This post is a review of fundamental Java and programming concepts. Java Class Structure A Java class is described in a text file with a .java extension. In the example shown below, the Java keywords are highlighted in bold. package [package_name]; import [other_packages]; public class ClassName { [variables(also known as fields)]; [constructor(s)]; [other methods]; } […]
How to monitor your CPU on debian or ubuntu systems
There are many reasons to want to monitor your CPU maybe if you are over-clocking(making sure your CPU hasn’t caught fire after running Prime95), or you might just be interested to look at your CPU temps, there are lots of different reasons and this is a post to show you how. For both of these […]
How to fix the “Firefox already running” problem on Linux
After creating a script that included closing a firefox tab and hiding the window I realized I could not open firefox and just got a “Firefox is already running” error every time after running this script once. I tried running the command: $ sudo killall firefox As there may have been some hidden windows however […]
How to create a Python Dictionary
Dictionaries in python are quite similar to arrays in how they look however arrays are indexed by a range of numbers i.e. 1-10, but dictionaries are indexed by their key. You can set these keys to immutable data types only. They can also be known as key pair arrays. You will be used to seeing […]
Command line parameters in shell scripts
Command line parameters are a way to pass information into a program or script in order for it to do what you want it to. Some examples of command line parameters: $ ls -l $ cat textfile The command line parameters here are the “-l” and “textfile”. How are command line parameters accessed within a […]
How to format code within web pages
When displaying code within web pages it can be hard to read if it hasn’t been separated from the other text and images on the page. To get around this problem you can use google code-prettify JavaScript. This allows code to be displayed like this: To implement this within your HTML you need to add […]
Python Quadratic Formula
An equation with the form ax^2+bx+c=0 is known as a quadratic equation. When plotted on a graph it will take the general shape of the graph seen below. The points at which the quadratic graph crosses the x-axis are known as the solutions of the quadratic equation. For this example, the quadratic crosses the x-axis […]
How to Check if the script is run by root at the start of the script
Check root at start of script Some scripts need to be run as root and you may want to check at the start of that script that it is running as root. This can be done by checking the environment variable $EUID. This variable will hold the value 0 if it’s being run as root. […]
How to check which options or features are used in the Oracle database
This post explains how you can check which options or features are used in the database. This is particularly useful for licensing purposes or when you want to de-install a certain option. This can be achieved through the DBA_FEATURE_USAGE_STATISTICS view. This view will list the feature usage on a per patchset basis. So the combination […]
ASM disk addition/deletion hung with no rebalancing
The Problem 1. Several disks have been added to an existing diskgroup in RAC environment and sqlplus session initiating adding operation does not return the control which have to be disconnected manually. 2. Rebalance is not occuring from v$asm_operation: SQL> select * from gv$asm_operation; no rows selected 3. “disk validation pending” message in other nodes […]