Defining and using Kettle variables

In Chapter 3, Creating Basic Task Flows, you were introduced to Kettle variables. This section resumes the subject by explaining to you all the kinds of Kettle variables, how to define them, and all the ways to use them.

Introducing all kinds of Kettle variables

Kettle variables can be defined in several ways, and with the different scope. You already know about predefined variables and variables defined in the kettle.properties file, but there are more options. The following subsections summarize them all.

Explaining predefined variables

Predefined variables are Kettle variables mainly related to the environment in which PDI is running. These variables are ready to be used both in Jobs and Transformations and their scope is the Java Virtual Machine (JVM).

The following table lists some of the most used predefined variables:

Subject	Predefined variables
Operating system	${os.name}, ${os.version}
Current user	${user.home}, ${user.name}, ${user.timezone}, ${user.language...