In PowerShell, variables are used to store data values that can be referenced and manipulated throughout a script or a session. Here's how variables work in PowerShell:

Defining a Variable: To create a variable, you need to use the "$" sign followed by the variable name, an equal sign "=", and then the value you want to assign to the variable. For example, to create a variable called "name" and assign it the value "John", you would use the following command:

$name = "John"

Using a Variable: Once you have created a variable, you can reference it by typing its name preceded by the "$" sign. For example, to display the value of the "name" variable, you would use the following command:

Write-Host $name

This would output the value "John" to the console.

Modifying a Variable: You can also modify the value of a variable at any time by simply assigning a new value to it. For example, to change the value of the "name" variable to "Jane", you would use the following command:

$name = "Jane"

Variable Scope: Variables in PowerShell can have different scopes, which determine where they can be accessed from. There are several types of variable scopes, including:

Global: A global variable can be accessed from anywhere in the script or session.

Script: A script variable can only be accessed within the current script.

Local: A local variable can only be accessed within the current function or script block.

You can define the scope of a variable by using the appropriate keyword when defining the variable. For example, to define a global variable, you would use the following command:

$global:name = "John"

This would create a variable called "name" with global scope, which could be accessed from anywhere in the script or session.

Overall, variables in PowerShell are an essential tool for storing and manipulating data values, and understanding how to use them effectively is a key part of writing PowerShell scripts.