PowerShell Basics: Variables and Data Types

Written by Ibhadogiemu Esemuede Okougbo on the 27th Aug 2021

Exported on 11-Nov-2021 12:04:53

POWERSHELL VARIABLES ON ATTUNE

This is a Blueprint on Attune on how variables and data type work in PowerShell

Variables in PowerShell can store all types of values. For example, it can store the results of commands, expressions like names, paths and values.

Variable names are not case-sensitive, they can include spaces and special characters.

There are different types of variables in PowerShell:

User-created variables: These are variables that are created and maintained by the user.

Automatic variables: These are variables that are created by PowerShell. Their values change as required to maintain their accuracy.

Users can't change the value of these variables. For example, the $PSHOME and $HOST variables.

Preference variables: These variables store user preferences for PowerShell. They are created by PowerShell and are populated with default values (we won't dive into this).

Variables created in the PowerShell command line exist only in the current PowerShell session, when the session is closed all variables are deleted.

Parameters

Name Type Script Reference Default Value Comment
Attune Node Windows Server attuneNode This is an Attune Node
Attune Node Credentials Windows OS Credential attuneNodeCredentials This is my Attune Node Credential

1 - Variables & Data Types

Below shows the basic way of declaring a Variable:

First by using the $ in front of an alphabet:

Example: - $a - $b

Variables are not case-sensitive in PowerShell, meaning $a is the same as $A

If used in an example:

$A = "AttuneOps"

$a = "Attune"

$a will overwrite \$A because it was declared after $A

Another way of declaring Variables is Using the CMDLET [New-Variable], a base syntax is below:


New-Variable -Name <variable name> -Value <value>

The parameter -Name takes in any alphabet or word "string" as the name variable.

The parameter -Value takes in any DataType (String, Array, Int, HashTable).

Data Types: This is a classification that dictates what a variable can hold.

PowerShell has several Data Types, a few of them are used in this Blueprint.

Examples of common data types are: - String - Arrays - Int32 - Objects or what we call HashTables.

To check the data type of a variable in PowerShell we make use of the GetTypes() method.

The Example in this Blueprint makes use of the two ways of creating a variable.

Also made use of the GetType() method to get the data type of the variables.

Then we echoed out the Name of the variables declared, the Value and the Data Type.

We made use of the Get-Variable CMDLET and Remove-Variable CMDLET to get all the variables in the session and then delete them. ("code complexity" issues).

The connection details have changed from the last step.

Login as user on node

  1. Connect via RDP 
    mstsc /admin /v:Attune Node
  2. Login as user {Attune Node Credentials}
  3. Then open a command prompt
This is a PowerShell Script make sure you run it with powershell.exe Click start menu, enter "powershell" in the search bar, then select the powersehll program 
#Region Variables and Data Types
#==============================================================================

# This gets all the variables in the Powershell Session and deletes them (to avoid the error of already existing variables)
Get-Variable | Remove-Variable -ErrorAction SilentlyContinue

#Region INT
#==============================================================================
# This Variable "FirstNumber" is of datatype System.Int32 ("data type = Int32")
$FirstNumber = 1

# `n - it creates a new line after the message.
# This is a print to screen CMDLET [Write-Host].
Write-Host "FirstNumber has a value of" $FirstNumber "and Data Type of" (($FirstNumber).GetType()).Name `n

# Pause the script for 1 Seconds
Start-Sleep -s 1

# This Variable "SecondNumber" is of datatype System.Int32 ("data type = Int32")
New-Variable -Name "SecondNumber" -Value 2               

# `n - it creates a new line after the message.
# This is a print to screen CMDLET [Write-Host].
Write-Host "SecondNumber has a value of" $SecondNumber "and Data Type of" (($SecondNumber).GetType()).Name `n
#EndRegion INT
#==============================================================================


#Region STRING
#==============================================================================
# This Variable "FirstString" is of datatype System.String ("data type = String")
$FirstString = "ATTUNE"

# Pause the script for 1 Seconds
Start-Sleep -s 1

# `n - it creates a new line after the message.
# This is a print to screen CMDLET [Write-Host].
Write-Host "FirstString has a value of" $FirstString "and Data Type of" (($FirstString).GetType()).Name `n

# This Variable "SecondString" is of datatype System.String ("data type = String")
New-Variable -Name "SecondString" -Value "AttuneOps"

# Pause the script for 1 Seconds
Start-Sleep -s 1

# `n - it creates a new line after the message.
# This is a print to screen CMDLET [Write-Host].
Write-Host "SecondString has a value of" $SecondString "and Data Type of" (($SecondString).GetType()).Name `n
#EndRegion STRING
#==============================================================================


#Region ARRAY
#==============================================================================
# This Variable "FirstArray" is of datatype System.Array ("data type = Array")
$FirstArray = @(3, "POWERSHELL")

# Pause the script for 1 Seconds
Start-Sleep -s 1

# `n - it creates a new line after the message.
# This is a print to screen CMDLET [Write-Host].
Write-Host "FirstArray has a values of" $FirstArray[0]"," $FirstArray[1] "and Data Type of" ((($FirstArray).GetType() | Select-Object BaseType).BaseType).Name `n

# This Variable "SecondArray" is of datatype System.Array ("data type = Array")
New-Variable -Name "SecondArray" -Value @(4, "BASH")

# Pause the script for 1 Seconds
Start-Sleep -s 1

# `n - it creates a new line after the message.
# This is a print to screen CMDLET [Write-Host].
Write-Host "SecondArray has a values of" $SecondArray[0]"," $SecondArray[1] "and Data Type of" ((($SecondArray).GetType() | Select-Object BaseType).BaseType).Name `n
#EndRegion ARRAY
#==============================================================================


#Region HASHTABLE
#==============================================================================
# This Variable "FirstHashTable" is of datatype System.Object ("data type = Object or HashTable")
$FirstHashTable = @{ ID = 4; Name = "WINDOWS" }

# Gets the Datatype and assigns it to the Variable $DataTypeHastableOne
$DataTypeHastableOne = (($FirstHashTable).GetType()).Name

# Pause the script for 1 Seconds
Start-Sleep -s 1

# `n - it creates a new line after the message.
# This is a print to screen CMDLET [Write-Host].
Write-Output "FirstHashTable has above below and Data Type of $DataTypeHastableOne" $FirstHashTable `n

# This Variable "SecondHashTable" is of datatype System.Object ("data type = Object or HashTable")
New-Variable -Name "SecondHashTable" -Value @{ ID = 05; Name = "LINUX" }

# Gets the Datatype and assigns it to the Variable $DataTypeHastableTwo
$DataTypeHastableTwo = (($SecondHashTable).GetType()).Name

# Pause the script for 1 Seconds
Start-Sleep -s 1

# `n - it creates a new line after the message.
# This is a print to screen CMDLET [Write-Host].
Write-Output "SecondHashTable has values below and Data Type of $DataTypeHastableTwo" $SecondHashTable `n
#EndRegion HASHTABLE
#==============================================================================
#==============================================================================
#EndRegion Variables and Data Types