Basic programming syntax in PowerShell for C# developers

ByAnkush Jain| Last Updated On Thursday, Aug 02, 2018

PowerShell

Disclaimer: I am a consultant at Amazon Web Services, and this is my personal blog. The opinions expressed here are solely mine and do not reflect the views of Amazon Web Services (AWS). Any statements made should not be considered official endorsements or statements by AWS.

Recently I started working on PowerShell as I was working on C# for a long time. Initially, it took me a while to get familiar with the PowerShell syntaxes. That’s why I thought to put all my google searches over here in this single post. I hope this will help you during your transition period from C# to PowerShell.

How to use for loop in PowerShell?

# declare & initialize an array
[string[]] $names = @("Ankush", "Virat", "Sachin", "MS Dhoni")

# call for loop
For ($i=0; $i -lt $names.count ; $i++) {

    [string]$playerName =  $names[$i]

    Write-Output $playerName
}

How to use foreach in PowerShell?

# declare & initialize an array
[string[]] $names = @("Ankush", "Virat", "Sachin", "MS Dhoni")

# call foreach
Foreach ($playerName in $names)
{   
    Write-Output $playerName
}

How to use if block in PowerShell?

[bool] $result = $true

if($result){
    Write-Output "Success"
}

Declare an array in PowerShell?

# declare & initialize an array
[string[]] $names = @("Ankush", "Virat", "Sachin", "MS Dhoni")

How to check if array contains a value in PowerShell?

# declare & initialize an array
[string[]] $names = @("Ankush", "Virat", "Sachin", "MS Dhoni")

if($names.Contains("Ankush")){
    Write-Output "Yes Ankush Exists"
}

How to add an item in PowerShell?

# declare & initialize an array
[string[]] $names = @("Ankush", "Virat", "Sachin", "MS Dhoni")

# add item in array
$names += "Ishant"

How to use less than, equals to etc. operators in PowerShell?

$i = 4
$j = 8

# use -eq for equal operator
Write-Output ($i -eq $j)

# use -le for less than or equal operator
Write-Output ($i -le $j)

How to save a JSON object to a file in PowerShell?

[string]$pathToSave =  "C:\Users\ankushjain01\Desktop\"

$apiResult =  Invoke-RestMethod -Uri "http://example.com/getusers" -Method Get -ContentType "application/json"

# code to save json
$apiResult | ConvertTo-Json -depth 100 | Set-Content "$pathToSave\users.json"

How to call a REST API using PowerShell?

# physical path to save json result
[string]$pathToSave =  "C:\Users\ankushjain01\Desktop\"

# Base64-encodes the Personal Access Token (PAT) appropriately
[string]$base64AuthInfo = [Convert]::ToBase64String([Text.Encoding]::ASCII.GetBytes(("{0}:{1}" -f $user,$password)))

# this method invokes rest api & downloads it's result into json object
$apiResult =  Invoke-RestMethod -Uri "http://example.com/getusers" -Method Get -ContentType "application/json" -Headers @{Authorization=("Basic {0}" -f $base64AuthInfo)}

# code to save json
$apiResult | ConvertTo-Json -depth 100 | Set-Content "$pathToSave\users.json"