Learn Powershell Scripting Tutorial Full Course 1dollarcart.com.pdf

1
Learn Powershell
Scripting Tutorial Full
Course

1. Basics of Powershell
2. Unit Testing with Pester

Powershell Basics
• What is Powershell ?
✓ It is a simple and powerful scripting language created by Microsoft
✓ It is built on the .NET framework.
✓ Powerful tool for Automation and designed especially for the system
administrators.
✓ It is an object based
✓ The commands in the Windows PowerShell are called cmdlets, which allow
you to manage the computer from the command line
✓ Its analogue in Linux OS is called as a Bash scripting

✓ Why use PowerShell?
✓ It is both a scripting language and a command-line Shell.
✓ It can interact with a different number of technologies.
✓ Windows PowerShell allows complete access to all the types in the .NET
framework.
✓ PowerShell is object-based.
✓ Many interfaces of GUI that Microsoft designed for its various products are
front end interfaces to PowerShell.
✓ It is more secure than running VBScript or other scripting languages.
✓ It allows performing repetitive tasks more efficiently by combining multiple
commands and by writing scripts. Suppose, a system administrator wants to
create hundreds of active directory users, he can achieve this with the help of
only some PowerShell cmdlets placed in a script.
✓ Many complex and time-consuming configurations and tasks can be done in a
second with simple cmdlets of PowerShell.
Powershell Basics

How to start the Windows PowerShell
PowerShell is available in all the latest version of Windows. We need to start PowerShell by following the given steps:
1. Search for the Windows PowerShell. Select and Click.
PowerShell Window.
Powershell Basics

Powershell Basics
Windows PowerShell ISE
The Microsoft Windows PowerShell ISE is a graphical user
interface-based application and a default editor for Windows
PowerShell. ISE stands for the Integrated Scripting
Environment. It is an interface in which we can run commands
and write, test, and debug PowerShell scripts without writing
all the commands in the command-line interface.
The Integrated Scripting Environment (ISE) provides tab
completion, multiline editing, syntax coloring, context-
sensitive help, selective execution, and support for right-to-
left languages.

Powershell Basics
The ISE window of PowerShell consists of following three panes:
✓ Script Pane: This pane allows the users to create and run the
scripts. A user can easily open, edit, and run the existing scripts in
the script pane.
✓ Output Pane: This pane displays the outputs of the scripts and
the commands which are run by you. You can also clear and copy
the contents in the Output pane.
✓ Command Pane: This pane allows the users to write the
commands. You can easily execute the single or multiple-line
command in the command pane.

Powershell Basics
Enable PowerShell Scripts
When we start the PowerShell in a computer system, the default execution policy does
not allow us to execute or run the scripts.
There are four different types of execution policy in PowerShell:
✓ Restricted: In this policy, no script is executed.
✓ RemoteSigned: In this policy, only those scripts are run, which are downloaded from the Internet,
and these must be signed by the trusted publisher.
✓ Unrestricted: All the scripts of Windows PowerShell are run.
✓ AllSigned: Only those scripts can be run, which are signed by a trusted publisher
Example : Set-ExecutionPolicy Unrestricted

Powershell Basics
Run a PowerShell script
To execute the PowerShell script from the command line, follow the given steps:
1) Type the Windows PowerShell in the start menu and then open it by clicking on a result.
2) Now, execute the script by typing the full path to the script such as (C:demosample.ps1)
or if it is in current directory, type the file name followed by a backslash.
Create and Run a PowerShell Script
1. Using any editor like notepad , Visualstudio code etc.
2. Powershell ISE

Powershell Basics
What is PowerShell Cmdlet?
A cmdlet 'pronounced as a command-lets' is a lightweight command which is used in the PowerShell environment.
These are the special commands in the PowerShell environment which implements the special functions.
The cmdlets follow a 'verb-noun' pattern, such as 'set-childItem'.
Get-Process This cmdlet gets the processes which are running on local or remote computers.
Get-Service This cmdlet gets the services on local or remote computers.
Get-History This cmdlet displays a list of commands which are entered during the current session.
Restart-computer This cmdlet is used to restart the Windows operating system on local and remote computers.
Restart-Service This cmdlet stops and starts one or more services.
Get-Date
This cmdlet is used to get the current date and time.
Send-MailMessage This cmdlet is used to send an e-mail message.
Set-Date This cmdlet changes the time of the system.

Powershell Basics
Running Powershell commands and check help /Details for the commands
E.g.
Get-Help : - Displays ‘how-to’ information for commands similar man in the unix command
Get-Help -Name Get-Command –Detailed
man –Name Get-Command –Detailed
Get-Help -Name Get-Command -ShowWindow
Get-Help –Name *DNS*
Get-Help Process
Get-Command –noun “Time”
Get-Module –Listavailable

Powershell Basics
Pipelining in PowerShell
Return all the services which are Stopped
Get-Service | where-object status -eq "Stopped"
A pipeline is a series of commands connected by pipeline operators ( | ) . Each pipeline operator sends the results
of the preceding command to the next command. The output of the first command can be sent for processing as input
to the second command. And that output can be sent to yet another command
Syntax : Command-1 | Command-2 | Command-3
Return all the text file which the size is lessthan 1000 kb and in Order or the file
size
Get-ChildItem -Path *.txt |
Where-Object {$_.length -gt 1000} |
Sort-Object -Property length |
Format-Table -Property name, length
Return IPv4 Address from the Ipconfig
ipconfig.exe | Select-String -Pattern 'IPv4'

Powershell Basics
Creating Variables
What is a Variable?
A “container” that holds PowerShell “things”. Variables are Placeholders.
Use the $ to reference it in PowerShell
E.g. $Name = “Powershell”
$a = 5
$b = Get-Process | Select-Object -First $a
$b
$name = “Bangalore”
"Hello, Welcome to $name."
Tee-Object
Get expression result AND save to a variable
Get-Process ls* | Tee -Variable p

Powershell Basics
Powershell Data Types

Powershell Basics
PowerShell Operators
Operators are the building blocks of the Windows PowerShell. An operator is a character that can be used in the
commands or expressions. It tells the compiler or interpreter to perform the specific operations and produce the final
result.
1. Arithmetic Operators :
add (+), subtract (-), multiply (*), or divide (/)
2. Assignment Operators
= (Assignment operator)
+= (Addition Assignment operator)
-= (Subtraction Assignment operator)
*= (Multiplication Assignment operator)
/= (Division Assignment operator)
%= (Modulus Assignment operator)
++ (Increment Operator)
--(Decrement Operator)
E.g.
$a = 10 + 20
$b = $a / 5

Powershell Basics
PowerShell Operators
Operators are the building blocks of the Windows PowerShell. An operator is a character that can be used in the
commands or expressions. It tells the compiler or interpreter to perform the specific operations and produce the final
result.
3. Comparison Operators
-eq (Equal)
-ne (Not Equal)
-gt (Greater than)
-ge (Greater than or Equal to)
-lt (Less than)
-le (Less than or Equal to)
-like
-notlike
4. Logical Operators
-and (Logical AND)
-or (Logical OR)
-xor (Logical XOR)
-not (Logical NOT)
! (Same as Logical NOT)
E.g.
5 –gt 2
$a = 10
$b = 5
$a –gt 5
$b –le $a
$name –eq “Accenture”
"foo" –like "f*“
"bar" –notlike "B*
$a –gt 10 –AND $a –le 50
$a –eq 10 –OR $a –eq 50

Powershell Basics
PowerShell Operators Cont..
1. Redirection Operators
The Redirection operators are used in PowerShell to redirect the output from the PowerShell
console to text files.
1. >
This operator is used to send the specified stream to the specified text file. The following
statement is the syntax to use this operator
Syntax : Command n> Filename
E.g. Get-childitem > YourFile.txt
2. >>
This operator is used to append the specified stream to the specified text file.
The following statement is the syntax to use this operator:
Syntax : Command n>> Filename
E.g. Get-help >> k.txt

Powershell Basics
1. Split and Join Operators
The Split and Join operators are used in PowerShell to divide and combine the substrings.
-Join Operator
The -Join operator is used in PowerShell to
combine the set of strings into a single string.
The strings are combined in the same order in
which they appear in the command.
E.g. - Join "windows","Operating","System"
The following two statements are the syntax
to use the Join operator:
-Join <String>
<String> -Join <Delimiter>
-Split Operator
The -Split operator is used in PowerShell to divide the one or
more strings into the substrings.
Syntax:
1.-Split <String>
2.-Split (<String[]>)
3.<String>-Split <Delimiter> [,<Maxsubstrings>
[,"<Options>"]]
1.<String> -Split {<ScriptBlock>} [,<Max-substrings>]
E.g.
$a = "a b c d e f g h"
-split $a

Powershell Basics
Using Arrays and Hashtables
A data structure that is designed to store a collection of items. The items can be the same type or different
types.
Any comma-separated list is an array
Initializing an empty array
We can initialize an empty array by using the
following syntax:
$a = 3,5,9
@arrayName = @()
Array

Powershell Basics
Using Arrays and Hashtables
Manipulation of an Array
We can change the value of specific index value in an array by
specifying the name of the array and the index number of
value to change.
$p[2]=20
$a = 3,5,9
Accessing Array Elements
You can display all the values of an array on the PowerShell console by
typing the name of an array followed by a dollar ($) sign.
$p or $p[1] or $p[2..5]

Powershell Basics
PowerShell Hast table
The PowerShell Hashtable is a data structure that stores one or more key/value pairs. It is also known as the
dictionary or an associative array. The hashtable name is the key
Syntax : $variable_name = @{ <key1> = <value1> ; < key2> = <value2> ; ..... ; < keyN> = <valueN>;}
The following statement is the syntax to create an ordered dictionary:
$variable_name = [ordered] @{ < key1> = <value1> ; < key2> = <value2> ; ..... ; < keyN> = <valueN>;}
$variablename = @{}
$student = @{ name = "Abhay" ; Course = "BCA" ; Age= 19 }
Display a Hash table
$Student

Powershell Basics
Controlling the flow of PowerShell Functions
IF .. ELSE Statement
When we need to execute the block of statements only when the specified condition is true, use an If
statement.
f(test_expression)
{
Statement-1
Statement-2.......
Statement-N
}
else
{
Statement-1
Statement-2.......
Statement-N
}
$a=15
$c=$a%2
if($c -eq 0)
{
echo "The number is even"
} else
{
echo "The number is Odd"
}

Powershell Basics
Switch Statement Syntax
# Syntax
Switch (<expression>) {
<condition1> { <code> }
}
# Variable
$number = 3
# Example Syntax
Switch ($number) {
5 { Write-Host "Number equals 5" }
Default { Write-Host "Number is not equal to 5, 10, or 20"}
}

Powershell Basics
Do-While Loop
The Do-While loop is a looping structure in which a condition is evaluated after executing the statements. This loop is
also known as the exit-controlled loop
Syntax
The following block shows the syntax of Do-while loop:
Do
{
Statement-1
Statement-2
Statement-N
} while( test_expression)
$i=1
do
{
echo $i
$i=$i+1
} while($i -le 10)

Powershell Basics
While loop
It is an entry-controlled loop. This loop executes the statements in a code of block when a specific condition evaluates to
True.
Syntax of While loop
while(test_expression)
{
Statement-1
Statement-2
Statement-N
}
while($count -le 5)
{
echo $count
$count +=1
}

Powershell Basics
For Loop
The For loop is also known as a 'For' statement in a PowerShell. This loop executes the statements in a code of block
when a specific condition evaluates to True. This loop is mostly used to retrieve the values of an array.
Syntax of For loop
for (<Initialization>; <Condition or Test_expression>; <Repeat>)
{
Statement-1
Statement-2
Statement-N
}
Examples
for($x=1; $x -lt 10; $x=$x+1)
{
echo $x
}

Powershell Basics
ForEach loop
The Foreach is a keyword which is used for looping over an array or a collection of objects, strings, numbers, etc.
Mainly, this loop is used in those situations where we need to work with one object at a time.
Syntax
Foreach($<item> in $<collection>)
{
Statement-1
Statement-2
Statement-N
}
$Array = 1,2,3,4,5,6,7,8,9,10
foreach ($number in $Array)
{
echo $number
}

Powershell
Functions ,
Exception Handling,
Unit Testing with Pester

Powershell Basics
PowerShell Functions
• A function is a list of PowerShell statements whose name is assigned by the user
• Functions are the building block of Powershell scripts
• Reusable throughout the script, when we need to use the same code in more than one script, then we use
a PowerShell function
• Can contain variables, parameters, statements and also can call other functions
• When we execute a function, we type the name of a function.
Functions with Arguments and Parameters
Argument
• Arguments are not specified within a function
• Arguments are simply populated by passing values to function at the point of excuction
• Values are retrieved by using ID
Parameter:
• A Parameter is a varibale defined in a funciton
• Parameters have properties
• Parameters can be Mandatory or optional..

Powershell Basics
Syntax
function <name> [([type]$parameter1[,[type]$parameter2])]
{
param([type]$parameter1 [,[type]$parameter2])
dynamicparam {<statement list>}
begin {<statement list>}
process {<statement list>}
end {<statement list>}
}

Powershell Basics
#Create Function without Arguments
Function Find-SquareRoot()
{
$number = Read-Host “Enter any positive Number “
$number =[convert]::ToInt32($number)
return $number * $number
}
Find-SquareRoot
#Creating Function with Arguments
Function Find-SquareRoot()
{
$number1 = $args[0]
$number2 = $args[1]
$result =[convert]::ToInt32($number1) *
[convert]::ToInt32($number2)
return $result
}
Find-SquareRoot 25 2

Powershell Basics
#Create function with Variable
Function Find-SquareRoot($num)
{
$number =[convert]::ToInt32($num)
return $number * $number
}
Find-SquareRoot 20
#Create function with Variable
function add ([int]$num1, [int]$num2)
{
$c = $num1 + $num2
echo $c
}
#invoking Function
Add 1 2

Powershell Basics
#Creating Function with Parameter
Function Find-Capital()
{
Param(
[Parameter(Mandatory=$true)]
[string]$Country
)
if($Country -eq "India")
{
Write-Host "The Capital of $Country is New Delhi" -ForegroundColor Green
}
else
{
Write-Host "Sorry, Capital not Found!!" -ForegroundColor Red
}
}
Find-Capital -Country "India"

Powershell Basics
Comment PowerShell Scripts
Single-Line PowerShell Comments Begins with the number/hash character (#).
Everything on the same line after it is ignored by PowerShell Block Comments / Multiline Comments Comment
blocks in PowerShell begin with "<#" and end with "#>“

Powershell Basics
Exception Handling in Powershell
An Exception is like an event that is created when normal error handling can not deal with the issue.
Trying to divide a number by zero or running out of memory are examples of something that will
create an exception
To create our own exception event, we throw an exception with the throw keyword.
function Do-Something
{
throw "Bad thing happened"
}

Powershell Basics
Try/Catch
The way exception handling works in PowerShell (and many other languages) is that you first try a
section of code and if it throws an error, you can catch it
Syntax :
try
{
Do-Something
}
catch
{
Write-Output "Something threw an exception"
}
Finally
{
# Execute the final block
}
try
{
Do-Something -ErrorAction Stop
}
catch
{
Write-Output "Something threw an exception or used Write-
Error"
}

Powershell Basics
Catching typed exceptions
You can be selective with the exceptions that you catch.
Exceptions have a type and you can specify the type of exception you want to catch.
try
{
Do-Something -Path $path
}
catch [System.IO.FileNotFoundException]
{
Write-Output "Could not find $path"
}
catch [System.IO.IOException]
{
Write-Output "IO error with the file: $path"
}

Powershell Unit Testing with Pester
PowerShell own a Unit testing framework. Its name is Pester, it’s the ubiquitous test and mock framework for
PowerShell. It’s a Domain Definition Language and a set of tools to run unit and acceptance test.
Installing Pester
Even if Pester is now installed by default on Windows 10, it’s better to update it to the latest version (now in
4.8.x, soon in 5.x).
Pester can be installed on Windows PowerShell (even on old version) and on PowerShell Core
Install-module -name Pester
You may need to use the force parameter if another is already installed
Install-Module Pester -Force –SkipPublisherCheck
Update-Module Pester –Force
To verify whether the Pester Module Installed
Get-Module -Name Pester -ListAvailable

The basic
A test script starts with a Describe. Describe block create the
test container where you can put data and script to perform
your tests. Every variable created inside a describe block is
deleted at the end of execution of the block.
Describe {
# Test Code here
}
Describe "test" {
It "true is not false" {
$true | Should -Be $true
}
}
Describe "Test Calculate Method"{
Context "Adding Numbers"{
It "Should be 5"{
$result = Add-Number 2 3
$result | Should -Be 5
}
}
}

Tests inside a describe block can be grouped into a Context.
Context is also a container and every data or variable created
inside a context block is deleted at the end of the execution of
the context block
Context and Describe define a scope.
Describe -tag "SQL" -name "Sqk2017" {
# Scope Describe
Context "Context 1" {
# Test code Here
# Scope describe 1
}
Context "Context 2" {
# Test code Here
# Scope describe 2
}
}
Providing Context
Often a Describe block can contain many
tests. When there are quite a few, it can be
helpful to group related tests into blocks. This
is where the Context function comes into
play. You can think of a Context as a sub-
Describe, it will provide an extra level in the
output.

Describe 'Grouping using Context' {
Context 'Test Group 1 Boolean Tests' {
It 'Should be true' { $true | Should -Be $true }
It 'Should be true' { $true | Should -BeTrue }
It 'Should be false' { $false | Should -Be $false }
It 'Should be false' { $false | Should -BeFalse }
}
Context 'Test Group 2 - Negative Assertions' {
It 'Should not be true' { $false | Should -Not -BeTrue }
It 'Should be false' { $true | Should -Not -Be $false }
}
Context 'Test Group 3 - Calculations' {
It '$x Should be 42' {
$x = 42 * 1
$x | Should -Be 42
}
It 'Should be greater than or equal to 33' {
$y = 3 * 11
$y | Should -BeGreaterOrEqual 33
}
It 'Should with a calculated value' {
$y = 3
($y * 11) | Should -BeGreaterThan 30
}
}
Context 'Test Group 4 - String tests' {
$testValue = 'ArcaneCode'
# Test using a Like (not case senstive)
It "Testing to see if $testValue has arcane" {
$testValue | Should -BeLike "arcane*"
}
# Test using cLike (case sensitive)
It "Testing to see if $testValue has Arcane" {
$testValue | Should -BeLikeExactly "Arcane*"
}
}
Context 'Test Group 5 - Array Tests' {
$myArray = 'ArcaneCode', 'http://arcanecode.red', 'http://arcanecode.me'
It 'Should contain ArcaneCode' {
$myArray | Should -Contain 'ArcaneCode'
}
It 'Should have 3 items' {
$myArray | Should -HaveCount 3
}
}
}

It Block
To create a test with Pester we simply use
the keyword It. The It blocks contain the test
script. This script should throw an exception.
It blocks need to have an explicit description
It "return the name of something" and a
script block. The description must be unique
in the scope (Describe or Context).
It description can be static or dynamically
created (ie: you can use a variable as
description as long as the description is
unique)
There are several assertions:
Assertions Descriptions
Be Compare the 2 objects
BeExactly Compare the 2 objects in case sensitive mode
BeGreaterThan The object must be greater than the value
BeGreaterOrEqual The object must be greater or equal than the value
BeIn test if the object is in array
BeLessThan The object must be less than the value
BeLessOrEqual The object must be less or equal than the value
BeLike Perform a -li comparaison
BeLikeExactly Perform a case sensitive -li comparaison
BeOfType Test the type of the value like the -is operator
BeTrue Check if the value is true
BeFalse Check if the value is false
HaveCount The array/collection must have the specified ammount of value
Contain The array/collection must contain the value, like the -contains operator
Exist test if the object exist in a psprovider (file, registry, ...)
FileContentMatch Regex comparaison in a text file
FileContentMatchExactly Case sensitive regex comparaison in a text file
FileContentMatchMultiline Regex comparaison in a multiline text file
Match RegEx Comparaison
MatchExactly Case sensitive RegEx Comparaison
Throw Check if the ScriptBlock throw an error
BeNullOrEmpty Checks if the values is null or an empty string

write and run Pester tests
You can virtually run pester in any PowerShell file but by
convention, it’s recommended to use a file named
xxx.tests.ps1. One per PowerShell file in your solution. If you
have one file per function it mean one pester .tests.ps1.
You can place pester files in the same folder as your source
code or you can use a tests folder at the root of the repository.
Code Coverage
Code coverage measure the degree to which your code is
executed by your tests. The measure is expressed in a
percentage.
invoke-pester -script .Calculate.Test.ps1 -CodeCoverage .calculate.psm1

BeforeAll {
# your function
function Get-Planet ([string]$Name='*')
{
$planets = @(
@{ Name = 'Mercury' }
@{ Name = 'Venus' }
@{ Name = 'Earth' }
@{ Name = 'Mars' }
@{ Name = 'Jupiter' }
@{ Name = 'Saturn' }
@{ Name = 'Uranus' }
@{ Name = 'Neptune' }
) | foreach { [PSCustomObject]$_ }
$planets | where { $_.Name -like $Name }
}
}
# Pester tests
Describe 'Get-Planet' {
It "Given no parameters, it lists all 8 planets" {
$allPlanets = Get-Planet
$allPlanets.Count | Should -Be 8
}
Context "Filtering by Name" {
It "Given valid -Name '<Filter>', it returns '<Expected>'" -TestCases @(
@{ Filter = 'Earth'; Expected = 'Earth' }
@{ Filter = 'ne*' ; Expected = 'Neptune' }
@{ Filter = 'ur*' ; Expected = 'Uranus' }
@{ Filter = 'm*' ; Expected = 'Mercury', 'Mars' }
) {
param ($Filter, $Expected)
$planets = Get-Planet -Name $Filter
$planets.Name | Should -Be $Expected
}
It "Given invalid parameter -Name 'Alpha Centauri', it returns `$null" {
$planets = Get-Planet -Name 'Alpha Centauri'
$planets | Should -Be $null
}
}
}

Powershell Reference
Unit testing in PowerShell, introduction to Pester - DEV Community
Run Pester tests on Azure Pipelines – Cloud Notes
GitHub - pester/Pester: Pester is the ubiquitous test and mock framework for PowerShell.
Quick Start | Pester (pester-docs.netlify.app)

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