#100DaysOfCloudDevOps Challenge — Day 07 — Powershell

What is Powershell?

PowerShell is a tool that helps automate tasks and manage systems. It includes a command-line interface (where you type commands), a scripting language (to write custom tasks), and a framework to manage configurations. PowerShell works on Windows, Linux, and macOS.

Install PowerShell on Windows, Linux, and macOS: https://learn.microsoft.com/en-us/powershell/scripting/install/installing-powershell?view=powershell-7.5

The three core cmdlets in PowerShell

• Get-Help

• Get-Command

• Get-Member

People often ask me, “How do you determine the commands in PowerShell?” Two essential tools for exploring and understanding PowerShell commands are Get-Help and Get-Command.

Key Aspects of PowerShell

Cmdlets - Basic System Commands

PowerShell cmdlets help manage processes, files, and system information.

📌 Example: Search for a module (e.g., Azure)

# This will search the PowerShell Gallery for any modules that match Az, which is commonly used for managing Azure resources.
Find-Module -Name "Az"

📌 Example: Search for modules related to AWS

# This will return the AWS module to manage AWS resources in PowerShell.
Find-Module -Name "AWSPowerShell"

📌 Example: Check running processes

Get-Process | Select-Object -First 10  # Show first 10 running processes

📌 Example: Find a specific process (e.g., Safari)

Get-Process -Name "Safari"

📌 Example: Kill an unresponsive app (e.g., Safari)

Stop-Process -Name "Safari" -Force

📌 Example: Get the current system date and time

Get-Date

📌 Example: Get the user current timezone

Get-TimeZone

Pipelines - Data Filtering & Sorting

Pipelines allow passing output from one command to another.

📌 Example: Find large files in a folder

Get-ChildItem -Path ~/Documents -Recurse | Where-Object { $_.Length -gt 10MB }

📌 Example: List the top 5 CPU-consuming processes

Get-Process | Sort-Object CPU -Descending | Select-Object -First 5

📌 Example: Find all .log files and delete them

Get-ChildItem -Path ~/Documents -Filter "*.log" | Remove-Item -Force

Objects - Structured Data Handling

PowerShell deals with objects, not just text.

📌 Example: Get system information as an object

$systemInfo = system_profiler SPHardwareDataType
Write-Output $systemInfo

📌 Example: Extract specific details from objects

(system_profiler SPHardwareDataType | ConvertFrom-Csv).ModelName

📌 Example: Display disk space usage

Get-PSDrive -PSProvider FileSystem

Scripting - Automate Repetitive Tasks

📌 Example: Create a script to clean temporary files

1. Open Terminal and create a new PowerShell script:

code ~/cleanup.ps1

2. Add this code inside the script:

$folder = "~/Downloads"
Get-ChildItem -Path $folder -Recurse | Where-Object { $_.LastWriteTime -lt (Get-Date).AddDays(-30) } | Remove-Item -Force
Write-Output "Old files deleted!"

3. Save and run:

pwsh ~/cleanup.ps1

📌 Example: Backup files to an external drive

Copy-Item -Path ~/Documents/* -Destination /Volumes/BackupDrive -Recurse

📌 Example: Script to check disk space and send an alert

$freeSpace = (Get-PSDrive -Name C).Free
if ($freeSpace -lt 10GB) {
    Write-Host "Warning: Low disk space!"
} else {
    Write-Host "Disk space is sufficient."
}

Remoting - Connect to Remote Systems

PowerShell can manage remote machines.

📌 Example: SSH into a Linux Server

Enter-PSSession -HostName "user@yourserver.com" -UseSSH

📌 Example: Run a command on a remote machine

Invoke-Command -HostName "user@yourserver.com" -UseSSH -ScriptBlock { Get-Date }

Modules - Extend PowerShell Features

Modules add new commands.

📌 Example: Install and use a module

Install-Module -Name PowerShellGet -Scope CurrentUser -Force
Import-Module PowerShellGet

📌 Example: Get a list of installed modules

Get-Module -ListAvailable

Automation - Schedule and Automate Tasks

PowerShell automates system administration, cloud, and DevOps tasks.

📌 Example: Automatically restart a service if it’s stopped

$service = Get-Service -Name "Spooler"
if ($service.Status -ne 'Running') {
    Start-Service -Name "Spooler"
    Write-Host "Service restarted."
}

📌 Example: Backup files every day using Task Scheduler

$Action = New-ScheduledTaskAction -Execute "PowerShell.exe" -Argument "-File C:\Scripts\Backup.ps1"
$Trigger = New-ScheduledTaskTrigger -Daily -At 3am
Register-ScheduledTask -TaskName "DailyBackup" -Action $Action -Trigger $Trigger

Some PowerShell Commands

The basics

✅ Goal: Get comfortable with basic cmdlets.

1. Open PowerShell and run the following commands:

Get-Process       # List running processes
Get-Service       # List system services
Get-Date          # Display current date and time
Get-Command       # List available commands
Get-Help Get-Process  # Get help on a command

2. Challenge: Use PowerShell to find your system’s hostname and IP address.

hostname
Get-NetIPAddress

Work with Files & Folders

✅ Goal: Learn how to create, modify, and delete files.

1. Create a new folder and a text file:

New-Item -ItemType Directory -Path "C:\PowerShellPractice"
New-Item -ItemType File -Path "C:\PowerShellPractice\log.txt"

2. Write text into the file:

Set-Content -Path "C:\PowerShellPractice\log.txt" -Value "This is a test log."

3. Append more text:

Add-Content -Path "C:\PowerShellPractice\log.txt" -Value "Appending new log entry."

4. Read the file:

Get-Content -Path "C:\PowerShellPractice\log.txt"

5. Challenge: List all .txt files in C:\PowerShellPractice and delete them.

Get-ChildItem -Path "C:\PowerShellPractice" -Filter "*.txt" | Remove-Item

Automate User & Process Management

✅ Goal: Manage processes and system users.

1. Find a running process (e.g., Notepad) and stop it:

Get-Process -Name notepad
Stop-Process -Name notepad -Force

2. List all currently logged-in users:

Get-WmiObject -Class Win32_ComputerSystem | Select-Object UserName

3. Challenge: Check if “notepad.exe” is running every 10 seconds, and stop it if found.

while ($true) {
    if (Get-Process -Name notepad -ErrorAction SilentlyContinue) {
        Stop-Process -Name notepad -Force
        Write-Output "Notepad was running and has been stopped."
    }
    Start-Sleep -Seconds 10
}

Automate System Tasks with Schedules

✅ Goal: Schedule a script to run automatically.

1. Create a script that logs the system uptime every hour.

(Get-Date).ToString() + " Uptime: " + (Get-Uptime) | Out-File -Append "C:\PowerShellPractice\uptime.log"

2. Schedule the script to run every hour using Task Scheduler:

$Action = New-ScheduledTaskAction -Execute "PowerShell.exe" -Argument "-File C:\PowerShellPractice\uptime.ps1"
$Trigger = New-ScheduledTaskTrigger -Hourly -At (Get-Date).AddHours(1)
Register-ScheduledTask -TaskName "Log System Uptime" -Action $Action -Trigger $Trigger

Manage Cloud Resources (Azure)

✅ Goal: Use PowerShell to manage cloud resources.

📌 Prerequisite: Install Az PowerShell module.

Install-Module -Name Az -Scope CurrentUser -AllowClobber -Force

1. Login to Azure:

Connect-AzAccount

2. Create a new Azure resource group:

New-AzResourceGroup -Name "MyResourceGroup" -Location "EastUS"

3. Challenge: List all VMs in your Azure subscription.

Get-AzVM

Write a Simple PowerShell Script

✅ Goal: Automate a repetitive task.

1. Open Notepad and save the following script as C:\PowerShellPractice\backup.ps1:

$source = "C:\Users\Public\Documents"
$destination = "D:\Backup"

if (-Not (Test-Path $destination)) {
    New-Item -ItemType Directory -Path $destination
}

Copy-Item -Path "$source\*" -Destination $destination -Recurse
Write-Output "Backup completed at $(Get-Date)" | Out-File -Append "$destination\backup.log"

2. Run the script in PowerShell:

PowerShell -File "C:\PowerShellPractice\backup.ps1"

3. Challenge: Modify the script to zip the backup folder after copying.

✅ Goal: For macOS and Linux, create a user and set permissions using shell commands in PowerShell.

# Define user details
$userName = "newuser"
$password = "P@ssw0rd"
$group = "staff"  # For macOS/Linux, you can use groups like 'staff'
$folderPath = "/Users/Public/Documents"
$permission = "rw"  # read/write permissions

# Create new user (Linux/macOS)
sudo dscl . -create /Users/$userName
sudo dscl . -create /Users/$userName UserShell /bin/bash
sudo dscl . -create /Users/$userName RealName "New User"
sudo dscl . -create /Users/$userName Password $password
sudo dscl . -append /Groups/$group GroupMembership $userName

# Set folder permissions
sudo chmod -R u+rw $folderPath  # Give user read/write permission
sudo chown -R $userName:$group $folderPath  # Change folder ownership

# Output success message
Write-Host "User $userName created and permissions set!"

DevOps - Run PowerShell in CI/CD Pipeline

✅ Goal: Run PowerShell in a DevOps pipeline.

1. In Azure DevOps, GitHub Actions, or GitLab CI/CD, add a PowerShell script step.

Example (Azure DevOps YAML):

steps:
  - task: PowerShell@2
    inputs:
      targetType: 'inline'
      script: |
        Write-Host "Starting deployment..."
        Get-Date

3. Challenge: Modify the pipeline to deploy an Azure VM using PowerShell.

Whether you’re a beginner or an expert, PowerShell provides tools to make system administration and cloud management a breeze. Start with simple commands like Get-TimeZone or create automated tasks such as backing up files daily.

Ready to dive in? Explore the full capabilities of PowerShell with a simple installation on your machine, and try out the practical examples provided. Let PowerShell simplify and automate your workflow today!

Start your PowerShell journey here.

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Find the GitHub repo here.

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