User:bartman on SWiK

printable OLS/2008 schedule

Sat, 19 Jul 2008 18:52:42 -0700

I found the official schedule really hard to print. Here is a 1-page schedule.pdf and the original OOo spreadsheet.

wmiirc-lua updates

Tue, 15 Jul 2008 19:51:58 -0700

I finally got around to porting a few old features to wmiirc-lua.

There is now a mailing list for wmiirc-lua. Subscribe by emailing wmii-lua-subscribe@googlegroups.com.

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Git Screencast

Sun, 13 Jul 2008 17:51:33 -0700

Ian Ward posted a screencast of my Git intro talk. Thanks Richard for doing the audio, Ian for doing the screencast and post production, and Jay for hosting us.

four steps to reproducible Debian installs

Sun, 13 Jul 2008 11:52:30 -0700

For ever now some friends and I have been talking about making essential packages, which would pull in all the tools that we often use on Debian. So here goes...

With the power of the equivs package, this is actually a very short procedure.

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USB2.0 enclosure benchmark

Sat, 05 Jul 2008 17:49:19 -0700

I've noticed my laptop disk filling up... particularly in $HOME/work/*. Lots of little contracts, each involving at least the linux kernel tree of one vintage of another, are to blame.

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Linux Kernel Walkthroughs posted

Thu, 03 Jul 2008 20:51:34 -0700

Ian just posted the screen casts of the Linux Kernel Walkthroughs that I ran last week.

Here is the same video on google/video... it's a lot lower rez :(

Introducing the Ottawa Ruby folks to Git

Wed, 02 Jul 2008 08:52:34 -0700

I am giving another git talk for The Ottawa Group of Ruby Enthusiasts!.

The talk is on July 9th at 7:00 PM, at Infonium. I was told that they have room for 20 people.

I will post my slides after the talk.

Authenticating Linux against OSX LDAP directory

Sat, 28 Jun 2008 14:03:00 -0700

I was recently asked by a colleague, and now also a client, to look over the LDAP configuration on his Ubuntu boxen. He was having issues with the root account. The problem turned out being that the Ubuntu box was trying to get the root authentication from LDAP. It successfully found an LDAP account on the OSX LDAP server, but was unable to login since that account is disabled. The solution was to filter out the root account from the LDAP reply using the pam_filter directive in /etc/ldap.conf. Jay was also kind enough to document his setup for others that are trying to accomplish a similar task.

side note: Jay briefly showed me his OSX/Linux integration... looks pretty cool. Particularly the LDAP directory and automount of OSX exported volumes for users. OSX seems to make certain things really easy.

Canada Day Events 2008

Fri, 27 Jun 2008 12:06:25 -0700

Here is a list of Canada Day events for 2008 celebrations in Ottawa.

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Linux Kernel Walkthroughs

Fri, 13 Jun 2008 14:20:01 -0700

I will be kicking off a new series of talks at OCLUG later this month. The idea is not mine, but a copy of a similar series ran by Silicon Valley Linux Users Group. Kudos to them!

Here is the info on the first Kernel Walkthrough: Source Tree Layout. I will start off by covering the tree structure and talk a bit about the components, before handing control of the talk over to the audience and let them drive the types of things they would like to explore.

We are being hosted by the TheCodeFactory, which is a very cool concept. From the website:

"TheCodeFactory is a collaborative work space located in downtown Ottawa at 246 Queen Street, between Bank and Kent, above the Green Papaya Restaurant. TheCodeFactory is a clubhouse or water cooler for the Start-up community in Ottawa."

In short they are a place where startups can meet and collaborate way before they have any office space of their own. Ottawa being such a hotspot for startups, this is clearly a good idea.

is my usb device connected to a fast port?

Sat, 10 May 2008 06:16:12 -0700

I started a transfer last night to copy a 700M file to my USB key. It's still going. I figured that it might have been OHCI vs EHCI issue. I had to remind myself how to check.

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show more git info on zsh prompt

Fri, 09 May 2008 09:25:04 -0700

This is my third post on the topic. I have harshly assimulated MadCoder's configuration. Here is my new zsh prompt:

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git-vim

Wed, 30 Apr 2008 08:14:35 -0700

I have had an item on my todo list to improve my vim/git integration for a while. Today, I found git-vim on github. I was really impressed. So I forked it and hope to do some work on the project...

    git://tachyon.jukie.net/git-vim.git

First I will have to check if there is anything salvageable from my current vim scripts.

color your word

Sat, 12 Apr 2008 07:57:16 -0700

I just discovered a git feature that has eluded me since v1.4.3, when it was introduced. It's a way to colour differing words in git diff output. Maybe you don't know about it either... allow me demonstrate:

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show current git branch on zsh prompt (2)

Fri, 04 Apr 2008 08:56:18 -0700

NOTE: This post has been updated (again).

I previously wrote about showing the git branch name on the zsh prompt. Caio Marcelo pointed out that it didn't work very well because the git branch was being queried before the command was executed, and it should be after to catch git commands that change the branch, like git branch and git checkout.

He was right, here is a repost.

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how to track multiple svn branches in git

Mon, 03 Mar 2008 18:48:06 -0800

I must say that I am no fan SVN, but SVN and I get a long a lot better since I started using git-svn. Long ago a good friend of mine, Dave O'Neill, taught me how to handle multiple branches using git-svn. I had used that technique until Dave taught me how to do it better.

Recently I saw this blog post which referenced Dave's article talking about the first method. I guess Dave never got around to updating his blog with the better way. So I am going to do that here:

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fixing X for GeodeLX

Sat, 01 Mar 2008 11:47:18 -0800

Recently I have been doign a bit of contract work for Symbio Technologies. They have had me do various little projects part time. Most recently I got a chance to work on X.org video drivers for the Geode family.

Here is the progress...

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screen -c relative path bug

Tue, 08 Jan 2008 11:36:23 -0800

I must have recently upgraded to a new screen. My screenrc file was using the chdir directive so that the windows started inside would have a PWD I wanted them to. As soon as I tried to reconnect the screen session would die.

    screen -x
    Unable to open "screenrc"

I was able to find the bug on savannah that described the symptom quite well.

I then wrote a wrapper zsh function which fixes the problem:

    REAL_SCREEN=$(which screen)

    # convert the path passed via the -c parameter to an absolute one
    screen() {
            local max=$((${#argv}-1))
            for (( x=1 ; x<=$max ; x++ )) ; do
                    local flag="${argv[$x]}"
                    if [[ "x$flag" = "x-c" ]] ; then
                            local y=$(($x+1))
                            local word="${argv[$y]}"
                            if [[ "x${word[1]}" != 'x/' ]] ; then
                                    argv[$y]="$PWD/$word"
                            fi
                    fi
            done

            echo ${REAL_SCREEN} ${1+"$argv"}
            ${REAL_SCREEN} ${1+"$@"}
    }

kvm nfs hang

Tue, 08 Jan 2008 11:36:22 -0800

I ran into a strange NFS + KVM issue. Every so often under heavy NFS load my KVM client would hang retrying the nfs server. On the console the client was showing:

    nfs: server host not responding, still trying

I found this bug post which does not seem to have been resolved in 2.6.24.

Using the kvm flag -net nic,model=rtl8139 fixed the problem for me.

WeeChat spell suggestions

Sat, 05 Jan 2008 10:26:41 -0800

I recently decided to give WeeChat a try. I found that it had a nice new feel and less complicated windowing structure then irssi -- at least more intuitive to a vim user.

Here is my weechat config.

On debian you can install it with

    apt-get install weechat-curses weechat-scripts weechat-plugins

I really liked the spell-checking plugin which uses aspell to highlight misspelled words as I type them. One thing I missed was the ability to tab complete words from the /usr/share/words list. So I wrote a short lua script to do it...

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show current git branch in zsh

Wed, 19 Dec 2007 20:06:42 -0800

NOTE: This post has been updated.

Earlier today I saw a blog post titled "Git in your prompt" which showed how to get the current git branch to display in zsh and bash. I tried it on my setup and found it really slow, probably due having $HOME on NFS or having big git repos or maybe not enough ram.

Anyway, after looking at some zsh docs and blog posts, I had added caching to the idea. Now the git-branch is only queried on a directory change or on a command that matches *git*.

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wmiirc-lua kitchen sink repository

Mon, 17 Dec 2007 11:24:24 -0800

wmiirc-lua is a replacement for sh-based wmiirc that ships with the wmii window manager.

I have had some issues with the libixp and wmii packages under Debian. Particularly the problem is caused by the fact that libixp (and wmii use of the library) changes often but do not have any way to detect subtle changes in the API from the sources.

I decided to track everything in a kitchen sink repository that will include all the sources that need to be versioned and released together. That way what you try is the same thing I tried. Currently this includes

libixp imported from mercurial
wmii imported from mercurial
wmiirc-lua

This of course uses magic git powers; or more specifically git submodules. To follow along you will need git 1.5.3 or newer.

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protecting sshd from OOM killer

Wed, 12 Dec 2007 07:50:28 -0800

When Linux runs low on memory it tries to kill off applications that may be responsible for the high memory usage. It sometimes gets is all wrong, so the kernel has a way to tell it which processes are to be treated differently by the OOM killer.

I am using ssh to run some stress tests. Occasionally they cause memory to run out, and when I am not paying attention sshd is killed off... which means I cannot turn off the tests.

Here is a script that makes sshd immune to OOM killer.

    for pid in $(pidof sshd) ; do
            echo "disabling oom on pid $pid"
            echo -17 | sudo tee /proc/$pid/oom_adj > /dev/null
    done

NOTE: the sudo tee is a useful trick when you want to write to a file as root w/o spawning a subshell.

wmiirc-lua v0.2.1 remembers a bit more

Tue, 04 Dec 2007 20:42:44 -0800

wmiirc-lua is a replacement for sh-based wmiirc that ships with the wmii window manager.

In version 0.2.1 wmii will remember the last few programs that have been ran and the last few actions taken. It will put those entries at the beginning of the completion list. Frequent items can thus be selected with arrow keys and pushing enter.

In this release selecting works spaces with Mod4-[a-z] will not select the first view that starts with that letter, but rather the most recently used view that starts with the letter.

There have also been a few bug fixes, notably the core will now look in ~/.wmii-3.5 for plugins and core libraries before looking in system directories. That will solve the problem of someone using make install-user while having an older .deb installed.

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wmiirc-lua v0.2 has suspend and raw modes

Sat, 13 Oct 2007 18:15:53 -0700

wmiirc-lua is a replacement for sh-based wmiirc that ships with the wmii window manager.

The big improvement in version 0.2 is the client tracking support; this enables raw and suspend modes...

in raw mode the wmii key-bindings are ignored and all input is passed to the application.
in suspend mode, the process that created a particular window will be sent the STOP signal when the window is not in focus. I wrote this with firefox in mind; even when idle and off-screen my firefox gets woken up 100 times per second.

There were also several bug fixes in this release. You will still need to build libixp and wmii from hg as detained here.

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wmiirc-lua debianization

Mon, 01 Oct 2007 14:20:56 -0700

I just fixed the install scripts for wmiirc-lua. It is now possible to install wmiirc-lua in system directories and run from there. There is also a Wmii-lua session for the display managers (kdm, gdm, etc).

The new and improved way to install wmiirc-lua is to get libixp and wmii from hg and then...

    sudo apt-get install lua5.1 liblua5.1-0-dev liblua5.1-posix0 git-core

    git clone git://repo.or.cz/wmiirc-lua.git/

    cd wmiirc-lua
    git checkout debian
    make deb

    sudo debi

    install-wmiirc-lua

... restart X, and select Wmii-lua as your login session.

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zsh tip of the day - global aliases

Tue, 25 Sep 2007 12:47:12 -0700

Most shells have aliases. Last week I started using a new (to me) feature in zsh aliases. Zsh lets you create arbitrary substitutions for the command line, not just the executable.

The simple example of a alias would create a new command that acts like another with some parameters added to it:

    alias ll='ls -l'

You can also alias other common patterns in zsh. Say, you noticed that you used | tail -n10 a lot in your shell. You can alias it like so:

    alias -g TT10='| tail -n10"
    history TT10
    (10 lines follow)

You can also make this tail macro a bit more useful by not fixing it to use 10 lines:

    alias -g TT='| tail -n'
    history TT 10
    (10 lines follow)

Of course you need to pick alias names that will not conflict with normal usage.

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wmiirc-lua v0.1.1

Sat, 15 Sep 2007 07:51:01 -0700

Last night, just before midnight, I released v0.1 of wmiirc-lua. And then a few minutes later I had to release v0.1.1. Let this be a lesson to me, midnight is way too late to make releases.

So what do you get in v0.1.1?

a very fast and lean implementation of an event loop for wmii-3.5
all keyboard shortcuts from the (shell) wmiirc that ships with wmii-3.5
some ideas taken from wmii+ruby like more advanced keyboard shortcuts and plugins
a clock plugin, a load plugin
and most importantly a huge community of 3 users!

Why would you want to use wmiirc-lua over the default, or even over the fabulous wmii+ruby?

unlike wmii+ruby, wmiirc-lua can run with wmii-3.5
- debian/testing no longer has wmii-3.1 and according to the wmii website: wmii-3.1 is deprecated
wmiirc-lua is faster then the shell version because it doesn't have to exec things on event processing
- we communicate with wmii over an IXP socket directly
wmiirc-lua will not eat your laptop's battery life like ruby threading can
- powertop used to show ruby as the #1 source of CPU wakeups
- 300 wakeups/s with wmii+ruby and 1 wakeup/s with wmiirc-lua

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comparing two directories

Thu, 13 Sep 2007 10:35:16 -0700

In one of the project I am working on we have the build environment tarred up and stored in tgz files and committed in SVN. To avoid updating the same 300M tarball we decided to added incremental tarballs each time that we add new software to the build environment. But that's not the important bit...

I wanted to figure out what software was installed since the last tarballs were extracted. To do this I need to compare two directories and create a new tarball with all the new files. How do you diff two directories pro grammatically?

I came up with this...

    cp -ax orig-dir new-dir

    ... do whatever in new-dir ...

    diff -u <(find orig-dir -printf "%p %t\n" | cut -d / -f 2-) \
            <(find new-dir -printf "%p %t\n" | cut -d / -f 2-) \
    | grep -v '^[+-]'

And then I found out that I can do it with rsync...

    rsync -a orig-dir/ new-dir/

    ... do whatever in new-dir ...

    rsync -av --dry-run orig-dir/ new-dir/

git-rebase --interactive

Sun, 09 Sep 2007 18:39:45 -0700

MadCoder wrote today about git-rebase --interactive which is a new feature in git that allows you to easily reorder, or fix patches already applied to the current branch by editing a file... very neat.