Posts

Service Engineer/System Administrator Interview Questions

This is not my code alone.  It was the group effort of Vivek Ram, Cijo George, Sandeep Unni and mine during our epic preparation for Yahoo!. I am just putting it open for others who would be looking for this information. Convert all lower case to upper  …

Generate Date from a range in Mysql and pad the results where no date is present

If you want to generate dates, MYSQL doesn’t have a range function, so I wrote a work around for the same. So how  it works is I have reused a code to generate numbers from my previous post. So I added date function to that query and reduce the generated  …

Batch Insert/Update for Mysql in Java

Large inserts/Updates are a costly operation. One foolish way that I used to do is to run each update or insert query one at a time. Its incredibly slow. With most of the systems currently the latency is what is killing the performance not the CPU. Hence l …

Generate 1 to 1000 in mysql

Sometimes its necessary to have thousand rows to join or generate new values, we need to get the thousand rows first. For this I used union of numbers 0-9.  I have joined four of these to get to four digit values. So here is the code:



SELECT @row := …

Ontology Linked Data

The following is a Assignment on Ontology and Linked Data and the evolution of data which lead to the use of ontology in web. Thanks to my teammates Bharath Gowda and Sravani Thota for working on the same. Ontology And Linked Data An ontology formally r …

Automatic Command Archive

The default command storing size of ubuntu is 500 commands. It stores the commands in home folder in the file “.bash_history” . The problem is 500 commands is too short of a size. One method is to increase the command size to a large value by changing the  …

Group by Date when Stored in Mysql DataBase as Date Time

I have a table called date_count with 2 columns one is a value and another is a date time, say called date_time in mysql. Date Time in mysql is stored as dd-mm-yy hh:mm:ss. The issue comes when I need to get the number of rows per day. As its stored as dat …

How to Format a Usb in Linux

There are two methods of formatting a usb in linux that I use. The first method is using gparted (or parted non gui version of gparted). This is an easy gui interface that uses shell commands as backend. It is easy to do it. You install this package usin …

Sort according to the nth Column in Shell Script

You have a file that has multiple columns separated by a specific delimiter and you need to sort it according to a specific column which need not be the 1st column. If its not the 1st column then ordinary sort wont work. So we need to use the parameters of …

Installing Django on Dreamhost

Installing Django in Dreamhost and getting it to run wasn’t straight forward at-least to me. There was lot of issues such as python bin directory not accessible as its shared and so. So the initial step in this to setup python yourself so that you can use …