Learn to build powershell script (for busy programmers)

Feb 18, 2022

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Multi-line comment

<# …. #>

Print message in console

Write-Host “hello world”

Variables

#variable of type String 
$name=""

#variable of type Int32 (Integer)
$id=10

#variable of type Hashtable
$map = @{name=”trees”;color=”green”} 

#variable of type array
$array = "lion","tiger","wolf"

Print value of a variable in console

Access a property from hashtable

Add a property to an hashtable

Remove a property from hashtable

List all keys in an Hashtable

Iterate a Hashtable

Iterate an array

How to find the datatype of variables? using GetType() function. Below is an example on how to use GetType()

Type-conversion of variable

#convert String to Dictionary or Json
$responseBody = $httpResponse | ConvertFrom-Json

#convert ,(comma) separated String to Array of Strings
$stringArray = $commaString.Split(",")

#convert String to Hashtable
$hashTable = Invoke-Expression $hashString

Invoke a restApi endpoint with Httpmethod Get

# $httpResponse will be of type String
$httpResponse = Invoke-WebRequest -Uri https://domain.com/api/users -Method Get

#convert String to Dictionary or Json
$responseBody = $httpResponse | ConvertFrom-Json

#print the json object i.e $responseBody
Write-Host "responseBody $responseBody" 

#fetch a country name from JSON object
$countryName = $responseBody."Country Name"

#print all the keys and values from the JSON object
foreach($key in  $responseBody.PsObject.Properties.name){
        Write-Host "key:: $key value:: " $responseBody.$key 
}

Pass Header along with the `Get` request

$httpResponse = Invoke-WebRequest -Uri https://cricscore -Headers @{ 'app-name' ='cocofruit'}

User-defined function without arguments

function MyFun{
    return "pluto"
}

# $retval will hold "pluto"
$retval = MyFun

User-defined function with single argument

function MyFun {
    param (
        $osName
    )
    return $osName
}
$retval = MyFun("ubuntu")

User-defined function with multiple arguments

function MyFun{
    param(
        $country,
        $state,
        $city
    )
    Write-Host "country: $country :state: $state :city: $city "
}
MyFun "India" "Tamilnadu" "Madurai"

Add a newline character with-in a string

$sentence="curious the `r`n lazy frog"

Send email

$fromEmail = "admin@gmail.com"
$toEmail = "divine@gmail.com","fish@gmail.com","seal@gmail.com"

$attachmentFile = "filename.html"
New-Item $attachmentFile -ItemType File

Add-Content $attachmentFile "Dummy content within attachment"

Send-MailMessage -To $toEmail -From $fromEmail -Subject "REPORT" -Body "emailBody" -BodyAsHtml -Priority High -SmtpServer "mailhost3" -Attachments $attachmentFile

Array


$data = @(
    'Zero'
    'One'
    'Two'
    'Three'
)
$data += 'four'

Write-Host "$data”
Write-Host $data.count

foreach ( $node in $data )
{
    "Item: [$node]"
}

Array of objects

$data = @(
    [pscustomobject]@{FirstName='Kevin';LastName='Marquette'}
    [pscustomobject]@{FirstName='John'; LastName='Doe'}
)

#$data = @()

#Write-Host $data[0]

#Write-Host $data[0].FirstName
$data +=  [pscustomobject]@{FirstName='Tiger1'; LastName='cream'}
$data +=  [pscustomobject]@{FirstName='ice'; LastName='blood'}
foreach($person in $data)
{
   Write-Host $person.FirstName
}

Sort the above array of objects by Firstname

$sorted = $data | Sort-Object  -Property FirstName

foreach($sor in $sorted)
{
    Write-Host $sor.FirstName
}

This blog will be updated …

Arrays

Cocofruit

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