CSV stuff from the look of most of it.</p>
<pre><code>brennen@desiderata 16:22:12 /home/brennen/rtd ★  grep Lyons stops.txt20921,Lyons PnR,Vehicles Travelling East, 40.223979,-105.270174,,,0</code></pre>
<p>So it looks like stops have an individual id?</p>
<pre><code>brennen@desiderata 16:24:41 /home/brennen/rtd ★  grep '20921' ./*.txt | wc -l87</code></pre>
<p>A lot of this is noise, but:</p>
<pre><code>brennen@desiderata 16:26:23 /home/brennen/rtd ★  grep 20921 ./stop_times.txt 8711507,12:52:00,12:52:00,20921,43,,1,0,8711508,11:32:00,11:32:00,20921,43,,1,0,8711509,07:55:00,07:55:00,20921,43,,1,0,8711512,16:41:00,16:41:00,20921,43,,1,0,8711519,05:37:00,05:37:00,20921,3,,0,1,8711517,16:47:00,16:47:00,20921,1,,0,1,8711511,17:58:00,17:58:00,20921,43,,1,0,8711514,13:02:00,13:02:00,20921,1,,0,1,8711516,07:59:00,07:59:00,20921,1,,0,1,8711515,11:42:00,11:42:00,20921,1,,0,1,8711510,19:10:00,19:10:00,20921,43,,1,0,8711513,18:05:00,18:05:00,20921,1,,0,1,8711518,06:47:00,06:47:00,20921,1,,0,1,brennen@desiderata 16:26:57 /home/brennen/rtd ★  head -1 stop_times.txttrip_id,arrival_time,departure_time,stop_id,stop_sequence,stop_headsign,pickup_type,drop_off_type,shape_dist_traveled</code></pre>
<p>So:</p>
<pre><code>brennen@desiderata 16:41:47 /home/brennen/code/rtd-tools (master) ★  grep ',20921,' ./stop_times.txt | cut -d, -f1,3 | sort -n8711507,12:52:008711508,11:32:008711509,07:55:008711510,19:10:008711511,17:58:008711512,16:41:008711513,18:05:008711514,13:02:008711515,11:42:008711516,07:59:008711517,16:47:008711518,06:47:008711519,05:37:00</code></pre>
<p>That first number is a <code>trip_id</code>, the second one departure time.  Tripsare provided in <code>trips.txt</code>:</p>
<pre><code>brennen@desiderata 16:54:56 /home/brennen/code/rtd-tools (master) ★  head -2 trips.txtroute_id,service_id,trip_id,trip_headsign,direction_id,block_id,shape_id0,SA,8690507,Union Station,0,   0  2,793219</code></pre>
<p>I don&rsquo;t usually use <code>join</code> very much, but this seems like a logical place forit.  It turns out that <code>join</code> wants its input sorted on the join field, so I dothis:</p>
<pre><code>brennen@desiderata 16:54:38 /home/brennen/code/rtd-tools (master) ★  sort -t, -k1 stop_times.txt &gt; stop_times.sorted.txtbrennen@desiderata 16:54:38 /home/brennen/code/rtd-tools (master) ★  sort -t, -k3 trips.txt &gt; trips.sorted.txt </code></pre>
<p>And then:</p>
<pre><code>brennen@desiderata 16:51:07 /home/brennen/code/rtd-tools (master) ★  join -t, -1 1 -2 3 ./stop_times.sorted.txt ./trips.sorted.txt | grep 20921,Y,WK,Lyons PnR,0,   Y 16,79481043,,1,0,,Y,WK,Lyons PnR,0,   Y 16,79481043,,1,0,,Y,WK,Lyons PnR,0,   Y 15,79481043,,1,0,,Y,WK,Lyons PnR,0,   Y 41,79480943,,1,0,,Y,WK,Lyons PnR,0,   Y 41,79481043,,1,0,,Y,WK,Lyons PnR,0,   Y 41,79481043,,1,0,,Y,WK,Boulder Transit Center,1,   Y 41,794814,Y,WK,Boulder Transit Center,1,   Y 16,794812,Y,WK,Boulder Transit Center,1,   Y 16,794814,Y,WK,Boulder Transit Center,1,   Y 15,794812,Y,WK,Boulder Transit Center,1,   Y 41,794813,Y,WK,Boulder Transit Center,1,   Y 15,794813,Y,WK,Boulder Transit Center,1, 206  1,794816</code></pre>
<p>Ok, waitasec. What the fuck is going on here?  The string <code>20921</code> appearsnowhere in these lines.  It takes me too long to figure out that thetext files have CRLF line-endings and this is messing with something inthe chain (probably just output from <code>grep</code>, since it&rsquo;s obviouslyfinding the string).  So:</p>
<pre><code>brennen@desiderata 16:59:35 /home/brennen/code/rtd-tools (master) ★  dos2unix *.sorted.txt    dos2unix: converting file stop_times.sorted.txt to Unix format ...dos2unix: converting file trips.sorted.txt to Unix format ...</code></pre>
<p>Why does <code>dos2unix</code> operate in-place on files instead of printing to STDOUT?It beats me, but I sure am glad I didn&rsquo;t run it on anything especiallybreakable.  It <em>does</em> do what you&rsquo;d expect when piped to, anyway, which isprobably what I should have done.</p>
<p>So this seems to work:</p>
<pre><code>brennen@desiderata 17:04:45 /home/brennen/code/rtd-tools (master) ★  join -t, -1 1 -2 3 ./stop_times.sorted.txt ./trips.sorted.txt | grep 209218711507,12:52:00,12:52:00,20921,43,,1,0,,Y,WK,Lyons PnR,0,   Y 16,7948108711508,11:32:00,11:32:00,20921,43,,1,0,,Y,WK,Lyons PnR,0,   Y 16,7948108711509,07:55:00,07:55:00,20921,43,,1,0,,Y,WK,Lyons PnR,0,   Y 15,7948108711510,19:10:00,19:10:00,20921,43,,1,0,,Y,WK,Lyons PnR,0,   Y 41,7948098711511,17:58:00,17:58:00,20921,43,,1,0,,Y,WK,Lyons PnR,0,   Y 41,7948108711512,16:41:00,16:41:00,20921,43,,1,0,,Y,WK,Lyons PnR,0,   Y 41,7948108711513,18:05:00,18:05:00,20921,1,,0,1,,Y,WK,Boulder Transit Center,1,   Y 41,7948148711514,13:02:00,13:02:00,20921,1,,0,1,,Y,WK,Boulder Transit Center,1,   Y 16,7948128711515,11:42:00,11:42:00,20921,1,,0,1,,Y,WK,Boulder Transit Center,1,   Y 16,7948148711516,07:59:00,07:59:00,20921,1,,0,1,,Y,WK,Boulder Transit Center,1,   Y 15,7948128711517,16:47:00,16:47:00,20921,1,,0,1,,Y,WK,Boulder Transit Center,1,   Y 41,7948138711518,06:47:00,06:47:00,20921,1,,0,1,,Y,WK,Boulder Transit Center,1,   Y 15,7948138711519,05:37:00,05:37:00,20921,3,,0,1,,Y,WK,Boulder Transit Center,1, 206  1,794816</code></pre>
<p>Which seems kind of right for the <a href="http://www3.rtd-denver.com/schedules/getSchedule.action?runboardId=151&amp;routeId=Y&amp;routeType=12&amp;direction=S-Bound&amp;serviceType=3">South</a> &amp;<a href="http://www3.rtd-denver.com/schedules/getSchedule.action?runboardId=151&amp;routeId=Y&amp;routeType=12&amp;direction=N-Bound&amp;serviceType=3">Northbound</a> schedules, but they&rsquo;re weirdly intermingled.  I thinkthis pulls departure time and a <code>direction_id</code> field:</p>
<pre><code>brennen@desiderata 17:15:12 /home/brennen/code/rtd-tools (master) ★  join -t, -1 1 -2 3 ./stop_times.sorted.txt ./trips.sorted.txt | grep 20921 | cut -d, -f3,13 | sort -n05:37:00,106:47:00,107:55:00,007:59:00,111:32:00,011:42:00,112:52:00,013:02:00,116:41:00,016:47:00,117:58:00,018:05:00,119:10:00,0</code></pre>
<p>So southbound, I guess:</p>
<pre><code>brennen@desiderata 17:15:59 /home/brennen/code/rtd-tools (master) ★  join -t, -1 1 -2 3 ./stop_times.sorted.txt ./trips.sorted.txt | grep 20921 | cut -d, -f3,13 | grep ',1' | sort -n05:37:00,106:47:00,107:59:00,111:42:00,113:02:00,116:47:00,118:05:00,1</code></pre>
<p>This should probably be where I think oh, right, this is a Google spec - maybethere&rsquo;s <a href="https://github.com/google/transitfeed">already some tooling</a>.  Failingthat, slurping them into SQLite or something would be a lot less painful.  Orat least using csvkit.</p>

</article>


<article>
<h1><a name=Wednesday-January-14-2015 href=#Wednesday-January-14-2015>#</a> Wednesday, January 14, 2015</h1>
<p>On making a web page remind me of a quality I never fully appreciated inHyperCard.</p>
<p>So I generally am totally ok with scrolling on web pages.  I think infact it&rsquo;s a major advantage of the form.</p>
<p>Then again, I just got to indulging a few minutes of thinking aboutHyperCard, and I think that this time rather than read the same oldarticles about its ultimate doom over and over again, maybe I should dosomething by way of recreating part of it that was different from theweb in general.</p>
<p>The web has plenty of stupid carousels and stuff, but despite their example I&rsquo;mcurious whether HyperCard&rsquo;s stack model could still hold up as an idea.  I wasnever sure whether it was the important thing or not.  It was so obviously andalmost clumsily a <em>metaphor</em>.  (A skeuomorphism which I have never actuallyseen anyone bag on when they are playing that game, perhaps because DesignerIdeologues know there&rsquo;s not much percentage in talking shit about HyperCard.)</p>
<p>Here is some JavaScript to start:</p>
<pre><code>$('article').each(function (i, a) {  $(a).hide();});$('article').first().show();</code></pre>
<p>I&rsquo;ll spare you the usual slow-composition narrative of where I go from here,and jump straight to my eventual <a href="https://github.com/brennen/tildebrennen/commit/560826a9884dae47998843dcf4917266b3344fec">first-pass solution</a>.</p>
<p>(Ok, actually I just repurposed a terrible thing I did for some slides a whileback, after recreating about 75% without remembering that I had already writtenthe same code within the last couple of months.  It&rsquo;s amazing how often thathappens, or I guess it would be amazing if my short term memory weren&rsquo;t sothoroughly scrambled from all the evil living I do.)</p>

</article>


<article>
<h1><a name=Friday-January-16 href=#Friday-January-16>#</a> Friday, January 16</h1>
<p><a href="http://www.raspberrypi.org/documentation/configuration/wireless/wireless-cli.md">Wireless configuration under Raspbian</a>.</p>

</article>


<article>
<h1><a name=Tuesday-January-20 href=#Tuesday-January-20>#</a> Tuesday, January 20</h1>

<p>I wanted to figure out where I used a library in existing code.</p>
<p>This is what I wound up doing in zsh:</p>
<pre><code>brennen@exuberance 11:48:07 /home/brennen/code $  for foo in `ls -f`; do; if [[ -d $foo/.git ]]; then cd $foo; echo '--' $foo '--'; git grep 'IPC::System::Simple'; cd ~/code; fi; done-- thcipriani-dotfiles ---- sfe-sysadmin ---- pi_bootstrap ---- bpb-kit ---- batchpcb ---- according-to-pete ---- meatbags ---- sfe-paleo ---- instruct ---- sfe-openstack ---- YouTube_Captions ---- batchpcb_rails ---- userland-book --slides/render.pl:use IPC::System::Simple qw(capturex);-- sfe-custom-queries ---- brennen-sparklib-fork ---- tilde.club ---- display ---- sfe-chef ---- xrectsel ---- git-feed --git-feed:use IPC::System::Simple qw(capturex);sample_feed.xml: use IPC::System::Simple qw(capturex);sample_feed.xml:+use IPC::System::Simple qw(capturex);-- reddit ---- rtd-tools ---- sparkfun ---- mru --</code></pre>
<p>Lame-ish, but I&rsquo;m perpetually forgetting shell loop and conditional syntax, soit seems worth making a note of.</p>

</article>


<article>
<h1><a name=Thursday-January-22 href=#Thursday-January-22>#</a> Thursday, January 22</h1>

<h2><a name=Thursday-January-22-deleting-files-from-git-history href=#Thursday-January-22-deleting-files-from-git-history>#</a> deleting files from git history</h2>
<p>Working on a project where we included some built files that took up a bunch ofspace, and decided we should get rid of those.  The git repository isn&rsquo;t publicyet and is only shared by a handful of users, so it seemed worth thinking aboutrewriting the history a bit.</p>
<p>There&rsquo;s reasonably good documentation for this in the usual places if you look,but I ran into some trouble.</p>
<p>First, what seemed to work:  David Underhill has a <a href="http://dound.com/2009/04/git-forever-remove-files-or-folders-from-history/">good short script</a> fromback in 2009 for using <code>git filter-branch</code> to eliminate particular files fromhistory:</p>
<blockquote><p>I recently had a need to rewrite a git repository’s history. This isn’tgenerally a very good idea, though it is useful if your repository containsfiles it should not (such as unneeded large binary files or copyrightedmaterial). I also am using it because I had a branch where I only wanted tomerge a subset of files back into master (though there are probably betterways of doing this). Anyway, it is not very hard to rewrite history thanks tothe excellent git-filter-branch tool which comes with git.</p></blockquote>
<p>I&rsquo;ll reproduce the script here, in the not-unlikely event that his writeup goesaway:</p>
<pre><code>#!/bin/bashset -o errexit
# Author: David Underhill# Script to permanently delete files/folders from your git repository.  To use # it, cd to your repository's root and then run the script with a list of paths# you want to delete, e.g., git-delete-history path1 path2
if [ $# -eq 0 ]; then    exit 0fi
# make sure we're at the root of git repoif [ ! -d .git ]; then    echo "Error: must run this script from the root of a git repository"    exit 1fi
# remove all paths passed as arguments from the history of the repofiles=$@git filter-branch --index-filter "git rm -rf --cached --ignore-unmatch $files" HEAD
# remove the temporary history git-filter-branch otherwise leaves behind for a long timerm -rf .git/refs/original/ &amp;&amp; git reflog expire --all &amp;&amp;  git gc --aggressive --prune</code></pre>
<p>A big thank you to Mr. Underhill for documenting this one. <code>filter-branch</code>seems really powerful, and not as brain-hurting as some things in git land.The <a href="http://git-scm.com/docs/git-filter-branch">docs</a> are currently pretty good, and worth a read if you&rsquo;re trying tosolve this problem.</p>
<blockquote><p>Lets you rewrite Git revision history by rewriting the branches mentioned inthe <rev-list options>, applying custom filters on each revision. Thosefilters can modify each tree (e.g. removing a file or running a perl rewriteon all files) or information about each commit. Otherwise, all information(including original commit times or merge information) will be preserved.</p></blockquote>
<p>After this, things got muddier.  The script seemed to work fine, and afterrunning it I was able to see all the history I expected, minus some troublesomefiles.  (A version with <code>--prune-empty</code> added to the <code>git filter-branch</code>invocation got rid of some empty commits.)  But then:</p>
<pre><code>brennen@exuberance 20:05:00 /home/brennen/code $  du -hs pi_bootstrap 218M    pi_bootstrapbrennen@exuberance 20:05:33 /home/brennen/code $  du -hs experiment199M    experiment</code></pre>
<p>That second repo is a clone of the original with the script run against it.Why is it only tens of megabytes smaller, when minus the big binaries I zapped,it should come in somewhere under 10 megs?</p>
<p>I will spare you, dear reader, the contortions I went through arriving at asolution for this, partially because I don&rsquo;t have the energy left toreconstruct them from the tattered history of my googling over the last fewhours.  What I figured out was that for some reason, a bunch of blobs werepersisting in a pack file, despite not being referenced by any commits, and nomatter what I couldn&rsquo;t get <code>git gc</code> or <code>git repack</code> to zap them.</p>
<p>I more or less got this far with commands like:</p>
<pre><code>brennen@exuberance 20:49:10 /home/brennen/code/experiment2/.git (master) $  git count-objects -vcount: 0size: 0in-pack: 2886packs: 1size-pack: 202102prune-packable: 0garbage: 0size-garbage: 0</code></pre>
<p>And:</p>
<pre><code>git verify-pack -v ./objects/pack/pack-b79fc6e30a547433df5c6a0c6212672c5e5aec5f &gt; ~/what_the_fuck</code></pre>
<p>&hellip;which gives a list of all the stuff in a pack file, includingsuper-not-human-readable sizes that you can sort on, and many permutations ofthings like:</p>
<pre><code>brennen@exuberance 20:49:12 /home/brennen/code/experiment2/.git (master) $  git log --pretty=oneline | cut -f1 -d' ' | xargs -L1 git cat-file -s | sort -nr | head589364363348341331325325322320</code></pre>
<p>&hellip;where <code>cat-file</code> is a bit of a Swiss army knife for looking at objects, with<code>-s</code> meaning &ldquo;tell me a size&rdquo;.</p>
<p>(An aside:  If you are writing software that outputs a size in bytes, blocks,etc., and you do not provide a &ldquo;human readable&rdquo; option to display this incomprehensible units, the innumerate among us quietly hate your guts.  This isperhaps unjust of us, but I&rsquo;m just trying to communicate my experience here.)</p>
<p>And finally, <a href="https://stackoverflow.com/questions/223678/which-commit-has-this-blob/223890#223890">Aristotle Pagaltzis&rsquo;s script</a> for figuring out which commithas a given blob (the answer is <em>fucking none of them</em>, in my case):</p>
<pre><code>#!/bin/shobj_name="$1"shiftgit log "$@" --pretty=format:'%T %h %s' \| while read tree commit subject ; do    if git ls-tree -r $tree | grep -q "$obj_name" ; then        echo $commit "$subject"    fidone</code></pre>
<p>Also somewhere in there I learned how to use <a href="http://git-scm.com/docs/git-bisect"><code>git bisect</code></a> (which isreally cool and likely something I will use again) and went through and madeentirely certain there was nothing in the history with a bunch of big filesin it.</p>
<p>So eventually I got to thinking ok, there&rsquo;s something here that is keepingthese objects from getting expired or pruned or garbage collected or whatever,so how about doing a clone that just copies the stuff in the commits that stillexist at this point.  Which brings us to:</p>
<pre><code>brennen@exuberance 19:03:08 /home/brennen/code/experiment2 (master) $  git help clonebrennen@exuberance 19:06:52 /home/brennen/code/experiment2 (master) $  cd ..brennen@exuberance 19:06:55 /home/brennen/code $  git clone --no-local ./experiment2 ./experiment2_no_localCloning into './experiment2_no_local'...remote: Counting objects: 2874, done.remote: Compressing objects: 100% (1611/1611), done.remote: Total 2874 (delta 938), reused 2869 (delta 936)Receiving objects: 100% (2874/2874), 131.21 MiB | 37.48 MiB/s, done.Resolving deltas: 100% (938/938), done.Checking connectivity... done.brennen@exuberance 19:07:15 /home/brennen/code $  du -hs ./experiment2_no_local133M    ./experiment2_no_localbrennen@exuberance 19:07:20 /home/brennen/code $  git help clonebrennen@exuberance 19:08:34 /home/brennen/code $  git clone --no-local --single-branch ./experiment2 ./experiment2_no_local_single_branchCloning into './experiment2_no_local_single_branch'...remote: Counting objects: 1555, done.remote: Compressing objects: 100% (936/936), done.remote: Total 1555 (delta 511), reused 1377 (delta 400)Receiving objects: 100% (1555/1555), 1.63 MiB | 0 bytes/s, done.Resolving deltas: 100% (511/511), done.Checking connectivity... done.brennen@exuberance 19:08:47 /home/brennen/code $  du -hs ./experiment2_no_local_single_branch3.0M    ./experiment2_no_local_single_branch</code></pre>
<p>What&rsquo;s going on here?  <a href="http://git-scm.com/docs/git-clone">Well</a>, <code>git clone --no-local</code>:</p>
<pre><code>--local-l
    When the repository to clone from is on a local machine, this flag    bypasses the normal "Git aware" transport mechanism and clones the    repository by making a copy of HEAD and everything under objects and    refs directories. The files under .git/objects/ directory are    hardlinked to save space when possible.
    If the repository is specified as a local path (e.g., /path/to/repo),    this is the default, and --local is essentially a no-op. If the    repository is specified as a URL, then this flag is ignored (and we    never use the local optimizations). Specifying --no-local will override    the default when /path/to/repo is given, using the regular Git    transport instead.</code></pre>
<p>And <code>--single-branch</code>:</p>
<pre><code>--[no-]single-branch
    Clone only the history leading to the tip of a single branch, either    specified by the --branch option or the primary branch remote’s HEAD    points at. When creating a shallow clone with the --depth option, this    is the default, unless --no-single-branch is given to fetch the    histories near the tips of all branches. Further fetches into the    resulting repository will only update the remote-tracking branch for    the branch this option was used for the initial cloning. If the HEAD at    the remote did not point at any branch when --single-branch clone was    made, no remote-tracking branch is created.</code></pre>
<p>I have no idea why <code>--no-local</code> by itself reduced the size but didn&rsquo;t really dothe job.</p>
<p>It&rsquo;s possible the lingering blobs would have been garbage collected<em>eventually</em>, and at any rate it seems likely that in pushing them to a remoterepository I would have bypassed whatever lazy local file copy operation wascausing everything to persist on cloning, thus rendering all thishead-scratching entirely pointless, but then who knows.  At least I understandgit file structure a little better than I did before.</p>
<p>For good measure, I just remembered how old much of the software on thismachine is, and I feel like kind of an ass:</p>
<pre><code>brennen@exuberance 21:20:50 /home/brennen/code $  git --versiongit version 1.9.1</code></pre>
<p>This is totally an old release.  If there&rsquo;s a bug here, maybe it&rsquo;s fixed bynow.  I will not venture a strong opinion as to whether there is a bug.  Maybethis is entirely expected behavior.  It is time to drink a beer.</p>
<h2><a name=Thursday-January-22-postscript-on-finding-bugs href=#Thursday-January-22-postscript-on-finding-bugs>#</a> postscript:  on finding bugs</h2>
<p>The first thing you learn, by way of considerable personal frustration andembarrassment, goes something like this:</p>
<blockquote><p>Q: My stuff isn&rsquo;t working.  I think there is probably a bug in this matureand widely-used (programming language | library | utility software).</p>
<p>A: Shut up shut up shut up <em>shut up</em> there is not a bug.  Now go and figureout what is wrong with your code.</p></blockquote>
<p>The second thing goes something like this:</p>
<blockquote><p>Oh.  I guess that&rsquo;s actually a bug.</p></blockquote>
<p>Which is to say:  I have learned that I&rsquo;m probably wrong, but sometimes I&rsquo;malso wrong about being wrong.</p>

</article>


<article>
<h1><a name=Sunday-January-25-2015 href=#Sunday-January-25-2015>#</a> Sunday, January 25, 2015</h1>
<h2><a name=Sunday-January-25-2015-background-colors-for-tmux href=#Sunday-January-25-2015-background-colors-for-tmux>#</a> background colors for tmux</h2>
<p>I&rsquo;m logged into too many machines.  I make an effort to have prompt colors differbetween hosts, but tmux is the same everywhere.</p>
<p>You can do this sort of thing:</p>
<pre><code>brennen@exuberance 11:54:43 /home/brennen/code $  cat ~/.tmux.conf # Set window notificationssetw -g monitor-activity onset -g visual-activity onset -g status-bg blueset -g status-fg white</code></pre>
<p>&hellip;where <code>status-bg</code> and <code>status-fg</code> are colors for the status bar.</p>
<p>It seems like there may be ways to conditionalize this, but at this point I&rsquo;mtempted to just pull some simple templating system into my <a href="https://github.com/brennen/bpb-kit">dotfilestuff</a> and generate a subset of config files on a per-host basis.</p>

</article>


<article>
<h1><a name=Tuesday-January-27 href=#Tuesday-January-27>#</a> Tuesday, January 27</h1>

<h2><a name=Tuesday-January-27-what-version-of-what-linux-distribution-is-this href=#Tuesday-January-27-what-version-of-what-linux-distribution-is-this>#</a> what version of what linux distribution is this?</h2>
<p>Some luck <em>may</em> be had with one or more of:</p>
<pre><code>root@beaglebone:~# uname -aLinux beaglebone 3.8.13-bone47 #1 SMP Fri Apr 11 01:36:09 UTC 2014 armv7l GNU/Linux
root@beaglebone:~# lsb_release -aNo LSB modules are available.Distributor ID: DebianDescription:    Debian GNU/Linux 7.8 (wheezy)Release:    7.8Codename:   wheezy
root@beaglebone:~# cat /etc/debian_version 7.8
root@beaglebone:~# cat /etc/dogtagBeagleBoard.org BeagleBone Debian Image 2014-04-23
root@beaglebone:~# cat /etc/os-release PRETTY_NAME="Debian GNU/Linux 7 (wheezy)"NAME="Debian GNU/Linux"VERSION_ID="7"VERSION="7 (wheezy)"ID=debianANSI_COLOR="1;31"HOME_URL="http://www.debian.org/"SUPPORT_URL="http://www.debian.org/support/"BUG_REPORT_URL="http://bugs.debian.org/"</code></pre>
<h2><a name=Tuesday-January-27-armhf href=#Tuesday-January-27-armhf>#</a> armhf</h2>
<p><a href="https://blogs.oracle.com/jtc/entry/is_it_armhf_or_armel">Is it armhf or armel?</a>:</p>
<blockquote><p>During diagnosis, the question becomes, how can I determine whether my Linuxdistribution is based on armel or armhf?  Turns out this is not asstraightforward as one might think.  Aside from experience and anecdotalevidence, one possible way to ascertain whether you&rsquo;re running on armel orarmhf is to run the following obscure command:</p>
<pre><code>$ readelf -A /proc/self/exe | grep Tag_ABI_VFP_args</code></pre>
<p>If the Tag_ABI_VFP_args tag is found, then you&rsquo;re running on an armhf system.If nothing is returned, then it&rsquo;s armel.  To show you an example, here&rsquo;s whathappens on a Raspberry Pi running the Raspbian distribution:</p>
<pre><code>pi@raspberrypi:~$ readelf -A /proc/self/exe | grep Tag_ABI_VFP_argsTag_ABI_VFP_args: VFP registers</code></pre>
<p>This indicates an armhf distro, which in fact is what Raspbian is.  On theoriginal, soft-float Debian Wheezy distribution, here&rsquo;s what happens:</p>
<pre><code>pi@raspberrypi:~$ readelf -A /proc/self/exe | grep Tag_ABI_VFP_args</code></pre>
<p>Nothing returned indicates that this is indeed armel.</p></blockquote>
<p>On a recent-ish Beaglebone Black:</p>
<pre><code>root@beaglebone:~# readelf -A /proc/self/exe | grep Tag_ABI_VFP_args  Tag_ABI_VFP_args: VFP registers</code></pre>

</article>


<article>
<h1><a name=Wednesday-January-28 href=#Wednesday-January-28>#</a> Wednesday, January 28</h1>

<h2><a name=Wednesday-January-28-on-replicating-process href=#Wednesday-January-28-on-replicating-process>#</a> on replicating process</h2>
<p>Ok, so here we are.  It&rsquo;s 2015.  The gold standard for explaining how yousolved a technical problem to the internet at large is a blog post with thingsyou can copy and paste or maybe some pictures.</p>
<p>If you&rsquo;re really lucky, someone actually has reusable a public repository ofsome kind.  If you&rsquo;re <em>really</em> lucky, their code works, and if all the godsare smiling on you at once, their code is <em>documented</em>.</p>
<p>It seems to me that we can do better than this.  We possess a great many of theright <em>tools</em> to do better than this, at least for a lot of common problems.What does it take to make a given workflow both repeatable and legible topeople without the context we have for a given thing (including ourselves)?Writing about it is surely desirable, but how do you approach a problem sothat, instead of being scattered across your short term memory and a dozenvolatile buffers, your work becomes a kind of document unto itself?</p>
<p>This is the (beautiful) root of what version control does, after all:  Itrenders a normally-invisible process legible, and in its newfound legibility,at least a little susceptible to transmission and reuse.</p>
<p>What do I know works well for transmitting process and discovery, as far as itgoes?</p>
<ul><li>version control (so really git, which is severally horrible but alsobrilliant and wins anyway)</li><li>Makefiles (except that I don&rsquo;t understand make at <em>all</em>)</li><li>shell scripts (except that shell programming is an utter nightmare)</li><li>Debian packages (which are more or less compounded of the above, andmoderately torturous to build)</li><li>IRC, if you keep logs, because it&rsquo;s amazing how much knowledge is most purelyconveyed in the medium of internet chat</li><li>Stackoverflow &amp; friends (I hate this, but there it is, it&rsquo;s a fact, we have todeal with it no matter how much we hate process jockies, just like Wikipedia)</li><li>screenshots and screencasts (a pain to make, all-too-often free of context, andyet)</li></ul>

<p>Here are some things that I think are often terrible at this stuff despitetheir ubiquity:</p>
<ul><li>mailing lists (so bad, so <em>routinely pathological</em>, so utterly necessary toeverything)</li><li>web forums like phpBB and stuff (so bad, so ubiquitous, so going to show upin your google results with the hint you desperately needed, but only if you&rsquo;resmart enough to parse it out of the spew)</li></ul>

<p>Here&rsquo;s one problem:  There are a lot of relatively painless once you know themtools, like &ldquo;let&rsquo;s just make this a dvcs repo because it&rsquo;s basically free&rdquo;,that if you know they exist and you really want to avoid future suffering youjust get in the habit of using by default.  But most people don&rsquo;t know thesetools exist, or that they&rsquo;re <em>generally applicable tools</em> and not justspecialist things you might use for the one important thing at your job becausesomebody said you should.</p>
<h2><a name=Wednesday-January-28-what-makes-programming-hard href=#Wednesday-January-28-what-makes-programming-hard>#</a> what makes programming hard?</h2>
<ol><li>Most of the existing programs.</li><li>Most of the existing programming languages.</li><li>Other programmers.</li><li>Human thought is brutally constrained in understanding complex systems.</li><li>Ok you wrote some programs anyway now GOTO 0.</li></ol>

<h2><a name=Wednesday-January-28-debian-packaging-again href=#Wednesday-January-28-debian-packaging-again>#</a> debian packaging again</h2>
<p>I&rsquo;m starting <a href="https://www.debian.org/doc/manuals/maint-guide/">here</a> again.</p>
<ul><li><a href="https://wiki.debian.org/IntroDebianPackaging">https://wiki.debian.org/IntroDebianPackaging</a></li><li><a href="https://www.debian.org/doc/manuals/packaging-tutorial/packaging-tutorial.en.pdf">https://www.debian.org/doc/manuals/packaging-tutorial/packaging-tutorial.en.pdf</a>(actually more helpful than anything else I&rsquo;ve found so far)</li></ul>

<h2><a name=Wednesday-January-28-vagrant href=#Wednesday-January-28-vagrant>#</a> vagrant</h2>
<p>Vagrant is a thing for quickly provisioning / tearing down / connecting tovirtual machines.  It wraps VirtualBox, among other providers.  I think thebasic appeal is that you get cheap, more-or-less disposable environments with acouple of commands, and there&rsquo;s scaffolding for simple scripts to configure abox when it&rsquo;s brought up, or share directories with the host filesystem.  It&rsquo;sreally lightweight to try out.</p>
<p>Go to the <a href="http://www.vagrantup.com/downloads">downloads page</a> and install fromthere.  I used the 64 bit Ubuntu .deb.</p>
<pre><code>$ sudo apt-get install virtualbox$ sudo dpkg -i vagrant_1.7.2_x86_64.deb$ mkdir vagrant_test$ cd vagrant_test$ vagrant init hashicorp/precise32$ vagrant up$ vagrant ssh</code></pre>
<p>This stuff takes a while on the first run through, but is generally reallyslick.  <code>hashicorp/precise32</code> is more or less just a preconfigured image pulledfrom a central repository.</p>
<p>Their <a href="http://docs.vagrantup.com/v2/getting-started/index.html">Getting Started</a> is prettydecent.</p>
<p>People around me have been enthusing about this kind of thing for ages, but Ihaven&rsquo;t really gotten around to figuring out why I should care until recently.I will probably be using this tool for a lot of development tasks.</p>
<p>Other notes:</p>
<ul><li>stackoverflow: <a href="https://stackoverflow.com/questions/17117063/how-can-i-create-a-vm-in-vagrant-with-virtualbox-with-two-cpus">How can I create a VM in vagrant with virtualbox with two cpus?</a></li><li><a href="https://tylercipriani.com/2014/05/25/lightweight-portable-vagrant-docker.html">Development Environments with Vagrant, Docker, and Supervisord</a></li></ul>


</article>


<article>
<h1><a name=Thursday-January-29 href=#Thursday-January-29>#</a> Thursday, January 29</h1>

<h2><a name=Thursday-January-29-raspberry-pi-kernels href=#Thursday-January-29-raspberry-pi-kernels>#</a> raspberry pi kernels</h2>
<ul><li><a href="http://elinux.org/Raspberry_Pi_Kernel_Compilation">http://elinux.org/Raspberry_Pi_Kernel_Compilation</a></li></ul>


</article>


<article>
<h1><a name=Monday-February-2 href=#Monday-February-2>#</a> Monday, February  2</h1>
<h2><a name=Monday-February-2-kernel-o-matic-amp-pi-finder href=#Monday-February-2-kernel-o-matic-amp-pi-finder>#</a> kernel-o-matic &amp; pi finder</h2>
<p>Published Friday:</p>
<ul><li><a href="https://github.com/adafruit/Adafruit-Pi-Kernel-o-Matic">https://github.com/adafruit/Adafruit-Pi-Kernel-o-Matic</a></li><li><a href="https://learn.adafruit.com/raspberry-pi-kernel-o-matic">https://learn.adafruit.com/raspberry-pi-kernel-o-matic</a></li></ul>

<p>Published a week or so before:</p>
<ul><li><a href="https://github.com/adafruit/Adafruit-Pi-Finder">https://github.com/adafruit/Adafruit-Pi-Finder</a></li><li><a href="https://blog.adafruit.com/2015/01/23/help-us-test-our-new-raspberry-pi-bootstrap-piday-raspberrypi/">https://blog.adafruit.com/2015/01/23/help-us-test-our-new-raspberry-pi-bootstrap-piday-raspberrypi/</a></li></ul>

<p>These have been a lot of my working time these last couple weeks, anoverlapping set of projects aimed at making the Pi (and eventually othersingle-board computers) more usable and Adafruit&rsquo;s hardware and tutorials bothmore accessible.  This has been frustrating and rewarding by turns.  I&rsquo;m tryingto reduce the complexity of a domain I just barely understand, in a lot ofways, which may be a good summary of software development in general.</p>
<p><a href="https://www.vagrantup.com/">Vagrant</a> is something I should have paid attentionto sooner.  The interfaces to virtualization are finally starting to overcomemy innate laziness on the whole question.</p>
<p>I just booted a Windows XP box for some reason.  It made that noise.  You knowthe one.</p>
<h2><a name=Monday-February-2-raspberry-pi-2 href=#Monday-February-2-raspberry-pi-2>#</a> raspberry pi 2</h2>
<p>Announced today:</p>
<ul><li><a href="http://www.raspberrypi.org/products/raspberry-pi-2-model-b/">http://www.raspberrypi.org/products/raspberry-pi-2-model-b/</a></li><li><a href="https://blog.adafruit.com/2015/02/02/raspberry-pi-2-model-b-armv7-with-1g-ram-is-here-benchmarks-and-more-raspberry_pi-raspberryp/">https://blog.adafruit.com/2015/02/02/raspberry-pi-2-model-b-armv7-with-1g-ram-is-here-benchmarks-and-more-raspberry_pi-raspberryp/</a></li><li><a href="http://hackaday.com/2015/02/02/introducing-the-raspberry-pi-2/">http://hackaday.com/2015/02/02/introducing-the-raspberry-pi-2/</a></li></ul>

<p>Expect this to prove interesting.  I&rsquo;ve been having a lot of conversationsabout the relative merits of small computing systems, and while this can hardlybe said to address all the complaints you might have about the Pi, boostingprocessor and RAM will do a lot for practical usability.</p>
<h2><a name=Monday-February-2-telling-composer-to-ignore-php-version-requirements href=#Monday-February-2-telling-composer-to-ignore-php-version-requirements>#</a> telling composer to ignore php version requirements</h2>
<p>Using <a href="https://getcomposer.org/">Composer</a> to set up a little project, I runinto the problem that the locally-installed PHP is a bit behind the times.</p>
<pre><code>brennen@exuberance 0:09:32 /home/brennen/code/project $  ./composer.phar installLoading composer repositories with package informationInstalling dependencies (including require-dev)Your requirements could not be resolved to an installable set of packages.
  Problem 1    - sparkfun/sparklib 1.1.9 requires php &gt;=5.5.17 -&gt; no matching package found.    - sparkfun/sparklib 1.1.8 requires php &gt;=5.5.17 -&gt; no matching package found.    - sparkfun/sparklib 1.1.7 requires php &gt;=5.5.17 -&gt; no matching package found.    - sparkfun/sparklib 1.1.6 requires php &gt;=5.5.17 -&gt; no matching package found.    - sparkfun/sparklib 1.1.5 requires php &gt;=5.5.17 -&gt; no matching package found.    - sparkfun/sparklib 1.1.4 requires php &gt;=5.5.17 -&gt; no matching package found.    - sparkfun/sparklib 1.1.3 requires php &gt;=5.5.17 -&gt; no matching package found.    - sparkfun/sparklib 1.1.2 requires php &gt;=5.5.17 -&gt; no matching package found.    - sparkfun/sparklib 1.1.11 requires php &gt;=5.5.17 -&gt; no matching package found.    - sparkfun/sparklib 1.1.10 requires php &gt;=5.5.17 -&gt; no matching package found.    - sparkfun/sparklib 1.1.1 requires php &gt;=5.5.17 -&gt; no matching package found.    - sparkfun/sparklib 1.1.0 requires php &gt;=5.5.17 -&gt; no matching package found.    - Installation request for sparkfun/sparklib ~1.1 -&gt; satisfiable by sparkfun/sparklib[1.1.0, 1.1.1, 1.1.10, 1.1.11, 1.1.2, 1.1.3, 1.1.4, 1.1.5, 1.1.6, 1.1.7, 1.1.8, 1.1.9].
Potential causes: - A typo in the package name - The package is not available in a stable-enough version according to your minimum-stability setting   see &lt;https://groups.google.com/d/topic/composer-dev/_g3ASeIFlrc/discussion&gt; for more details.
Read &lt;http://getcomposer.org/doc/articles/troubleshooting.md&gt; for further common problems.</code></pre>
<p>Well, ok.  I wrote a lot of that code, and I&rsquo;m pretty sure nothing I want outof it will break under a slightly stale PHP.  I check <code>./composer.phar help install</code>,and sure enough, there&rsquo;s an option to ignore this requirement:</p>
<pre><code>brennen@exuberance 0:13:21 /home/brennen/code/project $  ./composer.phar install --ignore-platform-reqs  Loading composer repositories with package informationInstalling dependencies (including require-dev)  - Installing sparkfun/sparklib (1.1.11)    Downloading: 100%         
Writing lock fileGenerating autoload files</code></pre>
<p>I never used to quite get the &ldquo;install an executable utility script in the rootdirectory of your project&rdquo; thing, but the whole paradigm is growing on me a littleas my projects accumulate little Makefiles and shell scripts to render HTML,publish revisions, or deploy packages.</p>

</article>


<article>
<h1><a name=Sunday-February-8 href=#Sunday-February-8>#</a> Sunday, February  8</h1>

<h2><a name=Sunday-February-8-systemd-amp-fsck href=#Sunday-February-8-systemd-amp-fsck>#</a> systemd &amp; fsck</h2>
<p>I just hit my first real frustration with systemd, which is running on theNovena.  The default storage here is a microSD card, and I&rsquo;ve had toforce-reboot this thing enough times that I&rsquo;d like to run <code>fsck</code> on theroot filesystem.</p>
<p>It used to be that you could call <code>shutdown -F</code> to force an fsck on boot.The old aliases still exist, but I think the thing I&rsquo;m supposed to do hereis <code>systemctl reboot</code>, and there doesn&rsquo;t seem to be an analogous pattern anymore.</p>
<p>On the other hand, some of the choices immediatly evident in the design of<code>systemctl</code> and <code>journalctl</code> seem interesting and not without merit.</p>

</article>


<article>
<h1><a name=Monday-March-2 href=#Monday-March-2>#</a> Monday, March  2</h1>

<h2><a name=Monday-March-2-python href=#Monday-March-2-python>#</a> python</h2>
<p>Significant whitespace isn&rsquo;t exactly a disaster, but on balance still feelsto me like it causes more problems than it solves:  Copy &amp; paste headaches,editor hassles, etc.</p>

</article>


<article>
<h1><a name=Thursday-April-9 href=#Thursday-April-9>#</a> Thursday, April  9</h1>

<h2><a name=Thursday-April-9-CGI-Fast-and-multi-param href=#Thursday-April-9-CGI-Fast-and-multi-param>#</a> CGI::Fast and multi_param()</h2>
<p>A little while ago, changes were made to <a href="http://search.cpan.org/~leejo/CGI-4.14/lib/CGI.pod">Perl&rsquo;s CGI.pm</a> because of a <a href="http://seclists.org/vulnwatch/2006/q4/6">classof exploits</a> arising from calling <code>param()</code> in list context.</p>
<p>I had code in a wrapper for <a href="https://github.com/brennen/display">Display</a> that called <code>param()</code> in list contextdeliberately:</p>
<pre><code># Handle input from FastCGI:while (my $query = CGI::Fast-&gt;new) {  my @params = $query-&gt;param('keywords');  print $d-&gt;display(@params);}</code></pre>
<p>In due course, I started getting warnings about calling <code>param()</code> in list context.They looked sort of like this:</p>
<pre><code>brennen@exuberance 18:46:13 /home/brennen/www (master) ★ perl display.fcgi 2&gt;&amp;1 | head -1CGI::param called in list context from package main line 38, this can lead to vulnerabilities. See the warning in "Fetching the value or values of a single named parameter" at /usr/local/share/perl/5.20.1/CGI.pm line 408.</code></pre>
<p>Problematic, since a variable containing that list is <em>exactly what I want</em>. Ongoogling, I found that in addition to the warning, CGI.pm had been amended toinclude <code>multi_param()</code> for <a href="http://search.cpan.org/~leejo/CGI-4.14/lib/CGI.pod#Fetching_the_value_or_values_of_a_single_named_parameter:">the cases</a> where you explicitly want a list.Ok, cool, I&rsquo;ll use that.</p>
<p>Fast forward to just now. <code>display.fcgi</code> is blowing up on my local machine. Why?</p>
<pre><code>[Thu Apr 09 18:28:29.606663 2015] [fcgid:warn] [pid 13984:tid 140343326992128] [client 127.0.0.1:41335] mod_fcgid: stderr: Undefined subroutine CGI::Fast::multi_param</code></pre>
<p>Well, ok, I upgraded Ubuntu a while back. Maybe I need to reinstall CGI::Fastfrom CPAN because the Ubuntu packages aren&rsquo;t up to date.  So:</p>
<pre><code>$ sudo cpan -i CGI::Fast</code></pre>
<p>No dice. What am I missing here?  Oh, right.  CGI::Fast inherits from CGI.pm.</p>
<pre><code>$ sudo cpan -i CGI</code></pre>
<p>Golden.</p>
<p>Granted, I should probably stop using CGI.pm altogether.</p>

</article>


<article>
<h1><a name=Monday-April-20 href=#Monday-April-20>#</a> Monday, April 20</h1>

<h2><a name=Monday-April-20-getting-recent-posts-from-pinboard-machine-readably href=#Monday-April-20-getting-recent-posts-from-pinboard-machine-readably>#</a> getting recent posts from pinboard machine-readably</h2>
<p>I&rsquo;ve been experimenting again with using Pinboard to track links of interest,and thought that maybe it&rsquo;d be a good idea to use these to add a linkblog backto p1k3.</p>
<p>First I thought ok, there&rsquo;s probably an API, which, sure enough, <a href="https://pinboard.in/api">istrue</a>.  Here&rsquo;s a one-liner that will grab JSON of recent posts bya user:</p>
<pre><code>curl "https://brennen:[brennen's password goes here]@api.pinboard.in/v1/posts/recent?count=25&amp;format=json"</code></pre>
<p>&hellip;but then I thought ok, this is dumb. I know there&rsquo;s RSS, so why not just usea standard format that could pull from other sources as well?</p>
<pre><code>curl https://feeds.pinboard.in/rss/u:brennen/</code></pre>
<p>Further thoughts:  Instead of doing this dynamically on the server, I couldjust periodically pull data into the p1k3 archives and render it using someservice.  I&rsquo;m getting ever-more leery of running any dynamic code where I don&rsquo;thave to, and even considering rewriting all of the p1k3 stuff to generatestatic files instead of building pages on the fly, so maybe this would be agood experiment.</p>

</article>


<article>
<h1><a name=Monday-January-18 href=#Monday-January-18>#</a> Monday, January 18</h1>

<h2><a name=Monday-January-18-moved-to-p1k3-com href=#Monday-January-18-moved-to-p1k3-com>#</a> moved to p1k3.com</h2>
<p>I&rsquo;ve decided to pick this project back up, but it seems like I&rsquo;ll probably bebetter at updating it if I <a href="https://p1k3.com/2016/1/16">integrate it</a> into<a href="https://p1k3.com/">p1k3.com</a>.  I&rsquo;ve copied all of these entries over intothe p1k3 tree, and new ones will appear there, but I&rsquo;ll leave this documentin place since I feel like it&rsquo;s uncool to break links.</p>

</article>


<article>
<h1><a name=tools-amp-toolchains-for-data-munging-amp-analysis href=#tools-amp-toolchains-for-data-munging-amp-analysis>#</a> tools &amp; toolchains for data munging &amp; analysis</h1>
<h2><a name=tools-amp-toolchains-for-data-munging-amp-analysis-csvkit href=#tools-amp-toolchains-for-data-munging-amp-analysis-csvkit>#</a> csvkit</h2>
<p>This is super handy.  Wish I&rsquo;d started using it sooner:</p>
<blockquote><p>csvkit is a suite of utilities for converting to and working with CSV, theking of tabular file formats.</p>
<p>&hellip;</p>
<p>csvkit is to tabular data what the standard Unix text processing suite (grep,sed, cut, sort) is to text. As such, csvkit adheres to the Unix philosophy.</p>
<ol><li>Small is beautiful.</li><li>Make each program do one thing well.</li><li>Build a prototype as soon as possible.</li><li>Choose portability over efficiency.</li><li>Store data in flat text files.</li><li>Use software leverage to your advantage.</li><li>Use shell scripts to increase leverage and portability.</li><li>Avoid captive user interfaces.</li><li>Make every program a filter.</li></ol></blockquote>
<p>&ndash; <a href="https://csvkit.readthedocs.org/en/0.9.0">csvkit 0.9.0</a></p>
<h2><a name=tools-amp-toolchains-for-data-munging-amp-analysis-jq href=#tools-amp-toolchains-for-data-munging-amp-analysis-jq>#</a> jq</h2>
<p>Also super handy, if a notch less intuitive.  Powerful DSL / pretty-printer /filter for working with JSON records at the command line.</p>
<ul><li><a href="http://stedolan.github.io/jq/">http://stedolan.github.io/jq/</a></li></ul>


</article>


<article>
<h1><a name=systemd-notes href=#systemd-notes>#</a> systemd notes</h1>
<ul><li><a href="https://letsgettechnicalblog.wordpress.com/2014/07/07/systemd-on-raspbian/">https://letsgettechnicalblog.wordpress.com/2014/07/07/systemd-on-raspbian/</a></li></ul>


</article>
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