Variables in PowerShell are preceded by the dollar symbol ($), for example:

$MyVariable 

The name of a variable may contain numbers, letters, and underscores. For example, each of the following is a valid name:

$123 
$x 
$my_variable 
$variable 
$varIABle 
$Path_To_File 

Variables are frequently written in either camel case or upper-camel case (also known as pascal case). PowerShell does not enforce any naming convention, nor does it exhibit a convention in any of the automatic variables. For example:

• $myVariable is camel case
• $MyVariable is upper-camel case or pascal case

I suggest making your variable names meaningful so that when you come and visit your script again after a long break, you can identify its purpose. I recommend choosing and maintaining a consistent style in your own code.

It is possible to use more complex variable names using the following notation:

${My Variable} 
${My-Variable} 

The following notation, where a file path is written as the variable name, allows variables to be stored on the filesystem:

${C:WindowsTempvariable.txt} = "New value" 

Inspecting the given file path shows that the variable value has been written there:

PS> Get-Content C:WindowsTempvariable.txt
New value

Variables do not need to be declared prior to use, nor does a variable need to be assigned a specific type, for example:

$itemCount = 7 
$dateFormat = "ddMMyyyy" 
$numbers = @(1, 9, 5, 2) 
$psProcess = Get-Process -Name PowerShell 

It is possible to assign several variables the same value in one statement. For example, this creates two variables, i and j, both with a value of 0:

$i = $j = 0