More that 100 remote, solar-powered, stations record water flow and capacity data from canals, rivers and reservoirs. This data is collected and disseminated by the the MetriDyne tool, created by Moki Systems.

A schematic view of a portion of the system is useful as an overview for operations:

A tabular view of the same data:

Drilling down on an individual station shows a time series graph with options for tabular display or data export:

This is a full-time position with a 90-day probationary period after which medical benefits and paid holidays are available. Salary is competitive and depends on experience.

Send a resumé to:

Kelli Valadez

Contact Phone:
435-674-3571

Contact Email:
hr@mokisystems.com

$ cd ~/.snippets
$ ls -1
credit_card
email
@example.com
phone
RAILS_ENV=test
sql_create
sql_permissions
$ cat credit_card 
4111111111111111
$ cat sql_permissions 
GRANT ALL PRIVILEGES ON .* TO ''@'localhost' IDENTIFIED BY ''
$ cat phone 
#!/usr/bin/env ruby
print (1..12).map {i i == 4  i == 8 ? '-' : rand(10).to_s}.join

Then I put this little script in ~/bin:

#!/bin/bash
# http://bbs.archlinux.org/viewtopic.php?id=71938
DIR=${HOME}/.snippets
DMENU_ARGS="-i -fn -*-terminal-*-*-*-*-18-*-*-*-*-*-*-*" # xfontsel to select font
 
FILE=`/bin/ls $DIR | /usr/bin/dmenu ${DMENU_ARGS}`
 
if [ -x ${DIR}/${FILE} ]; then #executable
echo -n `${DIR}/${FILE}` | xsel -b -i
elif [ -f ${DIR}/${FILE} ]; then
cat ${DIR}/${FILE} | xsel -b -i
fi
xdotool key ctrl+v # for non-console
xdotool key ctrl+shift+v # for console

And then I mapped that script to a handy key combination in compiz. So now whenever I need a test credit card number, phone number, or email address I can just do c, type the first few characters to select the right snippet, hit return and it gets pasted in to whatever I’m working on.

Notes and caveats:

• I had to aptitude install some packages to get dmenu and xdotool to work.
• dmenu is ugly and has no mouse support.
• Pasting into vim has occasional issues.

cc = CreditCard.new(:card_number => 'invalid')
>> cc.save
=> false
>> cc.id
=> 3

That one had me stumped for a while until I realized I was carelessly using update_attribute in my custom writer:

def card_number=(num)
  update_attribute(:crypted_card_number, encrypt(num))
end

And we all know that update_attribute “saves the record without going through the normal validation procedure.”

Everything worked much nicer after I changed the code to:

def card_number=(num)
  self.crypted_card_number = encrypt(num)
end

These are standard shell tools, but sometimes I get confused about which one I need. So my way of thinking about it is that pipes are a connection between programs while redirection always goes to (or from) a file.

So, for example, in order to find all my session routes I would connect the rake and grep commands via a pipe:

  rake routes | grep session

On the other hand, I would use redirection to save the output of a git diff to a file so as to be able to feed it in to the patch program (which expects its input on standard in).

  git diff > patchfile
  patch < patchfile

Braces

I just learned about these recently and they make renaming things so much easier!

  mv file.old file.new # old way
  mv file.{old,new} # does the same thing!

So creating your database.yml file from the example one is as easy as:

  mv config/database.yml{.example,}

Changing Directories

I assume everyone already knows that cd with arguments goes to your home directory (the contents of the $HOME environment variable), but did you know you can do 'cd -' to go to the previous directory you were in ($OLDPWD)?

  :/var/www$ cd /etc/apache2/sites-enabled/
  :/etc/apache2/sites-enabled$ cd -
  /var/www
  :/var/www$

History

!! # execute the previous command (great for when you forget to sudo something)
!$ # The last argument of the previous command
!^ # The first argument
!* # All the previous arguments
^old^new^ # Repeat the previous command replacing old for new

And lots, lots more! See 'man history' for details.

Keyboard shortcuts

Here are a few of the keyboard shortcuts that I use regularly (copied from the wikipedia article http://en.wikipedia.org/wiki/Bash):

CTRL + l : clears the screen content (equivalent to the command : clear).
CTRL + u : clears the line content before the cursor and copy it in the clipboard.
CTRL + k : clears thctrl alt copy pastee line content after the cursor and copy it in the clipboard.
CTRL + w : clears the word before the cursor and copy it in the clipboard.
CTRL + y : (yank) adds the clipboard content from the cursor position.

>> (19.99 * 100).to_i
=> 1998
>> (9.99 * 100).to_i
=> 999

Someone please tell me what’s up with that!

In the meantime:

>> (19.99 * 100).to_s.to_i
=> 1999

Gotcha #1


>> Rails.version
=> "2.1.1"
>> Client.find_all_by_notify_by(%w(email txt both)).size
=> 2



>> Rails.version
=> "2.2.2"
>> Client.find_all_by_notify_by(%w(email txt both)).size
ActiveRecord::StatementInvalid: Mysql::Error: Operand should contain 1 column(s): SELECT * FROM `clients` WHERE (notify_by = 'email','txt','both' AND clients.deleted_at IS NULL)
>> Client.find(:all, :conditions => ["notify_by = ? OR notify_by = ? OR notify_by = ?", *%w(email txt both)]).size
=> 2


Gotcha #2


>> Rails.version
=> "2.1.1"
>> Client.find_all_by_agent_id(nil).size
=> 26



>> Rails.version
=> "2.2.2"
>> Client.find_all_by_agent_id(nil).size
=> 0
>> Client.find(:all, :conditions => "agent_id IS NULL").size
=> 26


They asked me to trouble shoot the problem; with no clue as to what the problem should be.

To begin with I decided to find out the size of each individual table to determine if it was any particular table that was the problem.

To calculate the table sizes I wrote a query to put all of the table sizes into a table that could easily be read and shared with the client as follows:

create table temp_tablesizes (

Looking at the table sizes in the temp_tablesizes database we discovered that 90% of the size was allocated to a table which was suppose to have a maximum of two records per account each record being a large sound file. We discovered that the tool which deleted old recordings wasn’t working and where able to resolve the problem of an excessively large Microsoft SQL Server database.