Technology Insights

Basic Linux Part 1: Command-line CD Fu

Alex and I are going to start a series on basic Linux shell commands and all the neat things you can do from the terminal. In my opinion there is a shortage of these type of articles on the internet. We are going to try to cover most every basic task and show how it can be done in the shell with no GUI or Desktop at all.  I am going to start out with this article on cd recording, but we will cover such topics as watching movies in the framebuffer, connecting to wireless via the shell, shell based irc chat clients, mysql commands and many more things. I have no idea how many articles there will be in the series but if anyone has a specific request or question you can always post in our engage question and answer section for a more personalized response.

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Technology Insights

Create Ruby Migration To Add An Index To A PostgreSQL Table

The other day I did some optimization work on a PostgreSQL database and at the end needed to create migrations so the changes I was going to make could be deployed on multiple servers. It was my first shot at migrations so I wanted to note for myself and anyone else that may find it useful how to create Ruby migrations for dropping and adding Indexes on PostgreSQL tables. Below you will find the basic concept for creating a migration that adds a Postgres table index and information on removing a table index which is just the reverse of adding.

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Technology Errors

ExtractionError: Can’t extract file(s) to egg cache, [Errno 13] Permission denied: ‘/root/.python-eggs’

I received an error when configuring a Django run site for the first time. The setup included installing and configuring some items I am not so familiar with such as mod_python, Django, and other Python items. I finally started making some progress and when I initially launched a test site I received the below errors in the debug output.

Short Error: ExtractionError: Can’t extract file(s) to egg cache

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Technology Errors

error: invalid Python installation: unable to open /usr/lib/python2.4/config/Makefile (No such file or directory)

I received the error below when attempting to use easy_install to add the html5lib package on a server for a client. I assumed all of the necessary python packages were installed since easy_install was already available via python-setuptools-devel. After a quick investigation I noticed that the python-devel package was not installed. This can easily be installed on CentOS Linux using yum with the directions below.

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