Skip to main content

Effective Windows PowerShell free ebook

A late Christmas gift for everyone,  Keith Hill has turned a set of blog posts into an 61 pages long PowerShell ebook.

Download your own copy here.

 

Table of content:

  • Introduction
  • Item 1: Four Cmdlets that are the Keys to Discovery within PowerShell
    • Key #1: Get-Command
    • #2: Get-Help
    • Key #3: Get-Member
    • Key #4: Get-PSDrive
    • PowerShell 2.0 Update
  • Item 2: Understanding Output
    • Output is Always a .NET Object
    • Function Output Consists of Everything That Isn't Captured
    • Other Types of Output That Can't Be Captured
  • Item 3: Know What Objects Are Flowing Down the Pipeline
  • Item 4: Output Cardinality - Scalars, Collections and Empty Sets - Oh My!
    • Working with Scalars
    • Working with Collections
    • Working with Empty Sets
  • Item 5: Use the Objects, Luke. Use the Objects!
  • Item 6: Know Your Output Formatters
  • Item 7: Understanding PowerShell Parsing Modes
  • Item 8: Understanding ByPropertyName Pipeline Bound Parameters
  • Item 9: Understanding ByValue Pipeline Bound Parameters
  • Item 10: Error Handling
    • Terminating Errors
    • Non-terminating Errors
    • Error Variables
    • Working with Non-Terminating Errors
    • Handling Terminating Errors
    • Trap Statement
    • Try / Catch / Finally
  • Item 11: Regular Expressions - One of the Power Tools in PowerShell
    • PowerShell 2.0 Update
  • Item 12: Comparing Arrays
  • Item 13: Use Set-PSDebug -Strict In Your Scripts – Religiously
    • PowerShell 2.0 Update
  • Item 14: Commenting Out Lines in a Script File
    • PowerShell 2.0 Update
  • Item 15: Using the Output Field Separator Variable $OFS

Popular posts from this blog

Podman– Command execution failed with exit code 125

After updating WSL on one of the developer machines, Podman failed to work. When we took a look through Podman Desktop, we noticed that Podman had stopped running and returned the following error message: Error: Command execution failed with exit code 125 Here are the steps we tried to fix the issue: We started by running podman info to get some extra details on what could be wrong: >podman info OS: windows/amd64 provider: wsl version: 5.3.1 Cannot connect to Podman. Please verify your connection to the Linux system using `podman system connection list`, or try `podman machine init` and `podman machine start` to manage a new Linux VM Error: unable to connect to Podman socket: failed to connect: dial tcp 127.0.0.1:2655: connectex: No connection could be made because the target machine actively refused it. That makes sense as the podman VM was not running. Let’s check the VM: >podman machine list NAME         ...

Cache stampede: when our cache turned against us

While investigating some performance issues, we ran into an ASP.NET Core API that cached a fairly expensive aggregation query for 60 seconds. Under normal load, that was fine: one request rebuilds the cache, everyone else reads from it. Under peak load, dozens of requests would arrive in that same expiry window, all see a cache miss, and all fire the same expensive query in parallel. The database didn't like that. That was the moment when our caching layer stopped helping and started hurting. A burst of requests comes in at the same time, all miss the cache, and all go hammer the database or the downstream API at once. That's a cache stampede . The cache was supposed to protect our backend, and for a few hundred milliseconds it did the opposite. Why this happens IMemoryCache.GetOrCreate (and its async sibling) looks like it protects you, but it doesn't add any locking on its own. Look at the naive version: public async Task<Report> GetReportAsync(string key) ...

VS Code Planning mode

After the introduction of Plan mode in Visual Studio , it now also found its way into VS Code. Planning mode, or as I like to call it 'Hannibal mode', extends GitHub Copilot's Agent Mode capabilities to handle larger, multi-step coding tasks with a structured approach. Instead of jumping straight into code generation, Planning mode creates a detailed execution plan. If you want more details, have a look at my previous post . Putting plan mode into action VS Code takes a different approach compared to Visual Studio when using plan mode. Instead of a configuration setting that you can activate but have limited control over, planning is available as a separate chat mode/agent: I like this approach better than how Visual Studio does it as you have explicit control when plan mode is activated. Instead of immediately diving into execution, the plan agent creates a plan and asks some follow up questions: You can further edit the plan by clicking on ‘Open in Editor’: ...