Matthias Günther

Talk about Weechat another IRC client

2016-06-09T00:00:00+00:00

Follow me through my travel exploring the way to get Vim and Git running in a friendly coexistence.

Here are the slides of the talk:

and the videos of the talk:

Weechat - another IRC client (Part 1) from wikimatze on Vimeo.

Weechat - another IRC client (Part 2) from wikimatze on Vimeo.

You can find the source under bitbucket. I gave this talk at Vimberlin May 2016 Meetup.

Ranger a terminal browser for Vim

2016-05-30T00:00:00+00:00

Ranger is a file manager with VI key bindings. It provides a minimalistic and nice curses interface with a view on the directory hierarchy. I stumbled upon this tool during a vimberlin meetup.

Installation

Per package:

$ sudo apt-get install ranger

Or per source:

$ git clone git://git.savannah.nongnu.org/ranger.git /tmp/ranger && cd /tmp/ranger && git checkout v1.7.2 && sudo make install ```


## First start

```sh
$ ranger

TBD: Image

What you see are Miller columns, where the middle pane is the current directory, the left pane is the parent directory, and the right pane displays a preview for the file your are currently browser in the middle column. All in all it looks like Finder tool for Mac.

Text files are displayed with the less program. PDFs are converted to text for displaying preview and images are shown either with ASCII images or your default image viewer.

And get out of it via q.

Navigation shortcuts

gg ... Go to the top of the list
G ... Go to the bottom of the list
<C-f> ... Page down
<C-b> ... Page up
J ... Page down 1/2 page
K ... Page up 1/2 page
H ... Go back through navigation history
L ... Go forward through navigation history
o ... will open order context and after which filter you want to see the files
zh ... toggle show hidden files

Working with Files:

i ... display the file
E|I ... edit the file
r ... open file with the chosen program
cw ... rename file
/ ... search for files (n|p jump to next/previous match)
dd .. mark file for cut
ud ... uncut
p ... paste file
yy .. copy/yank file
zh ... show hidden files

General shortcuts

R ... reload current directory
<C-n> ... creates an new tab
<C-w> ... close the current tab
<Tab> ... jump to the next tab
<Shift-Tab> ... jump to the previous tab
q ... will quit ranger
? ... open the man, keybindings, commands, or settings

Command interface

:delete ... delete the selected file
:mkdir ... create a directory
:touch ... create a file
:rename ... rename file
:help ... show help (and then pressing k will print the shortcuts)

Customizing ranger

$ ranger --copy-config=all

It will create the rifle.conf, commands.py, commands_full.py, rc.conf, and scope.sh files in your ~/.config/ranger folder. rifle.conf is rangers file executor/opener.

E.g.:

#--------------------------------------------
# Audio without X
#-------------------------------------------
mime ^audio|ogg$, terminal, has mplayer  = mplayer -- "$@"
mime ^audio|ogg$, terminal, has mplayer2 = mplayer2 -- "$@"
mime ^audio|ogg$, terminal, has mpv      = mpv -- "$@"
ext midi?,        terminal, has wildmidi = wildmidi -- "$@"

commands_full.py defines commands for your rc.conf as well as terminal commands - if you want to create your own commands put them into commans.py. The scope.sh handles previews for ranger so that you can see the results of file in ranger instead of opening an external command.

rc.conf

Contains basic configuration like displaying hidden files and shortcuts

# Jumping around
map J     history_go -2
map K     history_go 0

My file is pretty empty because I want only that.

Vim command to start the browser mode

function RangerExplorer()
    exec "silent !ranger --choosefile=/tmp/vim_ranger_current_file " . system('echo "' . expand("%:p:h") . '" | sed -E "s/\ /\\\ /g"')
    if filereadable('/tmp/vim_ranger_current_file')
      exec 'edit ' . system('cat /tmp/vim_ranger_current_file | sed -E "s/\ /\\\ /g"')
      call system('rm /tmp/vim_ranger_current_file')
  endif
redraw!
endfun

map <Leader>r :call RangerExplorer()<CR>

There are a bunch of plugins out there, which all uses Ranger in different ways:

I prefer ranger.vim because it quickly opens a file browser and open the selected files in a new buffer.

VCS awareness

Edit rc.conf:

# Be aware of version control systems and display information.
set vcs_aware true

# State of the three backends git, hg, bzr. The possible states are
# disabled, local (only show local info), enabled (show local and remote
# information).
set vcs_backend_git enabled
set vcs_backend_hg disabled
set vcs_backend_bzr disabled

https://github.com/hut/ranger/wiki/VCS-integration

But then loading a big repo may slow down opening ranger.

Vimtex the perfect tool for working with tex and Vim and Zathura

2016-05-15T00:00:00+00:00

In the past I have used first vim-latex for compiling my LaTeX projects. And later on I discoverd vim-latexsuite, wich amazed me because of forward searching and backward searching which were totally new to me. Then the config stopped working for me when I updated vim.

Searching the famous LaTeX plugins for vim, I've discovered vimtex by Karl Yngve Lervåg. At first I was happy that it easily compiled my latex documents with \ll as well as opening the generated pdf with \lv. I wanted more, I wanted my forward and backward searching back.

(Works with latexmk 4.45, zathura 0.3.6 - requires zathura compiled with linsynctex, otherwise take another version but the forward/backward searching may not work, vimtex)

Benefits of using this plugin

you can chose between different PDF viewer (MuPDF, Zathura, Okular, qpdfview or SumatraPDF)
continuous compilation if a file has changed
text-objects:
- ae ... LaTeX environments (e.g. \begin{itemize})
- ac ... commands
- i$ ... inline math structure
- a$ ... whole math structure
motions and mappings:
- [[|]] ... move to next/previous section
- % ... move between matching delimeters
- dse|cse ... delete/change the surrounding environment
- dsc|csc ... delete/change the surrounding command
rename environments
omni completion, improved syntax highlighting and indentation

latexmk installation and configuration

Think of bibtex or your toc - everytime you have to run pdflatex several times to update the entries. Vimtex uses latexmk to compile the LaTeX document. latexmk is a perl script that runs the desired/necessary LaTeX command the correct number of times to resolve cross references.

The version of latexmk in the Ubuntu repositories is old (2012). I therefore suggest to remove it with sudo apt-get remove latexmk and then instead grab the latest version.

$ cd /tmp
$ wget http://users.phys.psu.edu/%7Ecollins/software/latexmk-jcc/latexmk-445.zip
$ unzip latexmk*.zip
$ sudo cp latexmk/latexmk.pl /usr/local/bin
$ sudo mv /usr/local/bin/latexmk.pl /usr/local/bin/latexmk

Normally, you don't have to create a custom latexmkrc because Vimtex does all the magic for your like adding the synctex option or specifying the output with -pdf - all of this is automatically done by the plugin.

But if you want to run latexmk manually, you can create your own ~/.latexmkrc. I have the following content:

# how pdflatex will be executed
$pdflatex = 'pdflatex --shell-escape %O %S';

A typical latexmk run looks like the following:

$ latexmk
Latexmk: This is Latexmk, John Collins, 22 April 2016, version: 4.45.
Latexmk: All targets (kanban.pdf) are up-to-date
$ vim kanban.tex # make some changes
$ latexmk
Latexmk: This is Latexmk, John Collins, 22 April 2016, version: 4.45.
Latexmk: applying rule 'pdflatex'...
Rule 'pdflatex': File changes, etc:
   Changed files, or newly in use since previous run(s):
      'kanban.tex'
------------
Run number 1 of rule 'pdflatex'
------------
------------
Running 'pdflatex --shell-escape -synctex=1  -recorder  "kanban.tex"'
------------
This is pdfTeX, Version 3.1415926-2.5-1.40.14 (TeX Live 2013/Debian)
 \write18 enabled.
entering extended mode
(./kanban.tex
LaTeX2e <2011/06/27>
Babel <3.9h> and hyphenation patterns for 7 languages loaded.
...
Output written on kanban.pdf (16 pages, 141131 bytes).
SyncTeX written on kanban.synctex.gz.
Transcript written on kanban.log.
Latexmk: References changed.
Latexmk: Log file says output to 'kanban.pdf'
Latexmk: applying rule 'pdflatex'...
Rule 'pdflatex': File changes, etc:
   Changed files, or newly in use since previous run(s):
      'kanban.aux'
      'kanban.out'
      'kanban.toc'
------------
Run number 2 of rule 'pdflatex'
------------
Running 'pdflatex --shell-escape -synctex=1  -recorder  "kanban.tex"'
------------
This is pdfTeX, Version 3.1415926-2.5-1.40.14 (TeX Live 2013/Debian)
 \write18 enabled.
entering extended mode
(./kanban.tex
LaTeX2e <2011/06/27>
Babel <3.9h> and hyphenation patterns for 7 languages loaded.
...
Output written on kanban.pdf (16 pages, 141117 bytes).
SyncTeX written on kanban.synctex.gz.
Transcript written on kanban.log.
Latexmk: Log file says output to 'kanban.pdf'
Latexmk: All targets (kanban.pdf) are up-to-date

The synctex option is needed for forward/backward search.

Ensure that libsynctex is on your system

One must also ensure that libsynctex exists in the system! The normal way to do it, is to:

$ sudo apt-get update
$ sudo apt-get install libsynctex-dev

Since I'm still running Ubuntu 14.04 I needed to install the packages on my own:

http://packages.ubuntu.com/xenial/libsynctex1
http://packages.ubuntu.com/xenial/libsynctex-dev

linsynctex1 is needed for libsynctex-dev.

The following script will help you installing it (either on amd64 or ):

#!/bin/bash
cd /tmp && rm -rf libsynctex*

if [ "$(uname -m)" == "x86_64" ]
then
  wget http://de.archive.ubuntu.com/ubuntu/pool/main/t/texlive-bin/libsynctex1_2015.20160222.37495-1_amd64.deb
  wget http://de.archive.ubuntu.com/ubuntu/pool/main/t/texlive-bin/libsynctex-dev_2015.20160222.37495-1_amd64.deb
else
  wget http://de.archive.ubuntu.com/ubuntu/pool/main/t/texlive-bin/libsynctex1_2015.20160222.37495-1_i386.deb
  wget http://de.archive.ubuntu.com/ubuntu/pool/main/t/texlive-bin/libsynctex-dev_2015.20160222.37495-1_i386.deb
fi

sudo dpkg -i libsynctex1* && sudo dpkg -i libsynctex-dev*

girara and zathura installation

I've decided to use zathura as my default pdfviewer because of it's vim bindings.

#!/bin/bash
GIRARA_VERSION=0.2.6
ZATHURA_VERSION=0.3.6

# otherwise the own girara compilation will not work
sudo apt-get remove libgirara-dev

# need for zathura compilation
sudo apt-get install libmagic-dev

rm -rf /tmp/girara /tmp/zathura

cd /tmp && git clone https://git.pwmt.org/pwmt/girara.git && cd girara && git checkout $GIRARA_VERSION && make && sudo make install
cd /tmp && git clone https://git.pwmt.org/pwmt/zathura.git && cd zathura && git checkout $ZATHURA_VERSION && make WITH_SYNCTEX=1 && sudo make install

Look during the compilation on the following line:

...
zathura build options:
CFLAGS  = -std=c11 -pedantic -Wall -Wno-format-zero-length -Wextra -pthread -I/usr/include/gtk-3.0
-I/usr/include/atk-1.0 -I/usr/include/at-spi2-atk/2.0 -I/usr/include/pango-1.0 -I/usr/include/gio-unix-2.0/
-I/usr/include/cairo -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/glib-2.0 -I/usr/lib/i386-linux-gnu/glib-2.0/include
-I/usr/include/harfbuzz -I/usr/include/freetype2 -I/usr/include/pixman-1 -I/usr/include/libpng12   -pthread
-I/usr/include/gtk-3.0 -I/usr/include/atk-1.0 -I/usr/include/at-spi2-atk/2.0 -I/usr/include/pango-1.0
-I/usr/include/gio-unix-2.0/ -I/usr/include/cairo -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/glib-2.0
-I/usr/lib/i386-linux-gnu/glib-2.0/include -I/usr/include/harfbuzz -I/usr/include/freetype2 -I/usr/include/pixman-1
-I/usr/include/libpng12   -pthread -I/usr/include/glib-2.0 -I/usr/lib/i386-linux-gnu/glib-2.0/include   -pthread
-I/usr/include/glib-2.0 -I/usr/lib/i386-linux-gnu/glib-2.0/include   -I/usr/include/glib-2.0
-I/usr/lib/i386-linux-gnu/glib-2.0/include      -I/usr/include/synctex
LIBS    = -lgirara-gtk3   -lgtk-3 -lgdk-3 -latk-1.0 -lgio-2.0 -lpangocairo-1.0 -lgdk_pixbuf-2.0 -lcairo-gobject
-lpango-1.0 -lcairo -lgobject-2.0 -lglib-2.0   -pthread -lgthread-2.0 -lglib-2.0   -pthread -lgmodule-2.0 -lglib-2.0
-lglib-2.0   -lpthread -lm -lsqlite3   -lmagic -lsynctex
DFLAGS  = -g
CC      = cc
make[1]: Entering directory `/tmp/zathura/po'
make[1]: Nothing to be done for `all'.
make[1]: Leaving directory `/tmp/zathura/po'
make[1]: Entering directory `/tmp/zathura/doc'
make[1]: Nothing to be done for `man'.
make[1]: Leaving directory `/tmp/zathura/doc'
[INSTALL] header files
[INSTALL] pkgconfig file
[INSTALL] man pages
[INSTALL] D-Bus interface definitions
[INSTALL] AppData file
[INSTALL] executeable file
 [INSTALL] desktop file
 make -C po install
 make[1]: Entering directory `/tmp/zathura/po'

And look if you can find -I/usr/include/synctex.

The make WITH_SYNCTEX=1 is the most important thing if you want to have forward/backward integration (see my issue report GitHub)

Please note that girara is needed for the zathura version 0.3.6.

vimtex basics

Install the plugin in the way you like (either manually or with some plugin manager). Next, just open your your tex file and press \ll|:VimtexCompileToggle. You will see in your statusline a message like latexmk compile: started continuous mode and it will open the pdf in your prefered pdf-viewer. If you don't configure anything, it will take the default system pdf viewer. In my case, I want zathura, so I need the following config:

let g:vimtex_view_method = 'zathura'

If you just want to see the plain generated pdf, it's nearly everything you need.

vimtex forward and backward search for zathura

To get forward/backward searching running, you need to open the file with vim's servername feature:

$ vim --servername vim test.tex

If one uses gvim or similar, then the client-server is automatically enabled.

Forward search is easy: Just place the cursor in your tex-file and press \lv you will then get the compiled PDF jump to this point with a green line:

"Vimtex forward search"

Backward search can be easily triggered if you just press <C-Enter> on the PDF and you jump right to the place in the terminal.

A quote from the author of the plugin:

This should work automatically with zathura, but it is also the only viewer where this will work automatically. In general, backward search should be configured on the viewer end. Luckily, vimtex may parse command line arguments that does this for zathura. Combined with the vi-keys in zathura, this is one of the main reasons I prefer zathura.

Useful vimtex commands

:VimtexTocOpen|:VimtexTocToggle: open a clickable toc in the left pane (q will close the window)
"Vimtex view toc"

:VimtexInfo: prints basic information

b:vimtex : kanban
  pid : 0
  root : '/home/wm/ownCloud/latex/projekte/kanban'
  aux : '/home/wm/ownCloud/latex/projekte/kanban/kanban.aux'
  log : '/home/wm/ownCloud/latex/projekte/kanban/kanban.log'
  out : '/home/wm/ownCloud/latex/projekte/kanban/kanban.pdf'
  tex : '/home/wm/ownCloud/latex/projekte/kanban/kanban.tex'
  base : 'kanban.tex'
  viewer
    xwin_id : 0
    class : 'Zathura'
    init : function('182')
    view : function('183')
    start : function('184')
    forward_search : function('185')
    latexmk_callback : function('186')
    latexmk_append_argument : function('187')
    xwin_exists : function('<SNR>178_xwin_exists')
    xwin_get_id : function('<SNR>178_xwin_get_id')

:VimtexCountWords|:VimtexCountLetters: count the number of words/letters in the document. It will also show the number of math environments, and similar.

  File: kanban.tex
  Encoding: utf8
  Sum count: 3265
  Words in text: 3156
  Words in headers: 66
  Words outside text (captions, etc.): 7
  Number of headers: 24
  Number of floats/tables/figures: 0
  Number of math inlines: 36
  Number of math displayed: 0

  (errors:8)

:VimtexLabelsOpen|:VimtexLabelsToggle: open table of labels.
"Vimtex view labels toc"
:VimtexCompileOutput: show the output form the compilation command (i.e. from latexmk)
:VimtexErrors: open quickfix window if there are errors or warnings.
:VimtexClean: clean auxilliary files like *.aux, *.out, and so on files. Use :VimtexClean! to remove everything, including the generated pfd file.

Migration RSS from FeedBurner to Feedio

2016-04-21T00:00:00+00:00

I was wondering: FeedBurner was acquired around 2011 by Google. Google announced that the feedburner API is going to be no longer available.

My intent to use this tool was to track how many people sign up and how many people subscribed to it. It surprised my, that feed for my blog wikimatze was still working. Time to look for alternatives and see how technology has changed.

RSS in the wild

Pages like blog.crazyegg.com mentioned 13 alternatives - but for most of them you have to pay money.

There are many wordpress plugins out there but since I'm using jekyll to build my site as a static HTML page, that is not even an alternative.

The site feedburner-alternatives.com mentions tools like feedblitz and specificfeeds.com. I tried feedblitz and created an RSS-feed of wikimatze.de but wasn't satisfied with the statistics and handling.

Than I stumbled across Danny Browns' post about if you blog really needs RSS. The author may be right that E-Mail subscribers are more open to change and that you can inform then more easier with new information (like changing the URL of your RSS feed).

I still like using RSS feed and using Tiny Tiny RSS to manage my feeds - there is even an app from which I can read new on the road. But I have also gathered positive experience with building up a mailing List for my PadrinoBook with mailchimp.com.

Why not taking both? This is what Danny Brown talks about in his post how he changed his mind about RSS. He mentioned a tool called feedio.co which should take care of this issues. I will show you some features of the tool in the last section of this article with some images.

Get your feedburner users

I made the error to link my RSS feed direct to feedburner. That means, that first all the traffic goes to the external service and second when I change the URL, my readers will not be informed about this.

First of all login to your feedburner account and follow the tab with Analyze:

"Get an overview of your feedburner RSS feed"

Next step would be to get an E-Mail to all of your subscribers you need to click on FeedBurner Email Subscriptions :

"Manager your feedburner RSS subscribers"

The good part is: I had no subscribers so I don't need to contact anyone. The bad part: I will probably lose my 19 subscribers of my old feed. Before I go on, I'll shortly explain the ways you can use to link your RSS feed.

Ways to link your RSS feed

You have several possibilities to link your RSS-feed. The classical way is to put a link in the head and/or link it in the navigation:

<html class="no-js" lang="en">
  <head>
    ...
    <link href="/atom.xml" rel="alternate" type="application/rss+xml" title="RSS feed of Matthias Günther">
  </head>
  <body>
    <nav>
        <ul class="dropdown menu large-8 medium-8 columns" data-dropdown-menu>
            ...
            <li><a href="/atom.xml" target="_blank"><i class="fa fa-rss"></i></a></li>
            ...
        </ul>
    </nav>
    ...
  </body>
  ...
</html>

"Make a RSS link in the head and in the navigation"

Browser like Firefox will then detect, that there is an RSS feed and will make highlight the RSS icon:

There is even a RSS icon plugin for the address bar:

"Firefox plugin to detect RSS feeds in the address bar"

Create a apache redirect for your atom

Let's say, that people should always signup under http://yourdomain/atom.xml and you need to track those things. A possible way would be to create a htaccess redirect and point the user to the location you like:

RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} !feedio [NC]
RewriteRule ^atom.xml/?$ http://www.feedio.co/@wikimatze/feed [R=302,L]
RewriteEngine Off

Decide if you want tracking or be lord over your domain. A mix between the two is also possible, let's say you offer visible RSS on your site which points to some third-party tool (like feedburner) and keep the <link href="/atom.xml" ... on your site.

But you need to be careful with your redirect: Ask the service you want to use, if a redirect is okay - not that their crawlers have problems with the loop.

Feedio

It's very easy to setup. All you have to do is to sign up with your twitter account. Your picture and bio will be taken automatically and you have to submit a link of your feed.

If there are some issues with your feed, one of their founders will help you setup your account. I had some issues with my feed, as Justin Butlion contacted my directly via mail:

Hey Matthias,

I was able to find and access your feed at http://wikimatze.de/atom.xml. There doesn't seem to be a redirect on this
feed which is ideal for us. The issue is that this actual feed has issues which you can see listed here -
http://www.rssboard.org/rss-validator/check.cgi?url=http%3A%2F%2Fwikimatze.de%2Fatom.xml. Only after the feed is valid
will we be able to crawl it.

I checked my RSS feed under rssboard.org and could see that my feed was not ready. This was also a good point to watch what formats are possible. You can get a nice overview atomenabled.org.

Feedio offers a very clean and easy subscription mechanism for your updates: It offers RSS, feedly or email:

"Nice sign up interface for email and RSS"

The dashboard gives you a high-level overview of your subscribers and how many people you reach with your entries:

"Nice analytics and dashboard"

You can use a more detailed view of your articles to and see social share buttons for them:

"Detail view of your articles and social share buttons"

Not so many options are editable on the profile page:

"Profile page"

If you want become my first RSS subscribe, you can do that here.

Feedio is still in development and not everything is working - but they are planning to release new features:

customizable email templates - I'm still using mailchimp.com but maybe I'll switch
google analytics integration - I'm not using it but why not
Advanced reporting
multiple users
...

They have many things on their agenda - let's see where the voyage will go.

Better zsh with Prezto

2016-01-21T00:00:00+00:00

I haven't been a user of the oh-my-zsh because I found it too complicated. I was only interested in it's completion features. Therefore I ripped out this component, copied the completions from it and did the configuration on my own.

Then I tried fish-shell but wasn't satisfied. It lacks completion but has very good autosuggestions and amazing VGA terminal colors for certain types of commands.

prezto jumps in here - it's an optimized version of oh-my-zsh. It is fast, has completions out of the box, and the nice autosuggestions feature of the fish-shell.

Here is what you get in the end

(This article has been written with zsh 5.0.2 (i686-pc-linux-gnu), xfce4-terminal 0.6.3git-f7c72e5, tmux 2.2, and prezto 31 Jul 2015)

Installation

Grab the code:

$ git clone --recursive https://github.com/sorin-ionescu/prezto.git "${ZDOTDIR:-$HOME}/.zprezto"

Setup the configs:

$ setopt EXTENDED_GLOB
$ for rcfile in "${ZDOTDIR:-$HOME}"/.zprezto/runcoms/^README.md(.N); do
ln -s "$rcfile" "${ZDOTDIR:-$HOME}/.${rcfile:t}"
done

If you do the steps above, you will get the following files on your system:

lrwxrwxrwx   1 wm   wm       32 Jan 20 20:41 .zlogin -> /home/wm/.zprezto/runcoms/zlogin
lrwxrwxrwx   1 wm   wm       33 Jan 20 20:41 .zlogout -> /home/wm/.zprezto/runcoms/zlogout
drwxrwxr-x   5 wm   wm     4096 Jan 20 20:43 .zprezto
lrwxrwxrwx   1 wm   wm       35 Jan 20 20:42 .zpreztorc -> /home/wm/.zprezto/runcoms/zpreztorc
lrwxrwxrwx   1 wm   wm       34 Jan 20 20:42 .zprofile -> /home/wm/.zprezto/runcoms/zprofile
lrwxrwxrwx   1 wm   wm       25 Jan 20 20:33 .zsh -> /home/wm/git/dotfiles/zsh
lrwxrwxrwx   1 wm   wm       32 Jan 20 20:42 .zshenv -> /home/wm/.zprezto/runcoms/zshenv
-rwx------   1 wm   wm   192662 Jan 20 20:48 .zsh_history

I didn't need all the files, so I just cloned the repository as described above and put the following line at the beginning of my .zshrc:

# Source Prezto.
if [[ -s "${ZDOTDIR:-$HOME}/.zprezto/init.zsh" ]]; then
  source "${ZDOTDIR:-$HOME}/.zprezto/init.zsh"
fi

Please note that you will be asked if you wish to overwrite your existing files (like .zshrc) or skip them, if they already exists.

Configure your .zpreztorc

This is the heart of prezto - here you enable modules and configure them.

The README says that the order of modules matters - I didn't follow them at first and was wondering why nothing changed:

Here is my .zpreztorc:

# Set the Prezto modules to load (browse modules).
# The order matters.
zstyle ':prezto:load' pmodule \
  'directory' \
  'utility' \
  'completion' \
  'git' \
  'prompt' \
  'syntax-highlighting' \
  'history-substring-search' \

directory: sets directory options
utility: defines aliases and functions (highlight matches when pressing <tab>)
completion: offers tab-completion from the zsh-completions project
git: displays git repository information in the terminal
prompt: defines a theme for your terminal
syntax-highlighting: offers fish-like-highlighting statuslinecolorful executables, underlined folders, ...
history-substring-search: type in a word and press up and down to cycle through matching commands

Prompt color themes

Press prompt -l to get an overview of the available fonts:

$ prompt -l
Currently available prompt themes:
agnoster cloud damoekri giddie kylewest minimal nicoulaj paradox peepcode powerline pure skwp smiley sorin
steeef adam1 adam2 bart bigfade clint elite2 elite fade fire off oliver pws redhat suse walters zefram

And you can change the theme by typing $ prompt <name-of-the-theme>

Custom prompt color theme

I found the josh prompt very handy but changed it with parts from mseri prompt to create my own one, where I can see the full path in colors. You can find the theme I'm using as a gist prompt_wikimatze_setup.

Place this file in ~/.zprezto/modules/prompt/functions/prompt_wikimatze_setup and set the theme in your .zpreztorc:

zstyle ':prezto:module:prompt' theme 'wikimatze'

Get rid of options-groups

When pressing tab to complete a command and you don't like the category menus, you need to comment out the following lines in ~/.zprezto/modules/completion/init.zsh:

# Group matches and describe.
zstyle ':completion:*:*:*:*:*' menu select
# zstyle ':completion:*:matches' group 'yes'
# zstyle ':completion:*:options' description 'yes'
# zstyle ':completion:*:options' auto-description '%d'
# zstyle ':completion:*:corrections' format ' %F{green}-- %d (errors: %e) --%f'
# zstyle ':completion:*:descriptions' format ' %F{yellow}-- %d --%f'
# zstyle ':completion:*:messages' format ' %F{purple} -- %d --%f'
# zstyle ':completion:*:warnings' format ' %F{red}-- no matches found --%f'
# zstyle ':completion:*:default' list-prompt '%S%M matches%s'
# zstyle ':completion:*' format ' %F{yellow}-- %d --%f'
# zstyle ':completion:*' group-name ''
# zstyle ':completion:*' verbose yes

All credit for this tipp goes to @jeromedalbert

Prezto without options-groups

Problems with tmux

After setting up everything, I started tmux and had a flickering cursor:

I tried a lot of different options in my .zpretzorc file but finally found the source of error in my tmux.conf file. I had to remove some active-window/active-border settings:

set-window-option -g window-style 'bg=#181818'
set-window-option -g window-active-style 'bg=black'
set-window-option -g pane-active-border-style ''

I think the issue is still there but I don't see it. The issue has something to do with asynchronity, as described in the issue on github.

Command-line completion speedup with prezto

Measure terminal startup time from a fresh oh-my-zsh:

time zsh -i -c "print -n"
zsh -i -c "print -n"  0,08s user 0,02s system 89% cpu 0,107 total

But command-line completions (like rake <tab>) take 2 seconds until it prints the available commands.

Measure terminal startup time in prezto:

time zsh -i -c "print -n"
zsh -i -c "print -n"  0,34s user 0,09s system 87% cpu 0,491 total

But rake <tab> takes around 1,2 seconds until it prints the available commands. And I'm doing this a lot more than opening new tabs, so that's a real speedup!

Scrum Master Certification

2015-07-24T00:00:00+00:00

Advanced Certified ScrumMaster training at it-agile

I had the pleasure to become a Certified ScrumMaster and did an advanced Certified ScrumMaster workshop at it-agile in Hamburg. Before and after the coaching (and even) before, you have to prepare yourself for the exam and learn more Scrum.

Read the Scrum Guide by Ken Schwaber and Jeff Sutherland.
Run tests from Scrum Open Assessment multiple times giving you coincidence in some tricky questions, run it several times to get comfortable with the questions.
Run the three tests from scrumsource as a starter to see how far your knowledge is.
Read A Guide to the SCRUM BODY OF KNOWLEDGE as an additional book for learning.
Run another test under proprofs.
Widen your horizon under the scrum.org forum.
During the test, don't try to google questions, because they can differ from the questions you experience, since scrum evolves older questions gets outdated.
The test is based on CSM Content Outline Learning Objectives make sure to get through these questions and be able to answer them.
To actually start the test, please go to the scrum alliance page.

Since I'm a person who better learns through learning I created my scrum notes in German. If you have additions or notes, you can find the sources on GitHub.

Meeting mantra at it-agile

Using Grub Customizer to manage the Bootloader

2015-07-09T00:00:00+00:00

I have Xubuntu and Windows installed on my machine. When booting my machine I can switch between those two systems. (This article was written for Xubuntu 14.04 and runs grub-customizer 4.06.)

Installation

sudo add-apt-repository ppa:danielrichter2007/grub-customizer
sudo apt-get update
sudo apt-get install grub-customizer

Usage

Once you have installed it, you can can start it with grub-customizer.

After that you can click on an entry and change the loading list:

The item at the first line will be the operating system which starts first.

After programming, it's good to move Windows to the top to enjoy playing for example Pillars of Eternity.

Encrypt Your External Device

2015-05-05T00:00:00+00:00

I recently bought a new External Hardware with 2 TB space (Transcend StoreJet 25M3 Anti-Shock 2TB and I use it as a backup for my music, images, and all other documents.

I always wanted to encrypt my whole device so here is how I started my journey. First let's check where our newly plugged in device can be found:

$ sudo fdisk -l

Disk /dev/sda: 256.1 GB, 256060514304 bytes
255 heads, 63 sectors/track, 31130 cylinders, total 500118192 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000a9645

Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048      206847      102400    7  HPFS/NTFS/exFAT
/dev/sda2          206848   295317503   147555328    7  HPFS/NTFS/exFAT
/dev/sda3       491730942   500117503     4193281    5  Extended
/dev/sda4       295317504   491728895    98205696   83  Linux
/dev/sda5       491730944   500117503     4193280   82  Linux swap / Solaris

Partition table entries are not in disk order

Disk /dev/sdb1: 2000.4 GB, 2000398934016 bytes
255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xa437ef40

  Device Boot      Start         End      Blocks   Id  System
/dev/sdb1              63  3907029167  1953514552+   7  HPFS/NTFS/exFAT

Now we need to unmount the device:

$ sudo umount /dev/sdb1

To encrypt the device we will use a tool called cryptsetup. Once you've installed it, please run cryptesetup --help, to see which cipher format are available for your machine:

$ cryptsetup --help

Default compiled-in key and passphrase parameters:
  Maximum keyfile size: 8192kB, Maximum interactive passphrase length 512 (characters)
  Default PBKDF2 iteration time for LUKS: 1000 (ms)

Default compiled-in device cipher parameters:
  loop-AES: aes, Key 256 bits
  plain: aes-cbc-essiv:sha256, Key: 256 bits, Password hashing: ripemd160
  LUKS1: aes-xts-plain64, Key: 256 bits, LUKS header hashing: sha1, RNG: /dev/urandom

cipher: is an algorithm doing the encryption or decryption
PBKDF2: stands for Password-Based Key Derivation Function 2 and applies various pseudorandom functions, HMAC (Hash Message Authentication Code), and salt over the input password in order to create a derived key for an block cipher
aes: stands for Advanced Encryption Standard and is a specification for the encryption of data.
LUKS1: stands for Linux Unified Key Setup and is disk-encryption specification developed by Clemens Fruhwirth (a Vienna guy) in 2004. The good thing about LUKS is that it is platform-independent for use in various tools, supports multiple passwords, stores all information in the partition header (users can transport or migrate data seamlessly), and it's free.

So LUKS1 uses aes under the hood for partition encryption, while aes uses PBKDF2 to cipher the key to encrypt your device.

In order to check the performance of the different encryption formats, you can use the cryptsetup benchmark:

$ cryptsetup benchmark

# Tests are approximate using memory only (no storage IO).
PBKDF2-sha1       254015 iterations per second
PBKDF2-sha256     216647 iterations per second
PBKDF2-sha512     147603 iterations per second
PBKDF2-ripemd160  308767 iterations per second
PBKDF2-whirlpool  149454 iterations per second
#  Algorithm | Key |  Encryption |  Decryption
aes-cbc       128b   177,8 MiB/s   185,4 MiB/s
serpent-cbc   128b    91,7 MiB/s   229,0 MiB/s
twofish-cbc   128b   197,8 MiB/s   247,8 MiB/s
aes-cbc       256b   143,6 MiB/s   148,1 MiB/s
serpent-cbc   256b    94,8 MiB/s   240,0 MiB/s
twofish-cbc   256b   212,7 MiB/s   262,4 MiB/s
aes-xts       256b   201,5 MiB/s   196,0 MiB/s
serpent-xts   256b   214,8 MiB/s   214,0 MiB/s
twofish-xts   256b   194,9 MiB/s   227,0 MiB/s
aes-xts       512b   143,4 MiB/s   148,1 MiB/s
serpent-xts   512b   209,4 MiB/s   212,4 MiB/s
twofish-xts   512b   229,8 MiB/s   225,0 MiB/s

As you can above, PBKDF2-sha512 has the lowest number of iteration per second, this maximizes the effort of the attacker, because he can't less iteration to get your password. Besides cbc (cipher-block chaining) and xts are possible ciphers. We will use xts because it's designed to support disk encryption efficiently and cbc is known to have some information leakage attacks. Since I'm having an SSD under the hood and USB 3 I want to have fast access so using 512 bit key with the twofish key block cipher is my choice. Normally 256 bit are good enough but I take 512 in favor with the little CPU overhead to be more save for the future.

Now let's put all the theory into practise:

$ sudo cryptsetup luksFormat -c twofish-xts -s 512 -h sha256 /dev/sdb1

WARNING!
========
This will overwrite data on /dev/sdb1 irrevocably.


Are you sure? (Type uppercase yes): YES
Enter passphrase:
Verify passphrase:

c ... set the cipher specification link
s ... set the key size in bits
h ... specifies the passphrase hash for open (I'm using the deprecated sha256 because sha512 was not working on my machine)

Next we use the luksOpen to mount the device:

$ sudo cryptsetup luksOpen /dev/sdb1 transcend
Enter passphrase for /dev/sdb1:

Once it's mounted you need to create a valid partition:

$ sudo mke2fs -j /dev/mapper/transcend -L transcend

mke2fs 1.42.9 (4-Feb-2014)
Filesystem label=transcend
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
122101760 inodes, 488378126 blocks
24418906 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
14905 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
  32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
  4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,
  102400000, 214990848

Allocating group tables: done
Warning: could not read block 0: Attempt to read block from filesystem resulted in short read
Writing inode tables: done
ext2fs_mkdir: Attempt to read block from filesystem resulted in short read while creating root dir

The -j options says that the filesystem should be ext3 journal and -L sets the volume label for the filesystem to new-volume-label.

I tried mkfs.exfat to create the filesystem but got later on problems with changing the owner rights.

It can be helpful to format the device in the exFAT format because it is both readable and writable by Mac, Windows, and Linux.

Finally edit fstab file to automount the plates on your machine. Luckily the thunar filesmanager does all the luksOpen thing automatically for me.

Talk about Git and Vim - maximize the joy and fun

2015-02-03T00:00:00+00:00

Follow me through my travel exploring the way to get Vim and Git running in a friendly coexistence.

Here are the slides of the talk:

You can find the source under bitbucket. I gave this talk at Vimberlin January 2015 Meetup.

Show the most common used terminal commands

2014-11-12T00:00:00+00:00

I watched recently a "Play by Play" video featuring Ben Orenstein. He is using a ton of command line alias and presented his work flow: He is searching the command line history file of the most common used terms. After that create some nice alias to save you time.

I asked Ben for the snippet:

@wikimatze history | awk '{a[$2]++}END{for(i in a){print a[i] " " i}}' | sort -rn | head
— Ben Orenstein (@r00k) July 16, 2014

All you have to do is to call:

wm~  % history | awk '{a[$2]++}END{for(i in a){print a[i] " " i}}' | sort -rn | head
  4716 git
  4526 vim
  3567 ls
  2140 cd
  1269 bundle
  877 sudo
  755 tig
  725 ..
  723 clear
  513 rm

Johannes Faigle pinged me on twitter a more sophisticated variant of the oh-my-zsh:

function zsh-stats() {
  fc -l 1 | awk '{CMD[$2]++;count++;}END { for (a in CMD)print CMD[a] " " CMD[a]/count*100 "% " a;}' | grep -v "./" | column -c3 -s " " -t | sort -nr | nl | head -n25
}

Now calling zsh-stats gives you the following overview:

wm~  % zsh-stats
     1  4716  18.8746%     git
     2  4526  18.1141%     vim
     3  3567  14.276%      ls
     4  2140  8.5648%      cd
     5  1269  5.07884%     bundle
     6  877   3.50997%     sudo
     7  755   3.02169%     tig
     8  725   2.90162%     ..
     9  723   2.89362%     clear
    10  513   2.05315%     rm
    11  406   1.62491%     d
    12  267   1.0686%      v
    13  241   0.96454%     rake
    14  238   0.952533%    exec
    15  222   0.888498%    tmux
    16  216   0.864484%    cf
    17  183   0.73241%     bash
    18  181   0.724406%    tmuxifier
    19  158   0.632354%    gem
    20  152   0.608341%    ruby
    21  146   0.584327%    fg
    22  145   0.580325%    mv
    23  141   0.564316%    ~
    24  121   0.484271%    padrino
    25  121   0.484271%    ack-grep

Now go out and create your personal aliases!

Google Chrome Start Problem

2014-10-21T00:00:00+00:00

After updating my system I could not start chrome anymore. When running chromium-browser or google-chrome I got the following error message:

ATTENTION: default value of option force_s3tc_enable overridden by environment.

MESA-LOADER: could not create udev device for fd 26
ATTENTION: default value of option force_s3tc_enable overridden by environment.
VMware: vmw_ioctl_command error Das Argument ist ungültig.
VMware: vmw_ioctl_command error Das Argument ist ungültig.
VMware: vmw_ioctl_command error Das Argument ist ungültig.
[11360:11360:0929/105136:ERROR:gl_renderer.cc(445)] Reached limit of pending sync queries.
[11360:11360:0929/105136:FATAL:gles2_implementation.cc(3487)] Check failed: query->CheckResultsAvailable(helper_).
[1]    11360 abort (core dumped)  chromium-browser

You can use the --disable-gpu option to start chrome without any gpu for the browser. You can disable this option permanently with in Settings/Show advanced settings and disable the setting for Use hardware acceleration when available in the System tab.

Installing Printer Driver For Brother HL-2240D Under Xubuntu

2014-09-30T00:00:00+00:00

You can go and install the default printer driver but that will not work for Duplex Printer under Xubuntu. The best choice is to install the official Brother Tools for Linux.

Get the sources

Since I have HL-2240D I need to grab the following script: http://support.brother.com/g/b/downloadlist.aspx?c=eu_ot&lang=en&prod=hl2240d_all&os=128. You can get the code direct from http://download.brother.com/welcome/dlf006893/linux-brprinter-installer-2.0.0-1.gz

Installation

Once you get the script, you need to run it ./linux-brprinter-installer-2.0.0-1 and follow the following installation dialog:

Input model name ->HL-2240D

You are going to install following packages.
   hl2240dlpr-2.1.1-1.i386.deb
   cupswrapperHL2240D-2.0.4-2.i386.deb
OK? [y/N] ->y

dpkg -x hl2240dlpr-2.1.1-1.i386.deb /
dpkg -x cupswrapperHL2240D-2.0.4-2.i386.deb /
dpkg-deb: building package `hl2240dlpr' in `hl2240dlpr-2.1.1-1a.i386.deb'.
dpkg -b ./brother_driver_packdir hl2240dlpr-2.1.1-1a.i386.deb
dpkg-deb: building package `cupswrapperhl2240d' in `cupswrapperHL2240D-2.0.4-2a.i386.deb'.
dpkg -b ./brother_driver_packdir cupswrapperHL2240D-2.0.4-2a.i386.deb
dpkg -i --force-all hl2240dlpr-2.1.1-1a.i386.deb
(Reading database ... 261952 files and directories currently installed.)
Preparing to unpack hl2240dlpr-2.1.1-1a.i386.deb ...
Unpacking hl2240dlpr (2.1.1-1) over (2.1.1-1) ...
Setting up hl2240dlpr (2.1.1-1) ...
dpkg -i --force-all cupswrapperHL2240D-2.0.4-2a.i386.deb
(Reading database ... 261952 files and directories currently installed.)
Preparing to unpack cupswrapperHL2240D-2.0.4-2a.i386.deb ...
 * Restarting Common Unix Printing System cupsd
   ...done.
Unpacking cupswrapperhl2240d (2.0.4-2) over (2.0.4-2) ...
Setting up cupswrapperhl2240d (2.0.4-2) ...
 * Restarting Common Unix Printing System cupsd
   ...done.

Will you specify the Device URI? [Y/n] ->n

Test Print? [y/N] ->y

wait 5s.
lpr -P HL2240D /usr/share/cups/data/testprint

Hope this article helps you a lot and makes you happy using your Brother printer in the right version for your PC.

Code Coverage Tools For Padrino

2014-07-24T00:00:00+00:00

This article is part of an ongoing series about my exploration of the Padrino web framework. If you want to read more about it please check out padrinobook.com. You sniff around in the sources of the book under GitHub.

Learn more about Padrino Book? Sign Up!

As long as your application exists, some developers leave others will join. It's good to have some metrics about certain code smells. A code smell is part of your source code which may be the root of a design problem but is not actually a bug. It's good to have some tools to be "lord of the smells" for Padrino - don't let smells lower the quality of your project.

(Note: This post is tested with padrino 0.12.2, simplecov 0.9, metric_fu 4.11.1, and ruby 2.1.2p95)

Available Tools

I will go through the following tools and will explain how you can use them.

simplecov: It will automatically detect the tests you are using Rubies 1.9's built-in Coverage library to gather code coverage data.
metric_fu: Creates churn, code smells, and other coverage tools that generate reports about your code.
codeclimate.com: Online tool for measuring quality and security for your application.

Simplecov

Add the gem to your Gemfile:

gem 'simplecov'

Next, I want to start the code coverage generation every time I run the tests. So we need to add the following line to the spec_helper.rb:

require 'simplecov'
SimpleCov.start

And that's all. Next time when you run the tests you can detect lines with the following output:

Coverage report generated for RSpec to ~/git/job-vacancy/coverage. 209 / 252 LOC (82.94%) covered.
/

After all tests have been passed, you can see the output in the coverage/index.html file:

Simplecover overview without any special configuration

Clicking on a single class will give you a brief overview which lines are not tested

It is also possible to divide parts of your application into several groups. Add options to the Simplecov.start block:

SimpleCov.start do
  add_group "Models", "app/models"
  add_group "Controllers", "app/controllers"
  add_group "Helpers", "app/helpers"
  add_group "Mailers", "app/mailers"
end

Simplecov - a more structured view of different components

metric_fu

Add the following line to your Gemfile:

gem 'metric_fu'

When this is done you need to start the metric_fu command from your command line:

$ ~/git/job-vacancy: metric_fu
******* STARTING METRIC reek
******* ENDING METRIC reek
******* STARTING METRIC flog
******* ENDING METRIC flog
******* STARTING METRIC flay
******* ENDING METRIC flay
******* STARTING METRIC saikuro
******* ENDING METRIC saikuro
******* STARTING METRIC roodi
******* ENDING METRIC roodi
******* STARTING METRIC cane
******* ENDING METRIC cane
******* STARTING METRIC churn
******* ENDING METRIC churn
******* STARTING METRIC stats
******* ENDING METRIC stats
******* STARTING METRIC hotspots
******* ENDING METRIC hotspots
******* SAVING REPORTS
******* GENERATING GRAPHS
*****Generating graphs
*****Generating graphs for tmp/metric_fu/_data/20140318.yml
all done

It will generate a tmp/metric_fu directory with the following contents:

tmp/metric_fu
├── _data
│   └── 20140318.yml
├── output
│   ├── app_app.rb.html
│   ├── app_controllers_page.rb.html
│   ├── app_controllers_sessions.rb.html
│   ├── app_controllers_users.rb.html
│   ├── app_helpers_page_helper.rb.html
│   ├── app_helpers_sessions_helper.rb.html
│   ├── app_helpers_users_helper.rb.html
│   ├── app_mailers_confirmation.rb.html
│   ├── app_mailers_registration.rb.html
│   ├── app_models_job_offer.rb.html
│   ├── app_models_user_observer.rb.html
│   ├── app_models_user.rb.html
│   ├── app_views_application.erb.html
│   ├── app_views_users_edit.erb.html
│   ├── app_views_users_new.erb.html
│   ├── bluff-min.js
│   ├── cane.html
│   ├── cane.js
│   ├── churn.html
│   ├── excanvas.js
│   ├── flay.html
│   ├── flay.js
│   ├── flog.html
│   ├── flog.js
│   ├── Gemfile.html
│   ├── Gemfile.lock.html
│   ├── hotspots.html
│   ├── index.html
│   ├── js-class.js
│   ├── lib_tasks_auth_token_attribute.rake.html
│   ├── reek.html
│   ├── reek.js
│   ├── roodi.html
│   ├── roodi.js
│   ├── saikuro.html
│   ├── spec_app_controllers_users_controller_spec.rb.html
│   ├── stats.html
│   └── stats.js
├── report.yml
└── scratch
    └── churn
        └── 873660ae5973b77b09c47d1dcf03577222095d6e.json

4 directories, 41 files

The following metrics are created by cane can be used if code quality thresholds are met.

churn measures the change ratio of files and you can use this indicator to have more code review, refactoring, more tests for this beast of a file.

flog a high flog score is an indicator for code complexity.

flay analyzes code similarities in your code base - good way to stay clean with DRY.

reek checks your classes and modules after code smells. Under the reek wiki you can find all code smells and what they actually mean.

hotspot a gathering of the flog, flay and reek score of the files in your application.

roodi scans your code and informs you about design issues you may have.

saikuro generates a list of cyclomatic complexity of each method found in your application.

Code Climate

Go to the website codeclimate.com and register. Once you are logged, you can add any ruby related open source project for free.

It will take a while till the metrics are generated for your application:

But when it's ready, you get a nice overview:

Or a more detailed overview of single classes:

Detailed information about a single file in Code Climate

Learn more about Padrino Book? Sign Up!

Highlight Bad Words In Vim

2014-07-11T00:00:00+00:00

Learn more about Padrino Book? Sign Up!

I'm currently writing, reviewing, and deleting a lot of words for my padrinobook. Words like easy, however, so, or just are growing in some parts of the book like a disease. The term for bad words is clutter, which I learned after reading On Writing Well by William Zinsser.

Clutter is not everywhere in the documents. It usually occurs when you are writing on a late evening or you are just thinking in technical terms.

After finishing a section it would be nice to browse through the text on the screen and scan for bad words. See them and get rid of them. It helps you to be more precise and you stay focus on what you want to write.

Learn more about Padrino Book? Sign Up!

Clutter Highlighting Function in Vim

The idea is to have a list of bad words and then give them a red background. To highlight the words vims ctermbg and ctermfg can be used in combination with the highlight function. After that we can use the match function in combination of the predefined color highlighting.

highlight TechWordsToAvoid ctermbg=red ctermfg=white

function MatchTechWordsToAvoid()
  match TechWordsToAvoid /\c\<\(obviously\|basically\|simply\|of\scourse\|clearly\|just\|everyone\sknows\|however\|so\|easy\)\>/
endfunction

Since I'm writing my book with the help of markdown I only want to highlight words the words if I'm on those files. Let's use the autocmd with the FileType option for markdown:

autocmd FileType markdown call MatchTechWordsToAvoid()

Now a file with many bad words will look like the following:

Highlight Bad Words in Vim

Learn more about Padrino Book? Sign Up!

RespImgPageCache not found in cache.inc file for Drupal

2014-06-05T00:00:00+00:00

I'm working with Drupal and installing a new module is probably no problem. After installing the webform module I got the following error on the QA system:

Fatal error: Class 'RespImgPageCache' not found in /var/www/releases/drupal/releases/20140603132022/includes/cache.inc on line 31

I removed the module, and clear the cache with drush cache-clear - in the end I still got the error.

After searching for this error I found the solution on a Drupal thread. I inserted the following snippet in the cache.inc file:

<?php
$cache_class_cache_page_old = variable_get('resp_img_cache_class_cache_page_old');
  if (isset($cache_class_cache_page_old)) {
    variable_set('cache_class_cache_page', $cache_class_cache_page_old);
  }
  else {
    variable_del('cache_class_cache_page');
  }
  variable_del('resp_img_cache_class_cache_page_old');

After this commit, you have to call some Drupal page where the loading will take a while. After the loading is finished you still get white pages now you have to remove the code snippet from above in another commit. Now the RespImgPageCache error was gone.

The strange thing was, that the webform module didn't had any dependencies to the RespImgPageCache module. Hopefully, this post will help other developers save a lot of time.

Global Gitignore

2014-04-08T00:00:00+00:00

For all my projects I was creating a local .gitignore files which keeps track of files I don't want to have under version control. The most common ones are for me .*.sw*, .DS_Store, log/**/* or tags files. You don't want to repeat yourself and you can put those file in a global gitignore file with the following command:

git config --global core.excludesfile ~/.gitignore

It will create an entry in your ~/.gitconfig file like the following:

[user]
  name = Matthias Guenther
  email = matthias@wikimatze.de
[apply]
  whitespace = nowarn
[core]
  editor = vim
  autocrlf = input
  excludesfile = ~/.gitignore
  pager = cat

My personal .gitignore has the following contents:

----------
| Jekyll |
----------
_site/*

--------
| Ruby |
--------
*.gem
*.thor
bundle/**/*


-----------
| Padrino |
-----------
application.css
application.js
coverage/*
tags.html


--------
| Vim  |
--------
*.spl
*.sw*
backup/*
tags
yankring.txt
.netrwhist


----------------------
| Logs and databases |
----------------------
*.log
*.sql
*.sqlite


----------------------
| OS generated files |
----------------------
.DS_Store
.DS_Store?
.Spotlight-V100
.Trashes
._*
Thumbs.db

Github Two-Factor Authentication Failed For HTTPS

2014-03-27T00:00:00+00:00

I heard from GitHub's Two-Factor Authentication nearly a couple of days ago when I was reading my RSS feed. I enabled it and couldn't push to any of my repositories anymore. Learn in this blog post how to fix it.

Two-Factor Authentication

"Is a process involving two stages to verify the identity of an entity trying to access services in a computer or in a network". Github solves this authentication with sending an SMS to a device which wants to push to their platform.

Enabling Two-Factor Authentication

Open your Account Settings.
Set up two-factor authentication.
You'll be given the option of setting up 2FA either through a text message, or through an app you can download onto your smart phone.

Once you enter in the number on your GitHub page, your account is verified.

Setting Up a Personal Access Token

Since you have enabled 2FA, you can create a personal access token.

Open your Account Settings.
Click on Applications - this is where you can find a section to create your Personal Access Token
Save the password in some encrypted file.

Testing your Personal Access Token

Run:

$ curl -u <token>:x-oauth-basic https://api.github.com/user

If everything works fine then you should get following JSON output:

{
  "login": "wikimatze",
  "id": 264708,
  "avatar_url": "https://avatars.githubusercontent.com/u/264708?",
  "gravatar_id": "9172bb642e29e9959f078f329308faa1",
  "url": "https://api.github.com/users/wikimatze",
  "html_url": "https://github.com/wikimatze",
  "followers_url": "https://api.github.com/users/wikimatze/followers",
  "following_url": "https://api.github.com/users/wikimatze/following{/other_user}",
  "gists_url": "https://api.github.com/users/wikimatze/gists{/gist_id}",
  "starred_url": "https://api.github.com/users/wikimatze/starred{/owner}{/repo}",
  "subscriptions_url": "https://api.github.com/users/wikimatze/subscriptions",
  "organizations_url": "https://api.github.com/users/wikimatze/orgs",
  "repos_url": "https://api.github.com/users/wikimatze/repos",
  "events_url": "https://api.github.com/users/wikimatze/events{/privacy}",
  "received_events_url": "https://api.github.com/users/wikimatze/received_events",
  "type": "User",
  "site_admin": false,
  "name": "Matthias Günther",
  "company": "",
  "blog": "http://wikimatze.de/about.html",
  "location": "Berlin",
  "email": "matthias@wikimatze.de",
  "hireable": true,
  "bio": "software developer, writer, hiker, jogger, and mobile apps lover",
  "public_repos": 64,
  "public_gists": 11,
  "followers": 54,
  "following": 65,
  "created_at": "2010-05-04T16:46:36Z",
  "updated_at": "2014-03-26T04:43:54Z",
  "private_gists": 0,
  "total_private_repos": 0,
  "owned_private_repos": 0,
  "disk_usage": 57682,
  "collaborators": 0,
  "plan": {
    "name": "free",
    "space": 307200,
    "collaborators": 0,
    "private_repos": 0
  }
}

If something went wrong, you should get a message like:


{
  "message": "Not Found",
  "documentation_url": "http://developer.github.com/v3"
}

Pushing to a HTTPS Github URL on Your Own

I had all my repositories checked out via HTTPS. But after enabling 2FA, I couldn't push to this repositories anymore.

$ git remote -v
  origin https://github.com/wikimatze/wikimatze.de.git (fetch)
  origin https://github.com/wikimatze/wikimatze.de.git (push)

$ git push origin master
  fatal: 'git@github.com/wikimatze/wikimatze.de.git' does not appear to be a git repository
  fatal: Could not read from remote repository.

  Please make sure you have the correct access rights
  and the repository exists.

I tried every combination of passwords, personal access token and even created a new ssh-key, but it didn't work. I had to change the remote URL to git@github.com:wikimatze/wikimatze.de.git to get it running again.

Pushing to a HTTPS GitHub URL on an Organization

I'm the maintainer of vimberlin.de and pushing my changes with the git@* remote URL hack did not work out very well:

$ git remote -v
  origin git@github.com/vimberlin/vimberlin.de.git (fetch)
  origin git@github.com/vimberlin/vimberlin.de.git (push)

$ git push
  fatal: 'git@github.com/vimberlin/vimberlin.de.git' does not appear to be a git repository
  fatal: Could not read from remote repository.

  Please make sure you have the correct access rights
  and the repository exists.

Most posts out there advices to use osxkeychain to save your credentials. Since I'm using Xubuntu for developing I had to search after another solution.

Use .netrc File To Store Credentials

The .netrc file contains login and initialization information for managing the auto-login process.

All you have to do is to setup your credentials in ~/.netrc:

machine github.com
login wikimatze
password <token>
protocol https

machine gist.github.com
login wikimatze
password <token>
protocol https

Where <token> is your personal access token. It would be silly to save your password in plain text.

Encrypt .netrc file with GPG

I assume that you already have your GPG key, you need to run the following command:

$ gpg --encrypt --armor --recipient matthias.guenther@wikimatze.de .netrc

And update the credentials helper:

$ git config --global credential.helper "netrc -f ~/.netrc.asc -v"

Now you should be able to push again.

Update About the organization push problem

Ryan mentioned all you have to do to push to an organization is use a colon before the username in the URL: Instead of git@github.com/vimberlin/vimberlin.de.git it should be git@github.com:vimberlin/vimberlin.de.git. This will mark the remote URL as an SSH path.

Thanks to Nico Hagenburger for reading an earlier draft of this post. He is working actually on livingstyleguide.org - a way to easily create living style guides with Markdown, Sass/SCSS and Compass for your Rails or Sinatra application.

Deploying Padrino Applications On Heroku

2014-03-13T00:00:00+00:00

Learn more about Padrino Book? Sign Up!

I was always asking myself how I can use cloud services like heroku to deploy Padrino applications without having an own server.

In this post I'm going to show you how you can a simple "Hello Padrino" app on heroku - ones without and ones with database interactions.

(Note: This post is tested with padrino 0.12.0, and heroku-toolbelt/3.4.1)

Installing Heroku

$ gem install heroku
Fetching: heroku-3.4.2.gem (100%)
 !    The `heroku` gem has been deprecated and replaced with the Heroku Toolbelt.
 !    Download and install from: https://toolbelt.heroku.com
 !    For API access, see: https://github.com/heroku/heroku.rb
Successfully installed heroku-3.4.2
Parsing documentation for heroku-3.4.2
Installing ri documentation for heroku-3.4.2
Done installing documentation for heroku after 1 seconds
1 gem installed

Hmm, the method above is working but I highly recommend you to follow the installations instructions from toolbelt.heroku.com page:

$ wget -qO- https://toolbelt.heroku.com/install-ubuntu.sh | sh

To check if everything went well, you can run the following command:

$ heroku version
heroku-toolbelt/3.4.1 (i686-linux) ruby/1.9.3

Hello World

Creating a new app:

$ padrino generate project hello-world-heroku
    create
    create  .gitignore
    create  config.ru
    create  config/apps.rb
    create  config/boot.rb
    create  public/favicon.ico
    create  public/images
    create  public/javascripts
    create  public/stylesheets
    create  tmp
    create  .components
    create  app
    create  app/app.rb
    create  app/controllers
    create  app/helpers
    create  app/views
    create  app/views/layouts
    create  Gemfile
    create  Rakefile
  skipping  orm component...
  skipping  test component...
  skipping  mock component...
  skipping  script component...
  applying  slim (renderer)...
     apply  renderers/slim
    insert  Gemfile
  skipping  stylesheet component...
 identical  .components
     force  .components
     force  .components

=================================================================
hello-world-heroku is ready for development!
=================================================================
$ cd ./hello-world-heroku
$ bundle
=================================================================

The next part is to create a route in app/app.rb:

module HelloWorldHeroku
  class App < Padrino::Application
    ...
    get "/" do
      "Hello Padrino On Heroku"
    end
  end
end

Next, you need to setup your account on heroku.com:

Next you need to click on "Create a new app":

Initialize an empty git repository, make an initial commit, and add the heroku remote:

$ cd hello-world-heroku
$ git init && git add . && git commit -m "Initial commit"
$ git remote add heroku git@heroku.com:hello-world-padrino.git

When everything is setup in the right way, you need to push:

$ git push --set-upstream heroku master
  Initializing repository, done.
  Counting objects: 15, done.
  Delta compression using up to 4 threads.
  Compressing objects: 100% (13/13), done.
  Writing objects: 100% (15/15), 7.88 KiB | 0 bytes/s, done.
  Total 15 (delta 0), reused 0 (delta 0)

  -----> Ruby app detected
  -----> Compiling Ruby/Rack
  -----> Using Ruby version: ruby-2.0.0
  -----> Installing dependencies using 1.5.2
         New app detected loading default bundler cache
         Running: bundle install --without development:test --path vendor/bundle --binstubs vendor/bundle/bin -j4 --deployment
         Fetching gem metadata from https://rubygems.org/.........
         Fetching additional metadata from https://rubygems.org/..
         Using minitest (4.7.5)
         Using i18n (0.6.9)
         Using rake (10.1.1)
         Using atomic (1.1.14)
         Using tzinfo (0.3.38)
         Using multi_json (1.8.4)
         Using mime-types (1.25.1)
         Using rack (1.5.2)
         Using tilt (1.4.1)
         Using bundler (1.5.2)
         Installing polyglot (0.3.3)
         Using thread_safe (0.1.3)
         Installing thor (0.17.0)
         Installing url_mount (0.2.1)
         Using treetop (1.4.15)
         Installing temple (0.6.7)
         Installing moneta (0.7.20)
         Using mail (2.5.4)
         Installing rack-protection (1.5.2)
         Installing http_router (0.11.0)
         Installing slim (2.0.2)
         Installing activesupport (4.0.2)
         Installing sinatra (1.4.4)
         Installing padrino-core (0.12.0)
         Installing padrino-helpers (0.12.0)
         Installing padrino-mailer (0.12.0)
         Installing padrino-cache (0.12.0)
         Installing padrino-admin (0.12.0)
         Installing padrino-gen (0.12.0)
         Installing padrino (0.12.0)
         Your bundle is complete!
         Gems in the groups development and test were not installed.
         It was installed into ./vendor/bundle
         Bundle completed (13.40s)
         Cleaning up the bundler cache.
  -----> Writing config/database.yml to read from DATABASE_URL
  -----> WARNINGS:
         You have not declared a Ruby version in your Gemfile.
         To set your Ruby version add this line to your Gemfile:
         ruby '2.0.0'
         # See https://devcenter.heroku.com/articles/ruby-versions for more information.
  -----> Discovering process types
         Procfile declares types -> (none)
         Default types for Ruby  -> console, rake, web

  -----> Compressing... done, 15.3MB
  -----> Launching... done, v4
         http://hello-world-padrino.herokuapp.com/ deployed to Heroku

  To git@heroku.com:hello-world-padrino.git
   * [new branch]      master -> master
  Branch master set up to track remote branch master from heroku.

If you now call hello-world-herokuapp.com you can see it and your done.

You can find the code for this application on GitHub padrino-hello-world-heroku

Database Deployments With Heroku

Let's create a new application:

$ padrino g project hello-world-heroku-postgres -d activerecord -a postgres
    create
    create  .gitignore
    create  config.ru
    create  config/apps.rb
    create  config/boot.rb
    create  public/favicon.ico
    create  public/images
    create  public/javascripts
    create  public/stylesheets
    create  tmp
    create  .components
    create  app
    create  app/app.rb
    create  app/controllers
    create  app/helpers
    create  app/views
    create  app/views/layouts
    create  Gemfile
    create  Rakefile
  applying  activerecord (orm)...
     apply  orms/activerecord
    insert  Gemfile
    insert  Gemfile
    insert  app/app.rb
    create  config/database.rb
  skipping  test component...
  skipping  mock component...
  skipping  script component...
  applying  slim (renderer)...
     apply  renderers/slim
    insert  Gemfile
  skipping  stylesheet component...
 identical  .components
     force  .components
     force  .components

=================================================================
hello-world-heroku-postgres is ready for development!
=================================================================
$ cd ./hello-world-heroku-postgres
$ bundle
=================================================================

Go to your app and select under "Resources" the "Get Add-ons" link and chose the "Heroku Postgres" addon with the help:

You can also run the following command which does the same:

$ heroku addons:add heroku-postgresql

Adding heroku-postgresql on hello-world-heroku-postgres... done, v3 (free)
Attached as HEROKU_POSTGRESQL_TEAL_URL
Database has been created and is available
 ! This database is empty. If upgrading, you can transfer
 ! data from another database with pgbackups:restore.
Use `heroku addons:docs heroku-postgresql` to view documentation.

Hmmm, let's go into the help:

$ heroku addons:docs heroku-postgresql

It will open the URL https://devcenter.heroku.com/articles/heroku-postgresql. Calling:

$ heroku config | grep HEROKU_POSTGRESQL
HEROKU_POSTGRESQL_TEAL_URL: postgres://yxkscmfxkhsvfd:hnGMVRPWmBQ06Bi3ujqP21Orl4@ec2-79-125-21-60.eu-west-1.compute.amazonaws.com:5432/dev751q4jd401b

gives us the host URL, the user, the port, as well as the password. You can get the same information under the URL https://postgres.heroku.com/databases.

Since we now have the information about our database, it's time to edit config/database.rb:

ActiveRecord::Base.configurations[:production] = {
  :adapter   => 'postgresql',
  :database  => 'dev751q4jd401b',
  :username  => 'yxkscmfxkhsvfd',
  :password  => 'hnGMVRPWmBQ06Bi3ujqP21Orl4',
  :host      => 'ec2-79-125-21-60.eu-west-1.compute.amazonaws.com',
  :port      => 5432
}

Now, it's time to push our app on heroku:

$ git push heroku master
Initializing repository, done.
Counting objects: 22, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (20/20), done.
Writing objects: 100% (22/22), 9.43 KiB | 0 bytes/s, done.
Total 22 (delta 4), reused 0 (delta 0)

-----> Ruby app detected
-----> Compiling Ruby/Rack
-----> Using Ruby version: ruby-2.0.0
-----> Installing dependencies using 1.5.2
       New app detected loading default bundler cache
       Running: bundle install --without development:test --path vendor/bundle --binstubs vendor/bundle/bin -j4 --deployment
       Fetching gem metadata from https://rubygems.org/.........
       Fetching additional metadata from https://rubygems.org/..
       Using rake (10.1.1)
       Using i18n (0.6.9)
       Using minitest (4.7.5)
       Using tzinfo (0.3.38)
       Using builder (3.1.4)
       Using activerecord-deprecated_finders (1.0.3)
       Using arel (4.0.2)
       Using rack (1.5.2)
       Using mime-types (1.25.1)
       Using polyglot (0.3.4)
       Using tilt (1.4.1)
       Installing thor (0.17.0)
       Using bundler (1.5.2)
       Using pg (0.17.1)
       Installing multi_json (1.9.0)
       Installing url_mount (0.2.1)
       Installing moneta (0.7.20)
       Using treetop (1.4.15)
       Installing temple (0.6.7)
       Using mail (2.5.4)
       Installing atomic (1.1.15)
       Installing rack-protection (1.5.2)
       Installing slim (2.0.2)
       Installing http_router (0.11.1)
       Installing sinatra (1.4.4)
       Installing thread_safe (0.2.0)
       Installing activesupport (4.0.3)
       Installing activemodel (4.0.3)
       Installing padrino-core (0.12.0)
       Installing padrino-mailer (0.12.0)
       Installing padrino-gen (0.12.0)
       Installing padrino-helpers (0.12.0)
       Installing activerecord (4.0.3)
       Installing padrino-cache (0.12.0)
       Installing padrino-admin (0.12.0)
       Installing padrino (0.12.0)
       Your bundle is complete!
       Gems in the groups development and test were not installed.
       It was installed into ./vendor/bundle
       Bundle completed (18.14s)
       Cleaning up the bundler cache.
-----> Writing config/database.yml to read from DATABASE_URL
-----> WARNINGS:
       You have not declared a Ruby version in your Gemfile.
       To set your Ruby version add this line to your Gemfile:
       ruby '2.0.0'
       # See https://devcenter.heroku.com/articles/ruby-versions for more information.
-----> Discovering process types
       Procfile declares types -> (none)
       Default types for Ruby  -> console, rake, web

-----> Compressing... done, 16.1MB
-----> Launching... done, v6
       http://hello-world-heroku-postgres.herokuapp.com/ deployed to Heroku

To git@heroku.com:hello-world-heroku-postgres.git
 * [new branch]      master -> master

Now let's create a model:

$ padrino g model users name:string email:text
   apply  orms/activerecord
  create  models/users.rb
  create  db/migrate/001_create_users.rb

Before pushing our changes we need to run the migrations:

$ heroku run rake db:migrate
Running `rake db:migrate` attached to terminal... up, run.1057
==  CreateUsers: migrating ====================================================
-- create_table(:users)
   -> 0.0234s
==  CreateUsers: migrated (0.0236s) ===========================================

Now we need to create some data with the following query:

INSERT INTO users (name, email) VALUES ('Matthias', 'matthias@wikimatze.de');

Next we need to edit our view app/app.rb:

module HelloWorldHeroku
  class App < Padrino::Application
    ...
    get "/" do
      user = Users.find(1)
      "Hello #{user.name}\n Your email is: #{user.email}"
    end
  end
end

After pushing the changes, you can call http://hello-world-heroku-postgres.herokuapp.com and see the lovely output.

Learn more about Padrino Book? Sign Up!

Making Firefox as Fast as Chrome

2013-12-05T00:00:00+00:00

Learn in this article how you can make Firefox as fast as Chrome again.

I can remember that in the past some coworker says to me: "Why are you using Firefox and not the faster Chrome?" Hmm, I have always been using Firefox and never saw a reason why to use another browser. But I installed Chrome, it feels faster, and it consumes less CPU and memory of my system. The ecosystem and the look and feel is typical for a Google product: It works, is intuitive, and you know it works. It is not difficult to sync your bookmarks, settings, prefill forms, and even passwords => just everybody has nowadays a gmail account and this is how all the magic works.

But being a German, it always felt wrong to send Google information about my web experience, which buttons I press, what plugins I use and so on. Since I'm a big Vim fan I heard of a plugin called Vimium which enables keyboard shortcuts for navigating webpages without using the mouse, I installed it but was not really happy with it because it hasn't all the shortcuts I really want and it was difficult to create custom mappings, as well as handling bookmarks. Than during a vimberlin meetup I saw @andrewradev using Vimperator and it was a blast: He was very fast and doing all the things I wanted but never could do with Vimium. That was a turning point to give Firefox a new chance. I spent one weekend to learn most of Vimperators shortcuts and create a vimperatorrc.

But than came the release of Xubuntu 13.10 and I installed a fresh new system ...

Slow Firefox

After everything was installed and I was ready to use the new system. Starting Firefox was a nightmare, everything is slow. Thanks to my friend @jcavena from Kansas City - he gave me starting point to solve this issue and not spending more hours on it:

@wikimatze how many plugins on Firefox vs chrome?
— JC (@jcavena) October 21, 2013

I didn't had any plugins, only the basic installation with the default settings. I spend the evening fiddling around with the settings, tried this and that, checked my Internet connection, but all what I did was senseless. Firefox was loading 2000 times slower than Chrome. But don't give up in such situations, just clear your mind and think about what you want solve.

Fast Firefox

I stick around the Internet and found the about:config setting in Firefox (it's nearly the same when you call the chrome://settings/ URL in Chrome but has more options). This is the place where you can change security, stability, and performance. That what I was searching for and this is the place you can't find in the normal graphical settings of Firefox. There you can see a list preferences names with either string, integer, or boolean values. Than I stumbled upon the network.dns.disableIPv6 option. There is an error in IPv6-capable DNS servers where an IPv4 address is returned although an IPv6 was requested. Firefox can recover from this error but due to lack of performance. So my solution was to setting this option to true.

Reduce Firefox Memory and Cache Usage

Next, create the config.trimonminimize as a boolean value and set it's value to true. This will swap out memory when the program is minimized.

If you have enough memory, you can set the browser.cache.disk.enable and the browser.cache.memory.enable value to false.

Pipelining

Set the values of network.http.pipelining and network.http.proxy.pipelining to true. Next set the value network.http.pipelining.maxrequests to 8. This in combination with the pipelining options, Firefox will send 8 requests to a page and this results in a faster load of the page.

Create the new value nglayout.initialpaint.delay with the value of 0. This will load a page initially but take longer till the whole page is rendered. Normally, Firefox renders web pages incrementally, it displays what's been received before the entire page has been downloaded.

Fast Rendering

Create the new value content.notify.interval to 500000. This preference specifies the minimum amount of time to wait between reflows to 1/2 of a second. Lowering the interval will lower the perceived page loading time but increase the total loading time. To make use of the content.notify.interval setting you need to add the boolean setting content.notify.ontime to true. This means that pages are not reflowed at an interval any higher than that specified by the content.notify.interval.

Frequency Mode

Create the new value content.switch.threshold and set it to 250000. When a page is loaded, there is a high frequency and low frequency level. The high frequency mode is active when the user moves the mouse or uses the keyboard - so it allows higher UI responsiveness. On the other hand, the low frequency mode is on, when the user is reading the page. Raising the value will make the application more responsive at the expense of page load time. In order to make use of this option, you need to create the new value content.interrupt.parsing and set it to false. Parsing a page will not be interrupted by user and the page is loaded faster. But that means, that the application is unresponsive until the parsing the site is complete.

Session History Entries

Set the browser.sessionhistory.max_entries to 5 - you won't surf more than 5 of the websites we previously surfed before, and there is really no need to store more than that in the session.

Increase Page Loading

Next, create the new value nglayout.initialpaint.delay, chose a new integer type and set the value to 0. This will speed up page loading by intentionally telling Firefox to avoid waiting during certain parts of page loading.

Further Improvements

The following improvements are based on Gheorghe Sarcov.

Set browser.display.show_image_placeholders to false - this stops the display of placeholders while images are loading to speed up the page
Set browser.tabs.animate to false - this disables all tab animation features (e.g. when you click the ‘New Tab’ (+) button) to make the tab interface feel quicker.
Set network.prefetch-next to true - this setting can automatically prefetch (load) the contents of pages linked to by the page you are viewing e.g. to load the homepage in the background, making it quicker for you to view next if you want to.

Final Thoughts

There is not the perfect setup here for everyone. You can type in about:cache?device=memory and see your current number of entries, maximum storage size, storage in use and inactive storage. Chrome make better use of a modern multi-core CPU, as described under howtogeek.com - where Firefox uses a single-process architecture.

Browsing Padrino's Code Base With Ctags in Vim

2013-10-17T00:00:00+00:00

Learn more about Padrino Book? Sign Up!

Working effectively with ctags has been a topic I avoided for a long time because I was too lazy to invest the time to learn about it.

I was working on my application and needed to constantly consult Padrino's API docs in the browser. It would have been more effective if I could do the searching directly in Padrino's code. Even better would be if I didn't have to leave the terminal and could stay in the flow of coding. It's possible with ctags!

What is ctags

Ctags is a tool which make it easy for you to shift rapidly through code. It does this by indexing classes, methods, variables and other things. All this information is stored in a tags file - one line in this file contains one tag.

Ctags is the tool to browse a large code base like Padrino, where you might not know the project layout and class/method definitions. Being able to jump forward and backward between variables, classes, modules, and methods is essential in getting to know a code base.

Installing ctags

Depending on your operation system, you can install it on Ubuntu/Debian with the following packages:

$ sudo apt-get install exuberant-ctags

Why I'm installing exuberant-ctags instead of ctags? Ctags was originally written by Ken Arnold (the author of the "Rogue video game") and was first introduced in BSD Unix. Exuberant ctags is a variant of ctags and was distributed with Vim 6.0. The main benefit of exuberant ctags is that it support over 40 languages and has regular expression support which make it easier to create your own custom language parser for creating the tags file. The tags contains the collected information about the things you want to know.

Generating ctags for the Padrino's code base

Clone Padrino and run the following command at the root of the project:

$ git clone https://github.com/padrino/padrino-framework
$ cd padrino-framework
$ ctags -R .

The command will run recursively through the directory and will tag all sources and files it can find. During running the ctags -R . command I got the following error:

ctags: Warning: ignoring null tag in padrino-admin/lib/padrino-admin/generators/templates/assets/javascripts/bootstrap/bootstrap.min.js

Okay, we are actually interested in all the things, except JavaScript. Let's exclude those files with the following command:

    $ ctags -R --exclude="*.js" .

If you are done with the command, you have a tags file created in the current directory. Let's open the generated tags file and try to understand the basic nature of the file:

    !_TAG_FILE_FORMAT   2   /extended format; --format=1 will not append ;" to lines/
    !_TAG_FILE_SORTED   1   /0=unsorted, 1=sorted, 2=foldcase/
    !_TAG_PROGRAM_AUTHOR    Darren Hiebert  /dhiebert@users.sourceforge.net/
    !_TAG_PROGRAM_NAME  Exuberant Ctags //
    !_TAG_PROGRAM_URL   http://ctags.sourceforge.net    /official site/
    !_TAG_PROGRAM_VERSION   5.9~svn20110310 //
    <<  padrino-core/lib/padrino-core/logger.rb /^    def <<(message = nil)$/;" f
    ==  padrino-core/lib/padrino-core/mounter.rb    /^    def ==(other)$/;" f   class:Padrino.Mounter
    AbstractFormBuilder padrino-helpers/lib/padrino-helpers/form_builder/abstract_form_builder.rb   /^      class AbstractFormBuilder # @private$/;"    c   class:Padrino.Helpers.FormBuilder
    AbstractHandler padrino-helpers/lib/padrino-helpers/output_helpers/abstract_handler.rb  /^      class AbstractHandler$/;"   c   class:Padrino.Helpers.OutputHelpers
    AccessControl   padrino-admin/lib/padrino-admin/access_control.rb   /^    module AccessControl$/;"  m   class:Padrino.Admin
    AccessControlError  padrino-admin/lib/padrino-admin/access_control.rb   /^    class AccessControlError < StandardError # @private$/;"   c   class:Padrino.Admin
    Account padrino-admin/test/fixtures/data_mapper.rb  /^class Account$/;" c
    Actions padrino-admin/lib/padrino-admin/generators/actions.rb   /^      module Actions$/;"  m   class:Padrino.Generators.Admin
    ...

The header of each tag file gives you basic information about the creation of the file:

    !_TAG_FILE_FORMAT   2   /extended format; --format=1 will not append ;" to lines/
    !_TAG_FILE_SORTED   1   /0=unsorted, 1=sorted, 2=foldcase/
    !_TAG_PROGRAM_AUTHOR    Darren Hiebert  /dhiebert@users.sourceforge.net/
    !_TAG_PROGRAM_NAME  Exuberant Ctags //
    !_TAG_PROGRAM_URL   http://ctags.sourceforge.net    /official site/
    !_TAG_PROGRAM_VERSION   5.9~svn20110310 //

As you can see, the tags are sorted, folded, and you can see the version of ctags in which they were created. If you take a look close in the example above, you can see detect a tag name schema: Let's consider our first tag:

<<  padrino-core/lib/padrino-core/logger.rb /^    def <<(message = nil)$/;" f

First of all you have the tagname <<, then a tab as separator (it isn't visible in the code examples above), then tagfile padrino-core/lib/padrino-core/logger.rb where the tag can be found, followed by a tab, and finally the tagaddress the exact location of the tag inside the tagfile. The tagaddress is a regular expression - the special characters in a search pattern are ^ (begin-of-line) and $ (indicates the end of the line). Finally a term marked with ;" which indicates if the tag is either a class (c), module (m), or function (f). The term may differ for which language constructs you are going to create your tags.

Jumping into our first tag

Let's open the padrino-core/lib/padrino-core.rb file and place your cursor on server on line 13:

require 'sinatra/base'
require 'padrino-core/version'
require 'padrino-core/support_lite'
require 'padrino-core/application'

require 'padrino-core/caller'
require 'padrino-core/command'
require 'padrino-core/loader'
require 'padrino-core/logger'
require 'padrino-core/mounter'
require 'padrino-core/reloader'
require 'padrino-core/router'
require 'padrino-core/server'
require 'padrino-core/tasks'
require 'padrino-core/module'

# The Padrino environment (falls back to the rack env or finally develop)
PADRINO_ENV  = ENV["PADRINO_ENV"]  ||= ENV["RACK_ENV"] ||= "development"  unless defined?(PADRINO_ENV)
# The Padrino project root path (falls back to the first caller)
PADRINO_ROOT = ENV["PADRINO_ROOT"] ||= File.dirname(Padrino.first_caller) unless defined?(PADRINO_ROOT)

module Padrino
  ...
end

Now press <C-]>- you'll directly to the Server class in the padrino-core/lib/padrino-core/server.rb file. Awesome, that is what you know now what you want to know and you can jump back to your previous position with <C-o> or <C-t>.

You can also jump to the tag you want the command line mode in Vim and use the :tag command. Type in the name of the class or method you want to jump to. For example, if you type in :tag Padrino you will jump to a tag. But you already have a suspicion that Padrino exists in more than one file. You may think this is a mistake but ctags keeps up a list of all the tags you have explored so far.

If you searched after :tag Padrino again you can message line beyond in your command window: tag 1 of 81 or more. There are 81 searchable matchings tags available. Per default Vim will take the first matching tag if your search for the first time in your vim session after :tag Padrino. Use :tselect followed by a number to jump to the tag you want:

  # pri kind tag               file
> 1 F C m    Padrino           padrino-admin/lib/padrino-admin.rb
               module Padrino
  2 F   m    Padrino           padrino-admin/lib/padrino-admin/access_control.rb
               module Padrino
  3 F   m    Padrino           padrino-admin/lib/padrino-admin/generators/actions.rb
               module Padrino
  4 F   m    Padrino           padrino-admin/lib/padrino-admin/generators/admin_app.rb
               module Padrino
  5 F   m    Padrino           padrino-admin/lib/padrino-admin/generators/admin_page.rb
  ...

You can chose what you want to have. There a bunch of more commands you can use to navigate multiple tags:

:tnext (or :tn) - Goes to the next tag in the :tselect list.
:tprev (or :tp) - Goes to the previous tag in the :tselect list.
:tfirst (or :tf) - Goes to the first tag in the :tselect list.
:tlast (or :tl) - Goes to the last tag in the :tselect list.

Before going to add the tags for the Padrino project as well as any other sources you are using on your project, we need to understand how we can get a big tag file of all our installed gems and after that limit our scope to these parts we only need.

Ctag for installed gems

Let's say you are using rbenv to manage your ruby versions and you want to get a global tag file of all your installed gems. Please run the following command:

$ ctags -R -f gems.tag * ~/.rbenv/versions/<your-ruby-version>/lib

I have over 269 installed gems on my system (use gem list | wc -l) and it took around 7 seconds to generate a tag file with over 200.000 lines. The chances are high that you have errors in your tags file occur and I really don't want to load such a big tag file into my vim session. Please note, that the generated tag file gems.tag instead of tags.

Generating Ctags project specific ones gems

If you think about a ruby project, it is very likely that you will have Gemfile with all the specified extensions you need for your project. Andrew Radev has created a ruby snippet that uses Bundler API for retrieving the used Gemfile in your project and builds a tag file. Instead of using the script you can also perform the following one-liner on the route of your application:

ctags -R -f gems.tags `bundle show --paths`

You have a Padrino project (like my Job Vacancy) with the following Gemfile for example:

source 'https://rubygems.org'

# Server requirements
gem 'thin', '1.5.1'

# Project requirements
gem 'rake', '10.0.4'
gem 'uglifier', '2.1.1'
gem 'yui-compressor', '0.9.6'

# Component requirements
gem 'erubis', '~> 2.7.0'
gem 'activerecord', '~> 3.2.9', :require => 'active_record'
gem 'sqlite3', '~> 1.3.6'

# Test requirements
group :test do
  gem 'rspec' , '2.13.0'
  gem 'factory_girl', '4.2.0'
  gem 'rack-test', '0.6.2', :require => 'rack/test'
end

gem 'guard-rspec'
gem 'libnotify'

# Security
gem 'bcrypt-ruby', '3.0.1', :require => 'bcrypt'

# Padrino Stable Gem
gem 'wirble', '0.1.3'
gem 'pry', '0.9.12'
gem 'tilt', '1.3.7'

# Padrino edge
gem 'padrino', :git => "git://github.com/padrino/padrino-framework.git"

bundle show --paths will print the absolute path of the used Gems in the following form:

/home/helex/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/open4-1.3.0
/home/helex/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/bundler/gems/padrino-framework-0c1317b0c897/padrino
/home/helex/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/bundler/gems/padrino-framework-0c1317b0c897/padrino-admin
/home/helex/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/bundler/gems/padrino-framework-0c1317b0c897/padrino-cache
/home/helex/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/bundler/gems/padrino-framework-0c1317b0c897/padrino-core
/home/helex/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/bundler/gems/padrino-framework-0c1317b0c897/padrino-gen
/home/helex/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/bundler/gems/padrino-framework-0c1317b0c897/padrino-helpers
/home/helex/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/bundler/gems/padrino-framework-0c1317b0c897/padrino-mailer
/home/helex/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/bundler/gems/padrino-sprockets-8f4f6150b2d9
/home/helex/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/polyglot-0.3.3
/home/helex/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/pry-0.9.12
/home/helex/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rack-1.5.2

When you start vim in the root of your project, it will only load the tags file but not the gems.tags file. Just open the command line in vim and type in :set tags+=gems.tags.

If you find yourself doing it over and over again for different project, you have to setup the following setting in your .vimrc


set tags=tags,./tags,gems.tags,./gems.tags

Vim will search for the file named tags, starting with the directory of the current file. Since padrino is separated into different parts you want to jump to the parent directory to find the tag files so you have to enable uppward search with the ; symbol at the end of the search term


set tags=./tags;,./gems.tags;

and then recursively to the directory one level above, till it either locates the tags file or reaches the root directory. It will do exactly the same for the gems.tags file.

Autogenerate tags with Autotags.vim

During the coding you are going to change the name of the method or class and have to generate the tags by hand. Do you really want to leave the terminal and generate the tags on your own? Tada, there is Autotags.vim. It deletes all tags that are no longer present and calls ctags -a to append the new tags to your existing tag file. To try it out, create a new directory with the following class definition inside the file:

class Ctags

end

Now create the tags with ctags -R . search after the tag Ctags with :tag Ctags, after that change the class name from Ctags to VimCtags. If this doesn't work for you, it means that you don't have python support enabled for your vim version. You can check it with vim --version | grep python - a +python means that you have it. I have written a blog post about how to install vim with python support for the case you have problems with this.

Fuzzy like tag search with Ctrlp plugin

As we have learned before it is possible that we partially know the name of the class or method name we want to use. This is where you have to use ctrlp.vim plugin. Ones installed, it gives you the :CtrlPTag tag command which make it possible to do a fuzzy like tag search.

If you find yourself using this command very often, you have to add the following mapping into your vimrc:

nnoremap <leader>. :CtrlPTag<cr>

if the Ctrlp doesn't provide you enough hits, please use :tselect.

Writing Zsh Completion for Padrino

2013-07-03T00:00:00+00:00

Learn more about Padrino Book? Sign Up!

I'm a user of the Z shell (zsh). It is easy to customize your prompt and to have more abilities for tab completion of the most used programs with this shell. If you are lazy or new to a new command line tool with a huge amount of options, this will help you in the beginning to remember the commands. When you use [git](http://en.wikipedia.org/wiki/Git_(software) you can press tab to see all available options you have in the current context. The same functions aren't available for Padrino and this is how I came to this article.

Start Small with Basic tmuxinator Completion

Your first step is to create a file with the name of the command for which you want to have autocompletion. The name of the command must begin with an underscore and needs to be in your fpath. The fpath is the variable which will be used for shell searches when the autoload function is first called. Let's enable this feature in your .zshrc:

# folder of all of your autocomplete functions
fpath=($HOME/.zsh-completions $fpath)

# enable autocomplete function
autoload -U compinit
compinit

Before going on, you need to install the tmuxinator gem with:

$ gem install tmuxinator

Let's implement the hello-tmux and version commands for the tmuxinator gem. Inside your ~/.zsh-completions/_tmuxinator file:

#compdef tmuxinator
_tmuxinator() {
  local -a commands
  commands=(
    'hello-tmux:our first autocompletion function.'
    'version:show the used gem version.'
  )

  if (( CURRENT == 2 )); then
    _describe -t commands 'commands' commands
  fi

  return 0
}

_tmuxinator

Now reload your shell with exec zsh and type in $ tmuxinator <Tab>. Voilà, you've written you first autocompletion. I will explain part of the code in the next chapters in case you don't know each detail of the code.

Autocompletion for Padrino

First of all we need to specify the name of the command for which we want to have for Padrino's autocompletion:

#compdef padrino
typeset -A opt_args

Please note, that the first line must be comment with the compdef command followed by the name of the command. With the help of the typeset command we can set and display attributes and values for shell parameters. The -A options says, that names we pass into the autocomplete function refers to associative array parameters. opt_args makes it possible to add command-line options like -d or -f for our associative array.

Next, we are going to define the inputs of our function. We need this to be able to define states in order to get the context in which we are during our completion:

_arguments -C \
  '1:cmd:->cmds' \
  '2:generators:->generator_lists' \
  '*:: :->args' \
&& ret=0

The _arguments function is used to give a complete specification for a command whose arguments follow standard UNIX option and argument conventions. _arguments returns status zero if it was able to add matches and non-zero otherwise. The option -C makes it possible to modify the curcontext parameter. With the help of curcontext it is possible to keep track of the current context. This will be used later in our big state machine like case construct.

1:cmd:->cmds describes the first argument in our completion function. The cmd message will be printed above matches generated and the cmds action indicates what can be completed in this position. Similar, 2:generators:->generator_lists stands for the second argument with the generator_lists option. At last, we need to be able to pass in certain arguments whatever position we are in. For this case we are using *:: :->args. The two colons before any message of the command array indicates that the current context parameter refer only to the normal arguments when the action is evaluated.

Padrino Generators

Everything is set and we need to define Padrino's command for autocompletion. Padrino uses the g option to specify the command for using a generator. After we are in this context we can chose a generator like controller, mailer, migration, model, plugin or project. Depending which generator we take, we can use different, context specific arguments like -a for the mailer generator to create a mailer for the specified sub application or the -d option for defining the orm adapter when using the project generator.

The first argument in Padrino autocompletion, 1:cmd:->cmds, is created with the help of a case statement:

#compdef padrino

typeset -A opt_args

_arguments -C \
  '1:cmd:->cmds' \
  '2:generators:->generator_lists' \
  '*:: :->args' \
&& ret=0


case "$state" in
  (cmds)
     local commands; commands=(
      'g:Padrinos generators'
     )

      _describe -t commands 'command' commands && ret=0
  ;;
ease;

return 1;

Let's go through the parts:

case "$state" - The beginning of our state statement. The $state variable is used for tracking the current state we are in.
local commands - Definition of a variable which is assigned as a list of strings for our completion function. After the name of the command follows the explanation of the command.
_describe -t - The describe functions associates completions with description. All it does is taking our previously defined commands as a list variable commands for zsh compsys function and return 0 to indicate that error occurs. The -t option specify the tag we want to use we want to use in our describe function. In our case we are tagging the local commands for the completions.

Now we know that we are going to use a generator we need to find out which generator want to use in the completion. This is the '2:generators:->generator_lists' part of the _arguments function:

#compdef padrino

typeset -A opt_args

_arguments -C \
  '1:cmd:->cmds' \
  '2:generators:->generator_lists' \
  '*:: :->args' \
&& ret=0

case "$state" in
  (cmds)
     local commands; commands=(
      'g:Padrinos generators'
     )

      _describe -t commands 'command' commands && ret=0
  ;;
  (generator_lists)
    local generators; generators=(
      'controller:creates a new controller'
      'mailer:creates a new mailer'
      'migration:creates a new migration'
      'model:creates a new model'
      'project:create a new Padrino app'
      'plugin:add plugin to your app'
    )
    _describe -t generators 'generator' generators && ret=0
  ;;
esac

return 1

The code above follows nearly the same syntax as the cmds command before. The last thing we need to handle are the optional arguments for each generate state, as defined *:: :->args (imagine this thing as the default or else branch of your control structure):

#compdef padrino

typeset -A opt_args

_arguments -C \
  '1:cmd:->cmds' \
  '2:generators:->generator_lists' \
  '*:: :->args' \
&& ret=0

case "$state" in
  (cmds)
     local commands; commands=(
      'g:Padrinos generators'
     )

      _describe -t commands 'command' commands && ret=0
  ;;
  (generator_lists)
    local generators; generators=(
      'controller:creates a new controller'
      'mailer:creates a new mailer'
      'migration:creates a new migration'
      'model:creates a new model'
      'project:create a new Padrino app'
      'plugin:add plugin to your app'
    )
    _describe -t generators 'generator' generators && ret=0
  ;;
  (args)
    case $line[2] in
      (controller)
        _arguments \
          '-d:remove all generated files' \
          '-n:specify the application' \
          '-r:specify the root'
          ret=0
      ;;
      (mailer)
        local mailers; mailers=(
          '-a:creates a mailer for the specified subapp'
          '-d:removes all generated files'
          '-n:specify the application'
          '-r:specify the root destination path'
        )
        _describe -t mailers 'mailer' mailers && ret=0
      ;;
      ...
      ;;
    esac
  ;;
esac

return 1

If our second inline parameter $line[2] is controller then we have the -d, -n, and -r options. One the other hand if the second inline parameter is mailer the options -a, -d, -n, and -r are available. You can find the whole implementation code under GitHub.

Conclusion

The benefit of writing function completions for zsh is that it is available on nearly every platform. All you need is to have the zsh installed on your machine - there are no other dependencies. Documentation about writing is available but there aren't many practical examples. Look and learn from other how used it and then experiment with it. After some time you'll get the smell how to do it. And please, if you are writing something complex, write a blog post about your completion function to help other getting into it.

Testing Helpers in Padrino

2013-06-06T00:00:00+00:00

Learn more about Padrino Book? Sign Up!

I always was wondering how to test helpers in Padrino and to be honest I postponed this problem for a long time. But this morning I reached the point in my book where I was writing helper with many methods without testing them. When something like this happened you have stop going and spend time to solve this problem.

The Problem

Let's say you have a typical Padrino helper:

# app/helpers/users_helper.rb

JobVacancy::App.helpers do
  def foo
    "bar"
  end
end

You can use the foo method anywhere in you controllers and views. But what happened if your helper is getting more and more complex like the following one:

# app/helpers/users_helper.rb

JobVacancy::App.helpers do
  def current_user=(user)
    @current_user = user
  end

  def current_user
    @current_user ||= User.find_by_id(session[:current_user])
  end

  def current_user?(user)
    user == current_user
  end

  def sign_in(user)
    session[:current_user] = user.id
    self.current_user = user
  end

  def sign_out
    session.delete(:current_user)
  end

  def signed_in?
    !current_user.nil?
  end
end

Right, there is a lot of stuff inside and you need to test this.

Assumption

Let's say you have the following structure within you application:

.
├── app
│   ├── controllers
│   │   ├── ...
│   ├── helpers
│   │   ├── users_helper.rb
│   │   ├── ...
│   ├── models
│       └── ...
├── spec
│   ├── app
│   │   ├── controllers
│   │   │   ├── ...
│   │   ├── helpers
│   │   │   └── users_helper_spec.rb
│   │   ├── models
│   │   │   └── ...
│   ├── spec_helper.rb

And you have written your helper in the typical helper style of Padrino which are generated when you create a new controller:

# app/helpers/users_helper.rb

JobVacancy::App.helpers do
  def foo
    "bar"
  end
end

This syntax is a shortcut for:

helpers = Module.new do
  def foo
    "bar"
  end
end

JobVacancy::App.helpers helpers

In Padrino, helpers are generally an anonymous module. Testing something anonymous isn't possible. To make this helper testable we need to make this module explicit:

# app/helpers/users_helper.rb

module UsersHelper
  def foo
    "bar"
  end
end

JobVacancy::App.helpers UsersHelper

You can still use the foo method everywhere in your views and controller. But now you've got a big plus. You can test it.

Prepare the Spec

We need to require the helper in our spec_helper:

# spec/spec_helper.rb

PADRINO_ENV = 'test' unless defined?(PADRINO_ENV)
require File.expand_path(File.dirname(__FILE__) + "/../config/boot")
require File.dirname(__FILE__) + "/../app/helpers/users_helper" # <--- this is what we need

RSpec.configure do |conf|
  ...
  conf.full_backtrace= false
  conf.color_enabled= true
  conf.formatter = :documentation
end

Write the spec

And here is a spec for that:

# spec/app/helpers/users_helper_spec.rb
require 'spec_helper'

describe UsersHelper do
  before do
    class UsersHelperClass
      include UsersHelper
    end

    @user_helper = UsersHelperClass.new
  end

  it "test foo" do
    @user_helper.foo.should == "bar"
  end

end

We create a class in the before part of the spec which include our UsersHelper module. Next, we are creating the instance variable @user_helper as a new object of our class UsersHelperClass. Running our tests will make unicorns happy and fast:

$ rspec spec/app/helpers

  UsersHelper
    test foo

  Finished in 0.00041 seconds
  1 example, 0 failures

I'm quiet sure that there is a better way to write the spec. If you know a way, please let me know.

Learn more about Padrino Book? Sign Up!

Using Hub for Faster Contributing to GitHub Open-Source Projects

2013-06-04T00:00:00+00:00

Ever wondering how you can easily fork and contribute to an Open-Source project without forking a repository manually in your browser? Then you should have a look into the hub gem.

Hub is a command-line wrapper for git written by defunkt. With it, you can easily create forks of repositories, making pull requests, and get code from other forks with no problems. If you are a maintainer of a very popular repository like twitter bootstrap with over ~23k forks, this tool makes your life a lot easier.

Update: gh is the hub implementation written in Go. It is faster and will be a replacement of the pure hub in the future - thanks @_ZKH for showing me this.

Update: hub is now available as precompiled binaries - so you don't need it compile with go

Installing hub

Grab the latest hub release for your system and player into your bin path.

Workflow to get things done

What I normally do when using Open-Source technologies like the Foundation Framework is trying to give something back. For example by improving documentation, reporting bugs, or solving problems.

First of all let's get the code:


$ hub clone zurb/foundation-sites
  Cloning into 'foundation-sites'...
  remote: Counting objects: 81224, done.
  remote: Compressing objects: 100% (28/28), done.
  remote: Total 81224 (delta 10), reused 0 (delta 0), pack-reused 81195
  Receiving objects: 100% (81224/81224), 112.63 MiB | 1.11 MiB/s, done.
  Resolving deltas: 100% (48423/48423), done.
  Checking connectivity... done.

Now let's make a branch for fixing some documentation issues:

$ git checkout -b readme-fixes

Now you make your changes and run a git commit -m "Fixed documentation" and you are ready to fork the repo:

$ hub fork

Now you need to push the changes to your remote and open a pull request:

$ git push -u wikimatze readme-fixes
$ hub pull-request

That's it. If you want to see a list of open issues, you can use the following command:

$ hub browse -- issues

This will open the issue site in your browser. In our case this would be https://github.com/zurb/foundation-sitesissues.

If you want to see a list of pull-requests, just pass the pulls param

$ hub browse -- pulls

Remember your username and token

Go to your github token settings, generate a fresh one and put them into ~/.config/hub:

---
github.com:
- user: wikimatze
  oauth_token: <TOKEN>

Now you don't need to type in your username and password everytime.

Conclusion

The idea for this blog came out of my first remote paring session with my friend @_ZPH where I wanted to show him this gem but wasn't able to explain him the work flow. So this little snippet is a reminder for him and me.

Using Sprockets to Manage the Asset Pipeline in Padrino

2013-05-23T00:00:00+00:00

Learn more about Padrino Book? Sign Up!

Sprockets are a way to manage serving your assets like CSS, and JavaScript compiling all the different files in one summarized file for each type. They make it easy to take advantage to use a preprocessor to write your assets with Sass, Coffesscript, or LESS.

To implement Sprockets in Padrino there the following strategies:

rake-pipeline - Define filters that transforms directory trees.
grunt - Set a task to compile and manage assets in JavaScript.
sinatra-assetpack - Let's you define you assets transparently in Sinatra.
padrino-sprockets - Integrate sprockets with Padrino in the Rails way.

Padrino Sprockets

First we will create a new Padrino app:

$ padrino g project job-vacancy -d activerecord -t rspec -s jquery -e erb -a sqlite

We are using the padrino-sprockets gem. Let's add it to our Gemfile:

# Gemfile
gem 'padrino-sprockets', :require => ['padrino/sprockets'], :git => 'git://github.com/nightsailer/padrino-sprockets.git'

Next we need to move all our assets from the public folder in the assets folder:

$ cd <path-to-your-padrino-app>
$ mkdir -p app/assets
$ mv public/javascript app/assets
$ mv public/stylesheets app/assets
$ mv public/images app/assets

Now we have to register Padrino-Sprockets in this application:

# app/app.rb
module JobVacancy
  class App < Padrino::Application
    ...
    register Padrino::Sprockets
    sprockets
    ...
  end
end

Next we need to determine the order of the loaded CSS files:

# app/assets/stylesheets/application.css
/*
 * This is a manifest file that'll automatically include all the stylesheets available in this directory
 * and any sub-directories. You're free to add application-wide styles to this file and they'll appear at
 * the top of the compiled file, but it's generally better to create a new file per style scope.
 * require_self: Puts the CSS contained within this file at the precise location (puts this command
 * at the top of the generated css file
 * require_tree . means, that requiring all stylesheets from the current directory.
 *
 *= require_self
 *= require bootstrap
 *= require bootstrap-responsive
 *= require site
*/

First we are loading the bootstrap default CSS, then bootstrap-response, and finally our customized site CSS. The require_self loads the file itself, to define the order that the files are loaded. This is helpful if you want to check the order of the loaded CSS as a comment above your application without ever have to look into the source of it.

Next let's have a look into our JavaScript files:

# app/assets/javascript/application.js

// This is a manifest file that'll be compiled into including all the files listed below.
// Add new JavaScript/Coffee code in separate files in this directory and they'll automatically
// be included in the compiled file accessible from http://example.com/assets/application.js
// It's not advisable to add code directly here, but if you do, it'll appear at the bottom of the
// the compiled file.
//
//= require_tree .

The interesting thing here is the require_tree . option. This option tells Sprockets to include all JavaScript files in the assets folder with no specific order.

Now, we can clean up the include statements in our application template:

# app/views/layouts/application.erb

<!DOCTYPE html>
<html lang="en-US">
<head>
  <title>Job Vacancy - find the best jobs</title>
  <%= stylesheet_link_tag '/assets/application' %>
  <%= javascript_include_tag '/assets/application' %>
</head>

Enable Compression for CSS and JavaScript

Now we want to enable compression for our CSS and JavaScript files. For CSS compression Padrino Sprockets is using YUI compressor and for JS compression the Uglifier. We need to add these these Gems in our Gemfiles:

# Gemfile
...
gem 'padrino-sprockets', :require => 'padrino/sprockets', :git => 'git://github.com/nightsailer/padrino-sprockets.git'
gem 'uglifier', '2.1.1'
gem 'yui-compressor', '0.9.6'

And finally we need to enable minifying in our production environment:

# app/app.rb
module JobVacancy
  class App < Padrino::Application
    ...
    register Padrino::Sprockets
    sprockets :minify => (Padrino.env == :production)
  end
end

Learn more about Padrino Book? Sign Up!

My Talk at Ruby Midwest 2013

2013-05-02T00:00:00+00:00

Here is a picture that explains everything I experienced at this conference:

I received love, motivation, fun, feeling that I'm doing right, passion, energy, and new ideas. But most importantly I made new friends.

The topic of my talk: "We all love Open Source work and Pomodoro will help you to hack on your beloved babies in a time-boxed way to get more done in less time."

Slides

You can find the slides on speakerdeck.

Video

You can find this video on confreaks.

Impressions

Downtown Kansas City.

@kobier from confreaks recording the videos.

Interesting discussions at a roof in the heart of Kansas City.

Ruby Midwest organzisers, Steve Klabnik, Ashe Dryden, and me having lunch.

Some of the Ruby Midwest speakers.

Reward for a speaker - the BBQ sauce is so delicious.

More pictures can be found under flickr Ruby Midwest 2013

Notes

Software: impress.js
Typface:
- FFFTusj
- Lobster Two
Source: Bitbucket

Speaking at Ruby Midwest 2013

2013-02-12T00:00:00+00:00

I received notification that my talk proposal for Ruby Midwest 2013 has been accepted. My talk "More time for Open Source work with the help of the Pomodoro Technique" will show you how you can do more Open Source work besides your day job and other liabilities. I'm very excited, as this will be my first time giving a talk at a conference.

Ruby Midwest 2013 will be held in Kansas City, 5th and 6th of April. Michael Feather and James Edward Grey II are giving keynotes and I will receive the opportunity to meet them. If you attend the conference as well, let us get in touch.

Getting started with RSpec Puppet

2012-09-27T00:00:00+00:00

You never improve if you can't change at all.
Tom DeMarco

Writing your service configuration with Puppet can be easy. But when it comes to debugging, it can be very difficult to edit things and to find certain errors. This article presents your the basic of setting up your environment for testing Puppet modules in a BDD way.

Prevention of bad code with tests.

The tools

The rspec-puppet gem is the Gem setup to get started. It install the rspec-puppet-init command which automatically sets up the basic settings for testing. As a text tool we want to use puppet-lint: This tool checks your Puppet manifests against the Puppet Labs style guide and alert you to any discrepancies => you have now your constant feedback loop when writing code.

Run the following commands to install the gem:

$ gem install rspec-puppet
$ gem install puppet-lint

You can use puppet-lint in your terminal to check a puppet manifest.

$ puppet-lint <path-to-your-manifest>

Let's assume, we have the following puppet file:

# manifests/init.pp
class git::init {
  include git:: package
}

If we run puppet-lint on it:

$ puppet-lint manifests/init.pp
ERROR: two-space soft tabs not used on line 10
WARNING: unquoted resource title on line 10

Setting up the environment

The next step is to clone the puppet boilerplate repository . It's perfect for creating a initial skeleton for a new module. After we get the code, we run a script which guides you through the process of creating a new module:

$ git clone https://github.com/andreashaerter/puppet-boilerplate-modules.git
$ ./puppet-boilerplate-modules/newmodule.sh

Answer the questions in this dialog, that means select the module name, the template for it (0: application-001 is perfect for the beginning), the location, and the author. When your are done with this, go into the directory of your new module and perform the following cleanup commands:

$ cd <your-module-path>
$ rm COPYING CREDITS Modulefile NOTICE README
$ rm -rf files/ templates/

The cleanup is necessary to get you focused on the basics of testing. Now, your file structure should look like the following.

-- manifests
    |-- init.pp
    |-- package.pp
    |-- params.pp

This structure follows the package, config, and service (okay, we have params.pp instead of service.pp but this not bad because the module we create in this example isn't a service) pattern as mentioned by R.I.Pienaar blog post.

The last step is to run rspec-puppet-init in the directory of your module and it will create all the files for testing.

$ cd <your-module-path>
$ rspec-puppet-init
 + spec/
 + spec/classes/
 + spec/defines/
 + spec/functions/
 + spec/hosts/
 + spec/fixtures/
 + spec/fixtures/manifests/
 + spec/fixtures/modules/
 + spec/fixtures/modules/git/
 + spec/fixtures/manifests/site.pp
 + spec/fixtures/modules/git/manifests
 + spec/spec_helper.rb
 + Rakefile

And the file structure should be the following:

|-- manifests
|   |-- init.pp
|   |-- package.pp
|   `-- params.pp
|-- Rakefile
`-- spec
    |-- classes
    |-- defines
    |-- fixtures
    |   |-- manifests
    |   |   `-- site.pp
    |   `-- modules
    |       `-- git
    |           `-- manifests -> ../../../../manifests
    |-- functions
    |-- hosts
    `-- spec_helper.rb

The symlinks in the spec/ directory are linking the manifests folder into your spec folder, so that they are in the runpath of your specs when you run rspec.

Testing, testing, and testing

First, we want to test that the class git::package is created in manifests/init.pp manifests. All we need to do is to create a spec named init_spec.rb in the spec/classes directory. To make it testable, we need to define a scope for our init.pp manifest.

# manifests/init.pp
class git::init {
  class { 'git::package': }
}

Let's do the test for it:

# spec/classes/init_spec.rb
require 'spec_helper'

describe "git::init" do
  it { should create_class('git::packagee')}
end

Remember: Run rake spec always from the root directory of your module!

$ cd <your-module-path>
$ rake spec
/home/helex/.rbenv/versions/1.9.2-p320/bin/ruby -S rspec spec/classes/init_spec.rb

git::init
  should contain Class[git::packagee] (FAILED - 1)

Failures:

  1) git::init
     Failure/Error: it { should create_class('git::packagee')}
       expected that the catalogue would contain Class[git::packagee]
     # ./spec/classes/init_spec.rb:4:in `block (2 levels) in <top (required)>'

Finished in 0.05637 seconds
1 example, 1 failure

Failed examples:

rspec ./spec/classes/init_spec.rb:4 # git::init

Duh, it's red, what should we do? The catalog does not contain a class git::packagee. Gosh, it's a typo in our init_spec.rb file. Let's fix this:

# spec/classes/init_spec.rb
require 'spec_helper'

describe "git::init" do
  it { should create_class('git::package')}
end

And run our tests again:

$ rake spec
/home/helex/.rbenv/versions/1.9.2-p320/bin/ruby -S rspec spec/classes/init_spec.rb

git::init
  should contain Class[git::package]

Finished in 0.03963 seconds
1 example, 0 failures

It's green and running - perfect.

Testing the creation of a package with an attribute

Since we are now sure, that the package manifests is integrated, it's time to write a test, that we have the git-core package in our package manifests. Let's write spec/classes/install_spec.rb:

# spec/classes/package_spec.pp
require 'spec_helper'

describe 'git::package' do

  context 'install git-core' do
    it { should contain_package('git-core')}
  end
end

The contains\_<resource> matcher will test if the manifest contains a particular puppet resource.

And run the tests again with rake spec form the root directory of your module:

$ rake spec
/home/helex/.rbenv/versions/1.9.2-p320/bin/ruby -S rspec spec/classes/package_spec.rb spec/classes/init_spec.rb

git::package
  install git-core
    should contain Package[git-core] (FAILED - 1)

git::init
  should contain Class[git::package]

Failures:

  1) git::package install git-core
     Failure/Error: it { should contain_package('git-core')
       expected that the catalogue would contain Package[git-core]
     # ./spec/classes/package_spec.rb:6:in `block (3 levels) in <top (required)>'

Finished in 0.19843 seconds
2 examples, 1 failure

Failed examples:

rspec ./spec/classes/package_spec.rb:6 # git::package install git-core

Let's edit manifests/package.pp file:

# manifests/package.pp
class git::package {
  package { 'git-core':}
}

And run the tests again:

$ rake spec
/home/helex/.rbenv/versions/1.9.2-p320/bin/ruby -S rspec spec/classes/package_spec.rb spec/classes/init_spec.rb

git::package
  install git-core
    should contain Package[git-core]

git::init
  should contain Class[git::package]

Finished in 0.19894 seconds
2 examples, 0 failures

Next we want to add the ensure attribute to the get the latest version of the git-core package. Let's write a failing test first:

# spec/classes/package_spec.pp
require 'spec_helper'

describe 'git::package' do

  context 'install git-core' do
    it { should contain_package('git-core')
         .with_ensure('latest')
    }
  end
end

The with\_* and without\_* matcher can test the presence or absence of the parameter of resources. Run our tests, to see they are failing:

$ rake spec
/home/helex/.rbenv/versions/1.9.2-p320/bin/ruby -S rspec spec/classes/package_spec.rb spec/classes/init_spec.rb

git::package
  install git-core
    should contain Package[git-core] with ensure => "latest" (FAILED - 1)

git::init
  should contain Class[git::package]

Failures:

  1) git::package install git-core
     Failure/Error: .with_ensure('latest')
       expected that the catalogue would contain Package[git-core] with ensure set to `"latest"` but it is set to `nil` in the catalogue
     # ./spec/classes/package_spec.rb:7:in `block (3 levels) in <top (required)>'

Finished in 0.19862 seconds
2 examples, 1 failure

Failed examples:

rspec ./spec/classes/package_spec.rb:6 # git::package install git-core

Time to fix it:

# manifests/package.pp

class git::package {
  package { 'git-core':
    ensure => latest
  }
}

If we run now our tests again, it should work:

$ rake spec
/home/helex/.rbenv/versions/1.9.2-p320/bin/ruby -S rspec spec/classes/package_spec.rb spec/classes/init_spec.rb

git::package
  install git-core
    should contain Package[git-core] with ensure => "latest"

git::init
  should contain Class[git::package]

Finished in 0.20456 seconds
2 examples, 0 failures

If you have problems with understanding the syntax of RSpec, just checkout the "The RSpec Book" by David Chelimsky.

Refactor

Since we now have green tests, we can play with the code. Let's make manifests.init.pp nicer:

# manifests/init.pp

class git::init {
  # don't like the class declaration syntax: class { 'git::package': }
  include git::package # much better
}

Run the test:

$ rake spec
/home/helex/.rbenv/versions/1.9.2-p320/bin/ruby -S rspec spec/classes/package_spec.rb spec/classes/init_spec.rb

git::package
  install git-core
    should contain Package[git-core] with ensure => "latest"

git::init
  should contain Class[git::package]

Finished in 0.20158 seconds
2 examples, 0 failures

Your catalog is still valid. Have beer because you have written your first tests for puppet and refactored your first manifest.

Conclusion

Testing is important - even or especially with the environment settings for your systems. It take some time to get used to it and you will find it in the beginning very cumbersome to write the code double. But when you are writing 4000 lines of code long manifest you will be happy to have structure, and confidence in your code with your lovely tests.

Checking your HDD

2012-07-12T00:00:00+00:00

Do one thing and do it well.
Unix Philosophy

This article describes a tool for testing your HDD on a daily basis and how can you fill it completely with zeros or random numbers to check it for broken sectors.

I was spending a whole day installing and configuring 4 different operating systems on my new Desktop PC - I didn't use virtualization my Windows because I wanted to use it for gaming (especially Fallout 3). After four weeks the disasters happened: My hard disk drive (HDD)was broken. Before spending a whole installing your new systems, it is worth spending a day to check your new HDD.

Symptoms of a breaking HDD

If you encounter any of the following things you can be sure that your HDD will break soon:

working with Blue Screens and occasionally system fall downs
problems with installing new OS - even on Knoppix
overwriting the hard disk completely
blinking LED even if you are not working - is a sign that the HDD disk is writing the content into still valid sectors

Checking your new HDD with smartools

Smartmontools is an analysis tool for Linux/Unix systems which allows you to check your hard disk - even on your regular usage. The program consists of two parts: smartctl (checking and evaluating HDD parameters) and smartd (is daemon to check your HDD on a regularly state).

Install the tool with the following command:

$ sudo apt-get install smartmontools

Using smartctl for HDD diagnosing

To get an overview of your new HDD please perform:

$ sudo smartctl -A /dev/sda

The -A options says that it will only print the vendor specific informations:

$ sudo smartctl -A /dev/sda
smartctl 6.2 2013-04-20 r3812 [i686-linux-3.11.0-15-generic] (local build)
Copyright (C) 2002-13, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF READ SMART DATA SECTION ===
SMART Attributes Data Structure revision number: 1
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  5 Reallocated_Sector_Ct   0x0033   100   100   010    Pre-fail  Always       -       0
  9 Power_On_Hours          0x0032   099   099   000    Old_age   Always       -       199
 12 Power_Cycle_Count       0x0032   099   099   000    Old_age   Always       -       114
177 Wear_Leveling_Count     0x0013   099   099   000    Pre-fail  Always       -       9
179 Used_Rsvd_Blk_Cnt_Tot   0x0013   100   100   010    Pre-fail  Always       -       0
181 Program_Fail_Cnt_Total  0x0032   100   100   010    Old_age   Always       -       0
182 Erase_Fail_Count_Total  0x0032   100   100   010    Old_age   Always       -       0
183 Runtime_Bad_Block       0x0013   100   100   010    Pre-fail  Always       -       0
187 Uncorrectable_Error_Cnt 0x0032   100   100   000    Old_age   Always       -       0
190 Airflow_Temperature_Cel 0x0032   055   055   000    Old_age   Always       -       45
195 ECC_Error_Rate          0x001a   200   200   000    Old_age   Always       -       0
199 CRC_Error_Count         0x003e   100   100   000    Old_age   Always       -       0
235 POR_Recovery_Count      0x0012   099   099   000    Old_age   Always       -       8
241 Total_LBAs_Written      0x0032   099   099   000    Old_age   Always       -       2076944882

By using the following command

$ sudo smartctl --all /dev/sda

you will get all any information about your hard disk:

$ smartctl --all /dev/sda
smartctl 6.2 2013-04-20 r3812 [i686-linux-3.11.0-15-generic] (local build)
Copyright (C) 2002-13, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Family:     Samsung based SSDs
Device Model:     Samsung SSD 840 PRO Series
Serial Number:    S1ATNEAD710430B
LU WWN Device Id: 5 002538 5503e9703
Firmware Version: DXM05B0Q
User Capacity:    256.060.514.304 bytes [256 GB]
Sector Size:      512 bytes logical/physical
Rotation Rate:    Solid State Device
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   ACS-2, ATA8-ACS T13/1699-D revision 4c
SATA Version is:  SATA 3.1, 6.0 Gb/s (current: 6.0 Gb/s)
Local Time is:    Sat Feb 22 08:38:14 2014 CET
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED

General SMART Values:
Offline data collection status:  (0x00) Offline data collection activity
                    was never started.
                    Auto Offline Data Collection: Disabled.
Self-test execution status:      ( 244) Self-test routine in progress...
                    40% of test remaining.
Total time to complete Offline
data collection:        (53956) seconds.
Offline data collection
capabilities:            (0x53) SMART execute Offline immediate.
                    Auto Offline data collection on/off support.
                    Suspend Offline collection upon new
                    command.
                    No Offline surface scan supported.
                    Self-test supported.
                    No Conveyance Self-test supported.
                    Selective Self-test supported.
SMART capabilities:            (0x0003) Saves SMART data before entering
                    power-saving mode.
                    Supports SMART auto save timer.
Error logging capability:        (0x01) Error logging supported.
                    General Purpose Logging supported.
Short self-test routine
recommended polling time:    (   2) minutes.
Extended self-test routine
recommended polling time:    (  20) minutes.
SCT capabilities:          (0x003d) SCT Status supported.
                    SCT Error Recovery Control supported.
                    SCT Feature Control supported.
                    SCT Data Table supported.

SMART Attributes Data Structure revision number: 1
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  5 Reallocated_Sector_Ct   0x0033   100   100   010    Pre-fail  Always       -       0
  9 Power_On_Hours          0x0032   099   099   000    Old_age   Always       -       199
 12 Power_Cycle_Count       0x0032   099   099   000    Old_age   Always       -       114
177 Wear_Leveling_Count     0x0013   099   099   000    Pre-fail  Always       -       9
179 Used_Rsvd_Blk_Cnt_Tot   0x0013   100   100   010    Pre-fail  Always       -       0
181 Program_Fail_Cnt_Total  0x0032   100   100   010    Old_age   Always       -       0
182 Erase_Fail_Count_Total  0x0032   100   100   010    Old_age   Always       -       0
183 Runtime_Bad_Block       0x0013   100   100   010    Pre-fail  Always       -       0
187 Uncorrectable_Error_Cnt 0x0032   100   100   000    Old_age   Always       -       0
190 Airflow_Temperature_Cel 0x0032   055   055   000    Old_age   Always       -       45
195 ECC_Error_Rate          0x001a   200   200   000    Old_age   Always       -       0
199 CRC_Error_Count         0x003e   100   100   000    Old_age   Always       -       0
235 POR_Recovery_Count      0x0012   099   099   000    Old_age   Always       -       8
241 Total_LBAs_Written      0x0032   099   099   000    Old_age   Always       -       2077259002

SMART Error Log Version: 1
No Errors Logged

SMART Self-test log structure revision number 1
No self-tests have been logged.  [To run self-tests, use: smartctl -t]


SMART Selective self-test log data structure revision number 1
 SPAN    MIN_LBA    MAX_LBA  CURRENT_TEST_STATUS
    1          0          0  Not_testing
    2          0          0  Not_testing
    3          0          0  Not_testing
    4          0          0  Not_testing
    5          0          0  Not_testing
  255  203828736  203894271  Read_scanning was never started
Selective self-test flags (0x0):
  After scanning selected spans, do NOT read-scan remainder of disk.
If Selective self-test is pending on power-up, resume after 0 minute delay.

Important of the output is the parameter "PASSED", it tells you that the test is over. You can perform longer tests of your hard disk with:

$ sudo smartctl -t long /dev/sda

Depending on the size of your HDD, it takes some time. For checking a whole 500 GB the program runs about 80 minutes. It is even possible to check if your HDD has damage incurred during transporting the drive with the conveyance option:

$ sudo smartctl -t conveyance /dev/sda

Performing long time diagnostic with smartd

The first step is to give the daemon the permission to run checks in the background:

$ vim /etc/default/smartmontools
> start_smartd=yes

Find the line with and uncomment it:

# uncomment to start smartd on system startup
# start_smartd=yes

The configuration file for the daemon can be found under /etc/smartd.conf. Here only one line is sufficient to check all HDDs:

DEVICESCAN -m matthias@wikimatze.de -M exec /usr/share/smartmontools/smartd-runner

Let's get through each line step-by-step:

DEVICESCAN: will scan all HDDs in the range between /dev/hd[a-I] .. /dev/sd[a-z], which support SMART
-m matthias@wikimatze.de: in case of an error, an email will be sent to this address
-M: the frequency of emails departure
- -M exec: don't send testmails
- -M test: send a testmail (when using this option, you must leave out the /usr/share/smartmontools/smartd-runner)
- -M daily: send daily reports Now it's time to test our configuration: bash $ smartd -q onecheck

You can check your internal mails with $ sudo mail (you need install Postfix on your OS) and rebooting the daemon:

/etc/init.d/smartmontools restart

If you want to have a graphical client for this tool, you need to run:

$ sudo apt-get install gsmartcontrol

You need then to start the program in sudo mode to detect all HDDs sudo gsmartcontrol.

Checking the whole space on your HDD

You know these tiny small dd commands? No, it's time to learn and understand them. They are very handy to fill your your whole HDD with lovely zeros and ones.

dd stands for data definition. It has direct access on the hard disk and can read boot sectors - it is even used to create iso files of CDs.

Writing zeros or random numbers

$ dd if=/dev/zero of=/dev/sda

Take from the input file (if) the zeros (/dev/zero) and write them on the output file (of) /dev/sda. If the command has written the whole hard disk, it will end.

Speeding up the process with faster writing

Normally, each block of the hard disk has the size of 512 KB. To set the blocksize on 1 MB (1024 KB), we can speed up the writing speed with the factor two. We can achieve do this with the bs option.

$ dd if=/dev/zero of=/dev/sda bs=1024

Jump over errors

dd will end, if it detects a broken sector. With the conv=noerror option, dd will write till the HDD is full even over broken sectors:

$ dd if=/dev/zero conv=noerror of=/dev/sda bs=1024

Other useful parameters are notrunc (write the output file completely) or sync (write with the full length).

Running the dd command with status display

We can use the pv command to monitor the progress of data through a pipe. First we need to install it:

$ sudo apt-get install pv

To get an overview about how many MB or GB have already be written, use the following command:

$ dd if=/dev/random conv=notrunc,sync bs=1024 | pv > /dev/sda

Conclusion

A broken HDD is a bad thing, but if you know the symptoms it saves you a lot of time because you you know that you have to buy new hardware. Always have backup on an external HDD to have a save data replacement.

It is good to run a couple of tests before you start implementing your whole system.

Creation of a Ruby Gem

2012-06-07T00:00:00+00:00

Everything should be made as simple as possible, but not simple.
Albert Einstein

This article describes the crafting of a Ruby gem.

The situation: For Jekyll I wanted to get an overview of how many pages, links, when the last build was, how many images I used in my blog, and when I lastly updated my Bitbucket repositories. But before we dive deep into the creation, I will explain what a gem is and how you get started with writing your own gem. Don't be afraid if you are writing a gem that already exists, your goal is to learn how to write a gem.

Ruby Gem

A Ruby gem is a self contained Ruby application which is packed as software. It can be downloaded and then used in other programs. Gems extends the core Ruby language through functions that are commonly used and may be of usage by other programmers. Many gems provides command line operations and help to automate tasks. Not all gems needs to contain a binary, like my sweetie gem.

Basic structure of a Gem

Below is a typical structure of gem:

.
├── README.md
├── Rakefile
├── lib
│   ├── sweetie
│   │   ├── bitbucket.rb
│   │   ├── conversion.rb
│   │   └── helper.rb
│   │   ...
│   └── sweetie.rb
│   ...
├── spec
│   ├── sweetie_bitbucket_spec.rb
│   └── sweetie_conversion_spec.rb
│   ...
└── sweetie.gemspec

A typical gem consists of the main class file (like sweetie.rb). This file contains other ruby-files (normally a list of require statements). The README.md briefly explains what the gem does, how to install it, explains the license, and should include small use cases for the gem (please checkout the README of the sweetie gem to see what I mean). The sweetie.gemspec file contains meta-information like who invented the gem, declare runtime environment dependencies, etc. A gem should have test-files, that other people can contribute to the Gem without damaging the main functionality.

Gemfile structure

First of all we create a Gemfile which defines important informations for the rubygems.org website. The site shows the author, the sources, the homepage, and some statistics (e.g. how often the gem was installed) - and by the way, it's a nice place to sniff in the code of other hackers.

Here is an example sweetie.gemspec:

$:.push File.expand_path("../lib", __FILE__)
require 'sweetie/version'

Gem::Specification.new do |s|
  s.name             = 'sweetie'
  s.version          = Sweetie::VERSION
  s.date             = '2012-06-05'
  s.authors          = ['Matthias Guenther']
  s.email            = 'matthias.guenther@wikimatze.de'
  s.homepage         = 'https://github.com/wikimatze/sweetie'

  s.summary          = %q{Be short and precice!}
  s.description      = %q{Here you can write more and describe detailed features!}

  s.files            = `git ls-files`.split("\n")
  s.test_files       = `git ls-files -- {test,spec,features}/*`.split("\n")
  s.require_paths    = ["lib"]

  s.extra_rdoc_files = ["README.md"]

  s.add_runtime_dependency 'nokogiri', ">= 1.4.6"
  s.add_runtime_dependency 'json', ">= 1.6.1"
  s.add_development_dependency 'rake'
  s.add_development_dependency 'rspec'
  s.add_development_dependency 'yard'
end

Let's explain the stuff which aren't obvious:

$:.push - magic line that ensures "../lib" is in the load path
require 'sweetie/version' - we need this line, because the module sweetie/version.rb contains the version number of the gem
s.files - uses a clever git command which lists all files under version-control - these files are directly included in the gem
s.test_files - again, a clever git listing command with ruby's split() method - files that are used for testing the gem (the line supports TestUnit, MiniTest, Machinist, RSpec, Cucumber, and others
s.require_paths - these paths will be added to $LOAD_PATH when the gem is activated
s.summary - short summary of the gem's description => will be displayed when running gem list -d
s.description - a long description of this gem => it goes more into detail than s.summary
s.extra_rdoc_files - here you can add files which can be used for the RubyDoc site - here the .gemspec README.md is the "main homepage" of the generated documentation
s.add_runtime_dependency - additional gems that will be installed when using this gem
s.add_development_dependency - additional gems needed when hacking on the gem (e.g. Rake is used for building and deploying the gem)

Building and Installing the Gem

Once you have created some code (it doesn't matter how small the code is, except it must be valid and tested ruby code), you should build it on your local machine before making it public:

$ gem build sweetie.gemspec
=> Successfully built RubyGem
  Name: sweetie
  Version: 1.0.0
  File: sweetie-1.0.0.gem

Now you can install the gem locally:

$ gem install sweetie-1.0.0.gem

And test the installation with:

$ gem list | grep sweetie
$ irb
>> require 'sweetie'
=> true

It's working and you can experiment with the script locally.

Publishing your gem

First, you need to register on rubygems.org. After that you can push the gem there with one simple command:

gem push sweetie-1.0.0.gem
Pushing gem to RubyGems.org...
Successfully registered gem: sweetie (1.0.0)

If you want to check if your gem is online, the console is your friend:

gem list -r sweetie

...

sweetie (1.0.0)

This will print all the gems which fit to the specified gem.

Conclusion

It is easy to write an gem for ruby. Start small, create a repository on GitHub get something similar to hello world running, test your code with , and create a briefly documentation (read Zach Holman documentation talk to see why) about what the gem does, and give small examples. After this test your gem, deploy it on rubygems.org and spread the word about your accomplished on twitter - time to drink a beer!

Searching Haml files with ack

2012-05-14T00:00:00+00:00

This article describes how you can configure your ack settings to search for additionals files. UPATE: Andy Lester, the author of ack, give me feedback about this article.

Recently I was working on a Rails project and was using Vim with the :Ack <pattern> command to search after a certain typed string "Übreschrift" and would like to replace it with the correct version "Überschrift". I typed into the console :Ack Übreschrift and I couldn't find a single match. What went wrong?

Questions to answer

Why couldn't I find the file with that content? Was I in the wrong directory? No:

$ pwd
-> $HOME/git-repositories/brokenlifts

Did I used the wrong pattern? No, I searched after the right word "Übreschrift". Did I used the wrong command? No, I tried ack-grep in the terminal to search for other common words like test or string and could only find results in .rb, *.js files but not in `.html.hamlfiles. Tada, found the mistake,ackis per default not configured to include these very special file types. If your pressack -f(thanks [Andy Lester](http://petdance.com/) for this note) you will get the output of all files ack will go through - and this command didn't displayed*.html.haml` files.

Solve problems .ackrc

I created the $HOME/.ackrc and added the entries to include these special filename:

--type-add
html=.html.haml

Now my search worked and I got hits in *.html.haml files for searching the term "Übreschrift".

Further refinements

Since I'm working with Rails there are other file types like sass, erb, less, scss, .. I would like to include into the search:

--type-add
html=.html.erb,.html.haml,.haml
--type-add
css=.sass,.less,.scss

And there might be directories I don't want to have in my search path. Let's ignore them and speed up our search:

# ignore certain file types
--type-set=ignorables=.log,.tmp,.pdf

# ignore whole directories
--ignore-dir=vendor
--ignore-dir=log
--ignore-dir=tmp
--ignore-dir=doc
--ignore-dir=coverage

If you would like to see the specified files for your grep environment search, use ack --help types - this will print all information you need. Here is an example:

$ ack --help types
=>
  --[no]actionscript .as .mxml
  --[no]ada          .ada .adb .ads
  --[no]asm          .asm .s
  --[no]batch        .bat .cmd
  --[no]binary       Binary files, as defined by Perl's -B op (default: off)
  --[no]cc           .c .h .xs
  --[no]cfmx         .cfc .cfm .cfml
  --[no]cpp          .cpp .cc .cxx .m .hpp .hh .h .hxx
  --[no]csharp       .cs
  --[no]css          .css .sass .less .scss
  --[no]elisp        .el
  --[no]erlang       .erl .hrl
  --[no]fortran      .f .f77 .f90 .f95 .f03 .for .ftn .fpp
  --[no]haskell      .hs .lhs
  --[no]hh           .h
  --[no]html         .htm .html .shtml .xhtml .html.erb .html.haml .haml
  --[no]ignorables   .log .tmp .pdf
...

Installing PostgreSQL gem under Ubuntu and Mac

2012-02-26T00:00:00+00:00

This article describes how to install the postgresql gem (called 'pg') under your local machine. The installation process is not trivial because you need to install the right packages under Ubuntu/Linux or set the specify the correct path for Mac.

I checked out a new rails app called Brokenlifts. Brokenlifts in public transportation are annoying and limit the mobility of people in wheelchairs. The app provides status information from different operators on one page and shows how well they are performing.

Ones I checked out the project I have detected that it uses PostgreSQL as their database driver. I have never worked with it and I run into a couple of problems to get it running.

The problem

A $ gem install pg brought me the following error message:

$ gem install pg
Building native extensions.  This could take a while...
/Users/helex/.rbenv/versions/1.9.2-p290/lib/ruby/site_ruby/1.9.1/rubygems/ext/builder.rb:48: warning: Insecure world writable dir /Users/helex/bin in PATH, mode 040777
ERROR:  Error installing pg:
    ERROR: Failed to build gem native extension.

        /Users/helex/.rbenv/versions/1.9.2-p290/bin/ruby extconf.rb
checking for pg_config... no
No pg_config... trying anyway. If building fails, please try again with
 --with-pg-config=/path/to/pg_config
checking for libpq-fe.h... no
Can't find the 'libpq-fe.h header
\*\*\* extconf.rb failed \*\*\*
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers.  Check the mkmf.log file for more
details.  You may need configuration options.

Provided configuration options:
  --with-opt-dir
  --without-opt-dir
  --with-opt-include
  --without-opt-include=${opt-dir}/include
  --with-opt-lib
  --without-opt-lib=${opt-dir}/lib
  --with-make-prog
  --without-make-prog
  --srcdir=.
  --curdir
  --ruby=/Users/helex/.rbenv/versions/1.9.2-p290/bin/ruby
  --with-pg
  --without-pg
  --with-pg-dir
  --without-pg-dir
  --with-pg-include
  --without-pg-include=${pg-dir}/include
  --with-pg-lib
  --without-pg-lib=${pg-dir}/lib
  --with-pg-config
  --without-pg-config
  --with-pg_config
  --without-pg_config


Gem files will remain installed in /Users/helex/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/pg-0.13.2 for inspection.
Results logged to /Users/helex/.rbenv/versions/1.9.2-p290/lib/ruby/gems/1.9.1/gems/pg-0.13.2/ext/gem_make.out

What relevant about the mess up there is the following part:

checking for pg_config... no
No pg_config... trying anyway. If building fails, please try again with
 --with-pg-config=/path/to/pg_config
checking for libpq-fe.h... no

Ruby can't find the relevant setting of the PostgreSQL installation. Let's change this!

Solution for Mac

install PostgreSQL library as described on the PostgreSQL page (opening the *.dmg file will install a bunch of stuff, so don't be afraid of the amount of steps you have to perform)
check if you can find the installation open it under /Library/PostgreSQL/x.y - where x.y stands for the version you installed

Say you want to install the PostgreSQL manually with a gem install - you have to perform the following command:

$ sudo PATH=$PATH:/Library/PostgreSQL/x.y/bin gem install pg

If you want to install it with Bundle, run the following command

$ sudo PATH=$PATH:/Library/PostgreSQL/x.y/bin bundle install

Please change the x.y with the version you have installed. Thats it!

If you have problems with gcc, please look into the stackoverflow link - thanks Asad.

Solution for Ubuntu/Linux

It is easier because you only have to install the right packages:

sudo apt-get install postgresql
sudo apt-get install libpq-dev

Now gem install pg should work.

Conclusion

It can be a really pain if you want to install gems and don't have the right dependencies on your machine but if you initially invest some time on the problem, you have your enlightenment.

Compiling Vim from source for Ubuntu and Mac with ruby and python support

2012-02-19T00:00:00+00:00

This article describes how to build Vim (vim and gvim) from the source and compile it against a predefined version of ruby installed with rbenv. In the first chapter I'm describing how to build it from source for Ubuntu. The second part describes how to build for MacVim.

By installing Vim with ruby support from the sources, it is build against the system wide installation of ruby. If you already installed Vim and/or ruby with sudo apt-get install vim (or sudo apt-get install ruby) or with brew install vim (e.g. brew install ruby) if you are using OS X, remove it completely from your system to install the latest version of Vim.

Install rbenv

I'm installing rbenv on different machines I created the following script (named rbenv_install.sh) to install ruby 1.9.2-p320:

cd $HOME
sudo rm -rf .rbenv
git clone git://github.com/sstephenson/rbenv.git .rbenv
echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bash_profile

# install steps for rbenv-install command
cd $HOME/Downloads
sudo rm -rf ruby-build
git clone git://github.com/sstephenson/ruby-build.git
cd ruby-build
sudo bash install.sh

# updating the current shell
cd $HOME
exec $SHELL
source $HOME/.bash_profile

rbenv-install 1.9.2-p290
rbenv rehash
exec $SHELL

After this try the following:

$ rbenv global 1.9.2-p320
$ rbenv local 1.9.2-p320
$ ruby -v
=> ruby 1.9.2p320 (2012-04-20 revision 35421) [i686-linux]

Get the latest version of Python

This will be put in the $HOME/lib folder:

cd /tmp
wget http://www.python.org/ftp/python/2.7.3/Python-2.7.3.tar.bz2
tar xjvf Python-2.7.3.tar.bz2
cd Python-2.7.3
./configure --prefix=$HOME
make && make install
make inclinstall
hash -r

# cleanup
cd /tmp && rm -rf Python-2.7.3

Get the latest version of Vim

Visit vim.org and select the right download for your operation system (mainly Unix). If you are using a Unix system yo can get the latest Vim from here, download and unzip it:

$ cd $HOME/Downloads
$ wget ftp://ftp.vim.org/pub/vim/unix/vim-7.4.tar.bz2
$ tar -xjvf vim-7.4.tar.bz2

You can also get the latest Vim version from the git repository https://github.com/b4winckler/vim and checkout the latest tag you want to have.

Compiling Vim and Gvim

To install Gvim on Ubuntu we need to install additional packages on our machine. The following snippets describe the packages for Ubuntu:

$ sudo apt-get install libncurses-dev libgnome2-dev \
 libgtk2.0-dev libatk1.0-dev libbonoboui2-dev libcairo2-dev \
 libx11-dev libxpm-dev libxt-dev

Next, we need to configure the compilation and make the install:

cd ~/git-repositories/vim && git checkout v7-4-183 && git clean -f

./configure --prefix=/usr/local \
  --without-x \
  --disable-nls \
  --enable-gui=no \
  --enable-multibyte \
  --enable-rubyinterp \
  --enable-luainterp \
  --enable-pythoninterp \
  --with-python-config-dir=$HOME/lib/python2.7/config \
  --enable-gui=gnome2 \
  --with-features=huge \
  --with-tlib=ncurses \

sudo make && sudo make install && sudo make clean

Let's get over the heavy stuff:

--prefix=/usr/local - place of the binaries of the installed Vim installation (check the /usr/local/bin) - there will be the executable binaries
--enable-rubyinterp - says you want to build Vim with the default ruby installation (in our case /home/mg/.rbenv/shims/ruby)
--enable-gui=gnome2 - building Vim with Gvim support (if you don't want Gvim than you can leave this line out)

After configuring the compilation check if the console response contains the following terms:

checking --with-ruby-command argument... defaulting to ruby
checking for ruby... (cached) /home/mg/.rbenv/shims/ruby
checking Ruby version... OK
checking Ruby header files... /home/mg/.rbenv/versions/1.9.2-p320/include/ruby-1.9.1

If you can't see the lovely Ok, your Vim compilation will probably not have ruby support. Maybe you have not installed ruby the right way or some packages are missing on your machine.

Check the installation

Open a new session or perform exec $SHELL to reboot your Shell. You will see the fresh installed version of Vim:

$ which vim
/usr/local/bin/vim

$ which gvim
/usr/local/bin/gvim

Next check is to get the correct --version of vim and gvim with the following commands:

$ vim --version | ack ruby
$ vim --version | ack python
$ gvim --version | ack ruby
$ gvim --version | ack python

If both commands return +ruby and +python, you are fine, and got the achievement "I installed vim form source with ruby support on my own". You should now be able to run the Hammer.vim plugin - install it, start it with :Hammer, install the missing gems and if you are able to run :Hammer without any missing dependencies, you have setup everything correct.

Installing MacVim from source

The ways are nearly the same as mentioned above: Install rbenv as mentioned in the steps before.

$ cd $HOME/Download
$ git clone git://github.com/b4winckler/macvim.git

Next step is to configure MacVim for OSX:

$ cd macvim/src
$ ./configure --prefix=/usr/local \
              --with-features=huge \
              --enable-rubyinterp \
              --enable-pythoninterp \
              --enable-perlinterp \
              --enable-cscope

After configuring the compilation check the console response after the following terms:

checking --with-ruby-command argument... defaulting to ruby
checking for ruby... /Users/helex/.rbenv/shims/ruby
checking Ruby version... OK
checking Ruby header files... /Users/helex/.rbenv/versions/1.9.2-p320/include/ruby-1.9.1

When this is finished, it is time build MacVim with make:

$ make

Next step is to run the MacVim installation:

open MacVim/build/Release/MacVim.app

The window should open MacVim. Run the following command in the MacVim quickfix window:

:ruby puts "MacVim"

In the next step, you can drop the MacVim.app icon in your Application folder and you are done.

Conclusion

It was a pain to gather the information for building vim by source with rbenv. Duration of finding that was: ~ 6 h. I'm not sure if all of this works on RVM - I just need additional feedback from people using it. Happy "Vim-ing"!

SMART principle

2012-01-12T00:00:00+00:00

This post is about the SMART principle that helps you to start and keep rolling projects. I outlined how I use SMART for my eBook project.

I recently read the book Pragmatic Programmer, in which Dave Thomas explained the SMART principle. SMART is an acronym and each character of the principle has the following meaning:

S (specific goal): What is the goal of the new project you want to start.
M (measurable): List all the features you need to accomplish to start the project.
A (action): When will you start.
R (realistic): Is the project small enough to finish it in the specified time frame demanded time frame.
T (time): In the beginning of July 2012 everything should be fine.

Putting theory into practice

Late in 2011, I started a new and personally ambitious project: Writing an eBook about the great web framework Padrino. In a first step, I created a rough road map, about what I wanted to write and which topics should be covered. After writing the intro section and pushing the resources to GitHub I did something very crazy and mentioned @padrinorb in one of my tweets and this was it -- the authors of the framework motivated me with with writing the book. They retweeted every small progress I made with the project and through that I got further pull requests and even a bunch of interested followers who are watching the project.

Beginning of something great

Let's see how I can formulate the Book project with SMART:

S (specific goal) - I want to learn how to write a eBook easily about Padrino web framework
M (measurable)
- create a roadmap about the topics of the book
- find a method to write book in one format and export the as PDF, EPUB, MOBI, and HTML format
- get really involved in Open source community and communicate with them
- find an audience and get help from other people
A (action)
- start as soon as possible
- try to write everyday one chapter of the book
- tweet about the progress I made everyday
R (realistic)
- it is a big project (never have written a book before) but continuously delivery will motivate me during this long period
T (time)
- till February 2012 everything should be finished

I set up the frame of SMART goals and developed a rough plan - that's all you need to let come your dreams true.

The SMART principle was first mentioned in 1981 as an issue of Management Review by George T. Doran.

Cost for SMART

To be honest, writing of my Padrino eBook project consumes a lot of my free time so I in the near future I will publish only a few new entries on this blog. I have many ideas and topics I want to cover, but first I will finish this book to deepen my writing experience. I'm glad to hear your opinion (or contribution) to the book - I will put every contributer on the special thanks list of the book.

Conclusion

SMART is great if you want to start in small steps to begin with something completely new, learn much about it, and report (for example, I'm using the twitter Hashtag #dailywriting, #padrinobook) about the progress you made.

Thanks to Sebastian Guenther for reading an earlier draft of this post.

Global Coderetreat 2011 in Berlin

2011-12-04T00:00:00+00:00

I attended the Global Coderetreat event initialized by Corey Haines. The general purpose of this event was to get a bunch of hackers together to implement Conway's Game of Life.

Setting up goals

As J. B. Rainsberger mentioned in his article four elements of simple design, it is best to setup goals for your retreat to get most out of it. Here is a list of what I achieved in each session:

Being a mentor of TDD: I taught dedan how to use TDD, why TDD helps you to think about your design.
Being a mentor of BDD: Showing a fellow Rubyist how to do BDD.
Doing something completely stupid: I played evil coder and ping-pong pairing with @tilosoenke - we couldn't communicate with words, only with code, one writing tests and other the implementation of the tests.
Discuss about names: We said together and discussed about right names for methods, variables, and classes. We concluded that good names saves you scary comments in your code.
Explain Ruby to a Java-Programmer.
Being mentored about Lisp: We solved the whole 'Game of Live' in common Lisp , while @HansHuebener explained me the strength and beauty Common Lisp.

Conclusion

It was great to get so many people with so many different skills and mindsets together, exchange experience and encouraging others to try something new. I will definitely have a closer look on Lisp to enhance my Ruby programming style.

Thanks to Sebastian Guenther for reading an earlier draft of this post.

Benefits of Scala

2011-10-29T00:00:00+00:00

When a new programming language is created, it came from a desire of one person or a group of to do it better than their forerunner. It's an evolutionary process that humans are trying to improve themselves if something doesn't as they want it to. Sometimes it's only a small piece of improvement which creates an absolutely new feeling about something. By designing a new programming language you have a great pool of existing languages: LISP (1958), Smalltalk (1970), C++ (1979), Python (1991) and Ruby (1995). Today it is often told not to waste your time on building up an new language from the scratch. It's time-consuming and why should you invent the wheel a second time? I think this is normal. If you spend some time reading about the languages mentioned above, you will see that older language have still a great influence on new ones. Today, it is common to use DSLs (they are used extensively in Rails) to create new languages. Not everything happened in the past was bad and sometimes if you stick your head into some old forgotten technology you may find some diamonds.

This was the main idea of Odersky when he created Scala. It is the first language which is a real hybrid language and combines the invigorations of OOP and FP.

Facts about Scala

Scala is ideal for today's scalable, distributed, component-based applications that support concurrency and distribution.
Scala is statically typed that means that the type of some variable is immutable during the whole execution of the program.
There is modular mixin-composition for classes - some hack to enable multiple inheritance in Scala, which solves the diamond problem through linearity of the inheritance hierarchy via traits.
Support of functions that may have other functions as arguments which enables using anonymous functions.
Lower risk to use Scala in an existing Java Application because Scala works seamless with existing Java Code.
high level type system with variance annotations, compound types, lower and upper bounds for types
usage of inner and anonymous classes
implicit conversions - that means a function take one type as an argument and returns to another type (like converting an Integer into String)

Conclusion

Scala is a very rich language which combines many features of different languages. It's great if you have to make different sections of your code cleaner, faster and conciser. See Scala at LinkedIn to know what I mean.

Thanks to Hanna Schütt and Sebastian Gerth for reading an earlier draft of this post.

Mail Client in Java

2011-10-22T00:00:00+00:00

Most people spend more time and energy going around problems than trying to solve them.
Henry Ford

During the summer term 2007 we had the task to create a Thunderbird like email client Java. The GUI should be created either with Swing or AWT. Beside the graphical implementation, we had to check and study the functionality of POP3 and SMTP. Only the correct numbers in this protocols are important because they stands for each transactions if it was a success or a failure. A first attempt this functionality was done with plain old sockets to get a feeling how POP3 and SMTP works.

After we a running function the basic functions of the mail client, we had to implement some extra-functions like attachments (mime parts in an email) or the handling of emails with drag-and-drop. I implemented this big project with the help of NetBeans IDE.

Images

By means of the following images I will describe the basic layout of my email client.

The basic surface when the program starts. If you press on the upper task bar a drag-and-drop menu will open.

In this window you can add data of a new account.

Get the mail of an already existing account.

The window where to write a new email.

Drag-and-Drop window to manage emails.

Installation for NetBeans

get the sources from github
extract the javamail-1.4.zip => this package contains a Java library for handling emails
create a new project under NetBeans and copy all files of the Mail Client directory in the src directory of you NetBeans project
then you have to insert the mail.jar file in your project in the following way:
- click right on Libraries in the near of the view of your NetBeans project and chose Add JAR
- navigate to javamail-1.4 folder and select the mail.jar
- when you now select the files GUIMailsend.java and GUIMailsget.java should not show any errors
now you have to adopt the paths in the file GUIMain.java (static File f, String dir, FileReader file) and GUITree (File driveC, File source, File ziel) to your NetBeans project folder through absolute paths => I know it's cumbersome but due to this date I couldn't do any other
set the GuiMain.java as the main file in your project and start the program
the standard account is MG kontoinfos.kondat which contains the necessary data to access my spam account (you can guess how to change the data)
the directory Inbox MG saves all read mails of the user MG, further accounts have to be created each in an own directory
MailApi.java is not necessary for the mail client, this will be used to check the correctness of the POP3 settings via the terminal
main cause of error messages:
- wrong paths to your project
- POP3 and SMTP
- mail.jar is not included correct in the project, but this will be shown in NetBeans

Conclusion

This project was my first big piece of software and I used all my gathered knowledge about Java. The classes are not bug-free, manually tested, has a size over 1000 LOCs, has absolute paths, and the function are sometimes very big. In the end it was just hacking down the software without using certain patterns or careful development with clean code. I tested my code with System.out.println and I lost much time with this stupid testing. One good thing I did: I created comments and was able to get the program running even after two year.

Nowadays programming methodologies like Agile, Rapid-Prototyping or Model-Driven development together with the framework Rails let you develop my application with much more less effort and is more maintainable by driving the Test-Driven way- you can refactor your code and don't need to manual test part of your basis if you have tests available.

This project shows that it is possible to develop modular software in Java but in even greater projects it is easy to get lost in the lost in Java code if you don't rely on a framework.

Benefits of reading a book - and use it right after that

2011-10-15T00:00:00+00:00

We are what we repeatedly do. Excellence, then, is not an act, but a habit.
Aristotle

It's a typical situation which every person knows: You look on your workspace and have a bunch of new books there. You ordered them because some great guys lay their hands in the fire that you need this wisdom. You have to do a stressful job and don't have time to read all the things but you still must learn new things in order to develop new skills. What should you do? The simple answer is start reading!

What you should do during the process of reading

Don't read books and put it away, read trough the table of contents, mark the parts which are interesting for you and draw a mind map. If you have questions which should be answered by the book, it's good because then you will read the book with much more focus on them.

Don't think of reading the book like in school: Cram for a test about it, get a good grade and then forget everything. This isn't good and a waste of time. Don't say you don't have time, think of allocating your time effective. For me it's the best, to use the new knowledge out of the book. This is the best way to get the most out of it. What you're right using is just as good as cooking a new meal right after reading the recipe of it. You inherit the procedure you recently learned with your own mind, own feelings, own observations and add your own style (think of your own ingredients in your favorite meal).

Benefits of note taking

Years after reading the book you will maybe come in the situation where you need some of the knowledge you have read of this certain book you read it a lot of years ago. You know the title of the book but can't remember anything. Before I explain the advantage of taking notes during reading a book, I suggest you my different methods for taking notes:

a pencil and a sheet of paper (which I personal prefer)
Netbook/iPad/cellphone (there you can directly take your notes)
you can use post-it or stick it to mark important passages
speaking notes of certain passages which you find very interesting
read an eBook with your kindle, iPhone or some other devices in which you can take custom-notes about something

The disadvantages of 1, 2 and 3 are carry the notes respectively the book with you (think you are on your trip to America and don't want to fill your hole luggage with tons of books or do you want to travel without your favorite Simpsons trousers).

Method 4 is a reminder of important passages. If such a file is very long you have problems in searching the needed sections - you have to play forward and back and this is boring. Don't forget the amount of space which you need to store it. The advantage is, that you can easily take notes and train your language when your tongue is on air.

The usage of a specialized device for eBook-reading is a great opportunity. You can have many books on on your device, set bookmarks and can take notes. I think writing notes without a keyboard may have a worse usability - maybe with the iPad 2 its more easier. If you are used to this technology and you are are good then use it. You can make it public or lock it with a certain password. But why hidden your knowledge so that no other one can see it? Let other benefit by your conclusions and wisdom.

Personally for me the best method is to write my impressions of a read book on a sheet of paper and transform with my PC later. A further step may be publishing your notes to your website - you have the possibility to access your thoughts via an Internet connection. I'm using a desktop-wiki zim and wrote a bunch of handy scripts, which transform the text directly in format of my web page.

Conclusion

If I had known early I would have started with this methods during my education at school. But better later then never. If I travel for a longer period and have a book with me, it has still some sheets of papers in it, that I have space to take notes. A pencil is for me standard equipment. I can put every place where I read a book my thought about it on paper. If the book is finished and I have a little bit time left, I will transform it into my Netbook and then have my thoughts with me.

Remember: In the beginning it's unusual to make several breaks during reading a book, which breaks your normal flow of reading. But during these breaks you can reorder your thoughts about certain things and get new insights. I suggest to publish it online and then see what will happen with it.

Thanks to Hanna Schütt and Sebastian Gerth for reading an earlier draft of this post.

Why learning a new programming language

2011-10-08T00:00:00+00:00

"Why should you start learning a new programming language" was the questions I asked me in the 2011? Nowadays we are all too busy to try out new things, to expand our horizon. In the following chapter I will explain you, how I learned programming languages.

In the beginning there was Turbo Pascal

The first language I learned was Turbo Pascal. Everything (not only the programs) looked like a great "geek nerving god tool". I quite don't understand what I was doing with Turbo Pascal as my computer science teacher told me to make some simple calculation the perimeter for triangular and other geometric object. It was great to declare your variables and then put them into a function and print line the outcome. Here are some code snippets:

Turbo Pascal was my first procedural language and later during my studies I learned in a lecture about compiler construction that this language was developed 1970 by Niklaus Wirth (whom I admire for building such easy and effective techniques like the recursive descendant, but thats another tale). If you want to have this retro feeling check out Ubuntu resources (or other things if you want to stay up).

The following images show the IDE. It has few options with fancy looking buttons and no options-overload.

Nice blue environment.

A successful compilation.

Syntax highlighting looks like in a old hacker movie.

Output in a console.

In secondary school we had written some programs in Delphi (original it had the name Object Pascal). The new things was that even the girls had little fun in writing programs in it (some nice "Hello Kitty" in with pink color, but they actually love it). We learned how to write functions and to create some appealing graphics. After that I lost my interests in programming because the age of warhammer or video games.

Then Java came ...

When I started my studies of computer science I knew I had still no programming experience and during my first year I had to learn Java. It was quite good and quite bad if you ask my. The good things about it was that I had to learn an exhausting new methodologies: OOP, Interfaces, Recursion, Inheritance, Encapsulation, Polymorphism and many other concept. I was lost, I wanted to learn how to write simple programs and no one could tell me, why I have to write this public static void main (String args[]) to start my program. My fellow students told my that I was an absolute newbie (they were actually right).

Chad Fowler wrote in his book The Passionate Programmer: "Always be the worst guy in every band you're in." I actually was it and in now time I made great progresses. But some aspects of Java hit my but: It was so long to express simple things, so much overhead with static, private etc. To what I mean have a look on the following code:

class Socke {

  public String farbe;
  public int gewicht;
  private boolean istTrocken;

  void trockne() {
    istTrocken = true;
  }

  void wasche() {
    istTrocken = false;
  }

  boolean istTrocken() {
    return istTrocken;
  }
}

public class NewClass {
  public static void main(String args[]) {
    Socke stinki = new Socke();
    stinki.farbe = "schwarz";
    stinki.gewicht = 565;
    stinki.trockne();
    System.out.println(stinki.istTrocken());
  }
}

Ok, you may say: "It's quite readably" but wait until you have written, about several kilo of LOCs and want to maintain or refactor it. I thought that I could understand my "well" written mail client but well afterwards you know it better.

For another term I looked on C++. It was good to see how pointer (or references) are working, how you must allocate your memory (Java has it's ) and generics (or templates) for your data structures. C++ is like Java, it's OOP and you can program procedural if you like to. Have a look on some code:

/*
* 2.1
* Author: Matthias Guenther
* function: repeated shortening of breaches with a ggT
* use the Euklid-Algo to compute the ggT
*/

#include <iostream>
using namespace std;

int compute_ggT(int a, int b){
  if (b == 0){
    return a;
  } else {
    return compute_ggT(b, a % b);
  }
}

void shortening_breach(){
  int a, b, shortening_factor;
  string q;
  do {
    cout << "Please input the parameters to solve the breach: a/b\n";
    cout << "[Input] Parameter a: ";
    cin >> a;
    cout << "[Input] Parameter b: ";
    cin >> b;
    // look at the ggT
    if (b == 0){
      cout << "This is not allowed";
    } else {
      shortening_factor = compute_ggT(a,b);
      a = a / shortening_factor;
      b = b / shortening_factor;
      cout << "The breach is:" << a << "/" << b << "\n Continue?"
            "\n [Input \"q\" to leave the programm or \"c\" to "
            "continue]";
      cin >> q ;
      cout << "\n ";
      }
    } while (q != "q");
}

int main(){
  shortening_breach();
  return 0;
}

Enlightenment with Ruby

Normally I'm not the guy how runs after every hype but I haven't found my beloved programming language. Why not risk a look. And then there was this 'Whosh' (think DC Comics). You could program in different styles, could design your own languages (called DSL) and this nifty framework Ruby on Rails (RoR) with Test-Driven Development (TDD), Behavior Driven Development (BDD), Continuous Integration (CI) and many more things. These things sound a like a mystery for me, but just get started and see how "easy" you can use it with RoR. It hits my head.

It was a very hard steady learning curve but it was more pleasantly then just go to the candy shop and get what you want for nothing. You have to invest much time. But look for yourself on ruby - it looks like a natural language. Look at a script I wrote to tag MP3:

require "mp3info"

# setting the basedirectory
base_directory = "check/"

# run through all directories and get the mp3
Dir["#{base_directory}**/*.mp3"].each do |mp3|
  # get the directory
  arr_directory = mp3.split("/")[0..mp3.split("/").length-2]

  # empty string which will be merged to a string and which is needed for file renaming as a path
  directory_of_album = ""
  arr_directory.each do |part|
    directory_of_album << part + "/"
  end

  directory_of_album = directory_of_album.gsub("//", "/")
  mp3_track = ""

  # open the mp3 to read the id3 infos
  Mp3Info.open(mp3) do |track|
    # delete genre
    track.tag2.TCON = "Game"

    # check, if the track title exists
    if track.tag.title != nil
      # mp3 with an underscore are translated in / so we must catch this
      track_string = track.tag.title.gsub("/", "")
      track.tag.title = track_string
    else
      puts "Please set the track-tag for #{mp3.split("/").last} ... NOT converted"
    end
    # save mp3 tag
    mp3_track = track
  end

  # rename files
  if mp3_track.tag.title != nil
    mp3_newname = "#{Dir.pwd}/#{directory_of_album}#{mp3_track.tag.tracknum} - #{mp3_track.tag.title}.mp3"
    output = mp3_newname.split("/")
    File.rename(mp3, mp3_newname)
    puts "#{output[-1]} ... converted [#{mp3_track.tag.album}]"
  end
end

Automating tasks

I resisted very long to learn the bash, but there were so many tasks over the years which I didn't do because it gives me the heebie-jeebies to do the same thing over and over again. After one weekend studying the open book "The Linux Command Line" by William E. Shotts I caught fire. For a long time I messed my desktop up with tons of images with ugly names, so I wrote a script to change this. I have a bunch of images with ugly name, so I wrote a script to change this. Each command has it's purpose you have to learn its syntax. Here is some sample code:

#!/bin/bash
z=`ls | wc -l`
z=0

for i in *.jpg; do z=$[$z+1]; mv "$i" ${i##*.jpg}$z\_$1.jpg; echo $i ; done # replace watermark_ (prefix)

It's like Lego, you have these and that, plug it together to create something new. For my diploma thesis I create a Rakefile (the modern version of make written completely in ruby):

desc "Create a directory for the compiled classes"
task :create_class_directory do
  system 'mkdir -p classes'
end

desc "compile the plugin and put the files in the directory"
task :compile_plugin do
  system 'fsc -d classes Plugin.scala'
end

desc "copy the plugin descriptor"
task :copy_plugin_descriptor do
  system 'cp scalac-plugin.xml classes'
end

desc "create the jar file"
task :create_jar_file do
  system 'cd classes; jar cf ../divbyzero.jar .'
end

desc "create environment"
task :create_environment => [:create_class_directory, :compile_plugin, :copy_plugin_descriptor, :create_jar_file] do
  puts 'done with creating the jar file ...'
end

desc "compile the traits"
task :compile_traits do
  system 'fsc -d classes TraitProgrammingHelper.scala'
  system 'fsc -d classes TraitUpdaterHelper.scala'
  system 'fsc -d classes TraitArithmeticRulesHelper.scala'
  system 'fsc -d classes TraitBasicRulesHelper.scala'
end

desc "create environment with traits"
task :create_environment_complete => [:compile_traits, :create_environment]

desc "run example file"
task :test => [:create_environment_complete] do
  system 'scalac -Xplugin:divbyzero.jar Example.scala'
end

Head Scratching With Scala

I learned this language for my diploma-thesis, otherwise I still wouldn't put a thumb on FP. So far I must say that it was a good decision to learn an functional language. Scala showed me how to use chained function, anonymous functions, currying, type bounds and many more constructs. In the beginning my head howls like a steam-tank, there was so much new terrain for me that I need several breaks to get used to it. After many hours of happy cramming I got surprisingly insights in doing OOP better. That was is, what the Pragmatic Programmers were preaching. To get new insight in a technology you have to regard it's counterpart. Don't hesitate to do something you would never do, you gain experience and more confidence in your profession.

Here is some of Scala code:

class Reference[T] {
  private var contents: T = _
  def set(value: T) { contents = value }
  def get: T = contents
}

object IntegerReference {
  def main(args: Array[String]) {
    val cell = new Reference[Int]
    cell.set(13)
    println("Reference contains the half of " + (cell.get * 2))
  }
}

Conclusion

This was my first essay. I tried to cover the things which whom I'm actually dealing. I presented my wide route from my programming experience so that you can see, how the things evolved for me. I always get my hands dirty and try to roll up my sleeves to get a touch about the newest technology. I think through adventuring you become each day a little bit better then yesterday.

Method alias in ruby

2011-10-01T00:00:00+00:00

You can create aliases for a method and variable name in ruby. This can be helpful if you want to override the behavior of some method without changing the origin implementation of it. alias_method take a new_name as a copy name of the old_name and it has the following syntax.

alias_method (new_name, old_name)

A small example:

class Davi
  def capital
    puts "Karaz-a-Karak"
  end

  alias_method :orig_capital, :capital

  def capital
    puts "Karaz-a-Karak rebuild"
    orig_capital
  end
end

davi = Davi.new
davi.capital

# output
"Karaz-a-Karak rebuild"
"Karaz-a-Karak"

What is the difference between `alias` and `alias_method`

Alias will looks at the value of self lexically where the aliased keyword lies. Alias_method use the value of self during runtime which may be a subclass where the call is lexically located. Consider the following example to understand what I mean:

class A
  def self.swap
    alias bar foo
  end
  def foo; "A foo"; end
end
class B < A
  def foo; "B foo"; end
  swap
end
puts B.new.bar
# => "A foo"

class Y
  def self.swap
    alias_method :bar, :foo
  end
  def foo; "Y foo"; end
end
class Z < Y
  def foo; "Z foo"; end
  swap
end
puts Z.new.bar
# => "Z foo"

Conclusion

It is possible with alias_method to reopen a class, override a method call and you can still use the original call. In order to maintain backward compatibility alias_method are used in plugins, extensions, deprecating variables. Alias_method can be used in Rails to define action with duplicated content and remove duplicated code.

Here the duplicated variant:

class UsersController < ApplicationController
  def home
    list
  end

  def find
    list
  end

  def search
    list
  end
end

The DRY variant:

class UsersController < ApplicationController
  def home
    list
  end

  alias_method :find, :home
  alias_method :search, :home
end

Why I use Jekyll for blogging

2011-07-03T00:00:00+00:00

For several years I want to write and tried many different platforms like WordPress blogger, or tumblr. The main problem which kept me away from writing was just the fact, that every time I want to write I had to do it in a new environment and not in my favorite editor vim. Every system gives me the freedom to extend it in several ways but in the end it didn't provide me the freedom to change every tiny piece I want. With jekyll I can use my favorite text editor and it really "turned me into a text monster". This description sounds like a holy grail, but let me explain its abilities in the following sections.

What Jekyll is

Jekyll is a static site generator written in ruby. It generates static html pages. The page is presented through several templates and then fires the whole site, were articles are written in a text markup language like Textile or Markdown through the liquid converters to generate fully generated compiled website. Don't think that it will be easy for you to do it. First of all you have to learn either Textile or Markdown. I chose textile for writing my posts because I use Markdown to create the README files for my GitHub account.

Setting up the environment

You need to have a valid ruby and ruby gems installation on your machine. A simple gem install jekyll will install the following gems:

directory_watcher: gives a list of files which change in some intervals
liquid: rendering templates in a safe manner
open4: creates a child process to handle pid, stdout, etc.
maruku: (Markdown interpreter
classifier: is a Bayes implementation and can be used semantic indexing like to display related post - this mechanism is used in machine learning)

To get nice syntax highlighting for your code you have to install pygments via sudo apt-get install python-pygments on Ubuntu/Debian. On the "install page(install link for jekyll install you can get more information about how to setup Jekyll.

The directories and styles

Here is the basic layout of a typical Jekyll project:

_includes: Small snippets which can be used in every place of the page.
_layouts: You can define layouts for post entries and the general default layout. Posts can have the special Yaml Front Matter.
_posts: Contains all posts in your specified markup language
_config.yml: Is a file to store configuration data like the styling of the URLs, or some global variables. It is also possible to define own variables which can be used as global things on other pages.

Other files can put on the root directory like an atom.xml file (for RSS feed) or 404.html page. For example my post.html has the following layout:

---
layout: default
---
<article>
  <header>
    <div class="author">
      Posted on <time datetime="2011-07-03" pubdate>2011-07-03</time>
    </div>
    <div class="social">
  <a href="//www.reddit.com/submit?url=/why-i-use-jekyll-for-blogging/" target="_blank">
    <i class="fa fa-lg fa-reddit-square"></i>
  </a>

  <a href="//news.ycombinator.com/submitlink?u=/why-i-use-jekyll-for-blogging/&amp;t=Why I use Jekyll for blogging" target="_blank">
    <i class="fa fa-lg fa-hacker-news"></i>
  </a>

  <a href="http://twitter.com/share?url=/why-i-use-jekyll-for-blogging&amp;text=%22Why I use Jekyll for blogging%22%20%40wikimatze" target="_blank">
    <i class="fa fa-lg fa-twitter-square"></i>
  </a>

  <a href="http://www.facebook.com/share.php?u=/why-i-use-jekyll-for-blogging" target="_blank">
    <i class="fa fa-lg fa-facebook-square"></i>
  </a>

  <a href="https://plus.google.com/share?url=/why-i-use-jekyll-for-blogging" target="_blank">
    <i class="fa fa-lg fa-google-plus-square"></i>
  </a>

  <a href="http://feeds.feedburner.com/guenther?format=xml">
    <i class="fa fa-lg fa-rss-square"></i>
  </a>
</div>


    <div class="clearfix"></div>
  </header>
  <div class="clearfix"></div>

  <br>
  <aside>
    <div class="whoring">
  <div id="disqus_thread"></div>
  <script type="text/javascript">
    /* * * CONFIGURATION VARIABLES: EDIT BEFORE PASTING INTO YOUR WEBPAGE * * */
    var disqus_shortname = 'wikimatze'; // required: replace example with your forum shortname

    /* * * DON'T EDIT BELOW THIS LINE * * */
    (function() {
        var dsq = document.createElement('script'); dsq.type = 'text/javascript'; dsq.async = true;
        dsq.src = 'http://' + disqus_shortname + '.disqus.com/embed.js';
        (document.getElementsByTagName('head')[0] || document.getElementsByTagName('body')[0]).appendChild(dsq);
    })();
  </script>
  <noscript>Please enable JavaScript to view the <a href="http://disqus.com/?ref_noscript">comments powered by Disqus.</a></noscript>
  <a href="http://disqus.com" class="dsq-brlink">comments powered by <span class="logo-disqus">Disqus</span></a>
</div>


  </aside>
</article>

The lines between --- mark a special Yaml Front Matter This block is treated as a special block in Jekyll and can contain different components. The `` stands for the content of a post entry.

Creating the layout

Here is the main template for my blog.

<!doctype html>
<!-- paulirish.com/2008/conditional-stylesheets-vs-css-hacks-answer-neither/ -->
<!--[if lt IE 7]> <html class="no-js ie6 oldie" lang="en"> <![endif]-->
<!--[if IE 7]>    <html class="no-js ie7 oldie" lang="en"> <![endif]-->
<!--[if IE 8]>    <html class="no-js ie8 oldie" lang="en"> <![endif]-->
<!--[if IE 9]>    <html class="no-js ie9" lang="en"> <![endif]-->
<!-- Consider adding an manifest.appcache: h5bp.com/d/Offline -->
<!--[if gt IE 9]><!--> <html class="no-js" lang="en" itemscope itemtype="http://schema.org/Product"> <!--<![endif]-->
<head>
  <meta charset="utf-8">

  <title>Why I use Jekyll for blogging</title>


  <meta name="description" content="Writings, and talks by Matthias Günther. Günther works at MyHammer, loves painting Warhammer figures, and enjoys making cakes.">

  ...
</head>

<body>
  <div class="navbar row" id="nav2">
    <a class="toggle" gumby-trigger="#nav2 > ul" href="#"><i class="icon-menu"></i></a>
    <h1 class="four columns logo">
      <span id="title">
        <a href="/index.html">wikimatze</a>
      </span>
    </h1>
    <ul class="eight columns">
      ...
    </ul>
  </div>

  <div class="row">
    <div class="push_one ten columns">

    <header><h1 class="lead">Why I use Jekyll for blogging</h1></header>


    </div>
  </div>

  <div class="modal" id="modal1">
    <div class="content">
      <a class="close switch" gumby-trigger="|#modal1"><i class="icon-cancel" /></i></a>
      <div class="row">
        <div class="ten columns centered">
          <h2>Contact</h2>
          ...
        </div>
      </div>
    </div>
  </div>

  <footer class="row">
    <nav>
      ...
    </nav>
  </footer>

  <!-- Grab Google CDN's jQuery, fall back to local if offline -->
  <!-- 2.0 for modern browsers, 1.10 for .oldie -->
  <script>
  var oldieCheck = Boolean(document.getElementsByTagName('html')[0].className.match(/\soldie\s/g));
  if(!oldieCheck) {
    document.write('<script src="//ajax.googleapis.com/ajax/libs/jquery/2.0.2/jquery.min.js"><\/script>');
  } else {
    document.write('<script src="//ajax.googleapis.com/ajax/libs/jquery/1.10.1/jquery.min.js"><\/script>');
  }
  </script>
  <script>
  if(!window.jQuery) {
    if(!oldieCheck) {
      document.write('<script src="js/libs/jquery-2.0.2.min.js"><\/script>');
    } else {
      document.write('<script src="js/libs/jquery-1.10.1.min.js"><\/script>');
    }
  }
  </script>

  <!--
  Include gumby.js followed by UI modules followed by gumby.init.js
  Or concatenate and minify into a single file -->
  <script gumby-touch="/js/libs" src="js/libs/gumby.js"></script>
  ...
</html>

I'm using the meta-language Sass to create my CSS. There is one problem with Sass: You have to compile it every time you made a change. Fortunately, there is the compass which always compiles my sass file when I change it. When I build my page I started with compass watch css/ & a command to automate Sass building. This is very handy when changing the layout.

Conclusion

Look on other pages what is possible with Jekyll. You can learn many new things by looking at other Jekyll blogs and copy what you need. I love to write a little bit and after I finished an article perform rake d to upload my blog.

Matthias Günther

Talk about Weechat another IRC client

Ranger a terminal browser for Vim

Installation

Navigation shortcuts

Working with Files:

General shortcuts

Command interface

Customizing ranger

rc.conf

Vim command to start the browser mode

VCS awareness

Links

Vimtex the perfect tool for working with tex and Vim and Zathura

Benefits of using this plugin

latexmk installation and configuration

Ensure that libsynctex is on your system

girara and zathura installation

vimtex basics

vimtex forward and backward search for zathura

Useful vimtex commands

Migration RSS from FeedBurner to Feedio

RSS in the wild

Get your feedburner users

Ways to link your RSS feed

Create a apache redirect for your atom

Feedio

Better zsh with Prezto

Installation

Configure your .zpreztorc

Prompt color themes

Custom prompt color theme

Get rid of options-groups

Problems with tmux

Command-line completion speedup with prezto

Links

Scrum Master Certification

Using Grub Customizer to manage the Bootloader

Installation

Usage

Encrypt Your External Device

Further reading

Talk about Git and Vim - maximize the joy and fun

Show the most common used terminal commands

Google Chrome Start Problem

Installing Printer Driver For Brother HL-2240D Under Xubuntu

Get the sources

Installation

Code Coverage Tools For Padrino

Learn more about Padrino Book? Sign Up!

Available Tools

Simplecov

metric_fu

Code Climate

Learn more about Padrino Book? Sign Up!

Highlight Bad Words In Vim

Learn more about Padrino Book? Sign Up!

Learn more about Padrino Book? Sign Up!

Clutter Highlighting Function in Vim

Learn more about Padrino Book? Sign Up!

RespImgPageCache not found in cache.inc file for Drupal

Global Gitignore

Github Two-Factor Authentication Failed For HTTPS

Two-Factor Authentication

Enabling Two-Factor Authentication

Setting Up a Personal Access Token

Testing your Personal Access Token

Pushing to a HTTPS Github URL on Your Own

Pushing to a HTTPS GitHub URL on an Organization

Use .netrc File To Store Credentials

Encrypt .netrc file with GPG

Update About the organization push problem

Deploying Padrino Applications On Heroku

Learn more about Padrino Book? Sign Up!

Installing Heroku

Hello World

Database Deployments With Heroku

Learn more about Padrino Book? Sign Up!

Making Firefox as Fast as Chrome

Slow Firefox