# 2. Getting Started - Commands
This tutorial is based on example code in the Welcome Projects.
A command is a single executable string executed on a Node. Rundeck invokes commands on nodes via a node executor which evaluates the command string and executes it. Node executors evaluate the command string in a data context containing information about the Node resource. Command strings can reference this data and thus avoid hard coding node or environment specific values.
The Rundeck graphical console provides the ability to execute commands to a set of filtered Node resources. The Command page can accept any command string you might run via on the node's console. In the previous step we confirmed our new nodes were in our Nodes List. Use the exercise below to run a command against the new nodes.
This will execute the command against your Linux based Rundeck Server and return the Operating System information. There should be a line for each node you have configured.