(R)?ex is a server orchestration tool. Use the rexx tag if you want to refer to the REXX programming language.
(R)?ex is a server orchestration tool that doesn't need an agent on the hosts you want to manage. In fact it uses ssh to execute the given commands.
To use (R)?ex you don't need Perl knowledge at first. (R)?ex uses a simple DSL to describe your servers. Indeed, it is also possible to use (R)?ex from within your shell scripts without using perl at all.
In fact, if you know a little bit perl it won't hurt you.
The starting point of every (R)?ex project is the so called Rexfile. You can think of this file like a Makefile. You can define tasks in this file.
A task is a bunch of related commands. For example installing a package, uploading the configuration file and starting the service. You can also call tasks from other tasks or create rollback scenarios if something went wrong during the execution.