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[[Variables]]
:openvar: ${
:closevar: }
:imagesdir: ../../assets/images

Parameterize everything! xref:variables.adoc[Variables] provide an easy way to avoid hard-coding all sorts of things in your system, environment or project.

* Put environment specific settings in one or more xref:projects/projects-environments.adoc[environment] configuration files. This allows you to deploy your project to another environment (dev/uat/prod) without changing your project, you'll only need to configure another set of configuration files.
* When referencing file locations, prefer `{openvar}PROJECT_HOME{closevar}` over expressions like `{openvar}Internal.Entry.Current.Directory{closevar}` or `{openvar}Internal.Pipeline.Filename.Directory{closevar}`
* Configure transform copies with variables to allow for easy transition between differently sized environments.
* use the xref:variables.adoc#_environment_variables[Environment Variables] to keep your projects and environments, audit information etc outside of your Apache Hop installation.
