PowerShell Pop Quiz

I'm always looking for ways to help teach PowerShell and the other day I thought why not have PowerShell teach you itself? I have created a PowerShell script that dynamically generates a quiz on cmdlets and functions installed on your computer. In short the quiz question shows you a command synopsis and then presents a menu of possible answers. You select the answer. Given the verb-noun pattern of command names this *should* be easy, but you might be surprised.

Right now, the quiz comes in a stand-alone script. At some point I'll most likely add it to my PSTeachingTools module which you can install from the PowerShell Gallery. The script has help so after you download it you can get it:

help C:\scripts\PSquiz.ps1 -full

By default the script will find all cmdlets and functions from modules installed on your computer that have a properly defined synopsis. I've tried to include some filtering to handle buggy commands or those that have no help. You can also exclude one or more modules and wild cards are allowed. Or, you can specify a specific module. After the script builds a cache of commands it autogenerates a question and prompts you for an answer:

If you answer wrong, the script will display the correct answer. To continue with another question, press any key. The script will keep track of your progress and when you eventually quit, display a color coded summary result.

For now, you can find the script here.

#requires -version 5.0

#PSQuiz.ps1

<#
.Synopsis
Run a PowerShell quiz
.Description
Use this script to test your knowledge of PowerShell commands, which given the Verb-Noun naming pattern should be pretty easy.

The default behavior is to use all cmdlets and functions from installed modules with an option to exclude an array of module names. Wildcards are allowed. You also have the option to specify a single module for testing.
.Example
PS C:\> c:\scripts\PSQuiz.ps1

PowerShell Pop Quiz

Given this short cmdlet description:

 Creates a new System.Windows.Markup.RoutedEventConverter

 What command would you use?

  [1]   Invoke-CauScan
  [2]   Clear-Tpm
  [3]   Remove-WindowsCapability
  [4]   Get-IscsiTargetServerSetting
  [5]   New-RoutedEventConverter

Select a menu choice [1-5]: 5

You are Correct!!

Do you want another question? Press any key to continue or Q to quit: q
Your scored 1 correct out of 1 [100.00 %]
.Example
PS C:\> c:\scripts\PSQuiz.ps1 -module Hyper-V

Launch the quiz but only use commands from the Hyper-V module.

.Example
PS C:\> c:\scripts\PSQuiz.ps1 -exclude ISE,WPK,my*

Launch the quiz using all modules except ISE, WPK and any modules that start with 'my'.
.Link
Get-Help
.Link
Get-Command
.Notes
Version 0.9

Learn more about PowerShell:
Essential PowerShell Learning Resources



#>
[cmdletbinding(DefaultParameterSetName = "all")]
Param(
    [Parameter(ParameterSetName = "single")]    
    [ValidateScript( {Get-Module $_ -list})]
    #You can specify a single module for testing. The default is all modules.
    [string]$ModuleName,
    [Parameter(ParameterSetName = "all")]
    #Enter a comma separated list of module names to ignore. You can use wildcards.
    [string[]]$Exclude,
    #This is used to indicate a continuing test. You should never need to use this parameter.
    [switch]$NextQuestion
)

Clear-Host
Write-Verbose "Starting $($myinvocation.MyCommand)"
Write-Verbose "PSBoundparameters:"
write-verbose ($psboundparameters | out-string)

if (-Not $NextQuestion) {
    Write-Verbose "First question setup"
    #initialize some variables to keep track of correct answers
    $global:QuestionCount = 0
    $global:CorrectCount = 0
    $global:CommandCache = @()

    if ($ModuleName) {
        $Status = "Getting commands from module $modulename."
        Write-Verbose $Status
        Write-Progress -Activity $myinvocation.MyCommand -Status $status -CurrentOperation "Please wait..."
        $global:CommandCache = Get-command -CommandType Cmdlet,Function -Module $ModuleName   
        
    }
    else {
        $status = "Getting commands from all available modules."

        if ($exclude) {
            $status += " Excluding these modules: $($exclude -join ',') "
            #define a separate filter because this causes a problem in PowerShell v6 if $exclude is not specified
            $filter = {$_.Source -AND $_.source -notmatch $($exclude -join '|')}
        }
        else {
            $filter = {$_.Source}
        }
        Write-Verbose $status
        Write-Progress -Activity $myinvocation.MyCommand -Status $status -CurrentOperation "Please wait..."
        #get cmdlets and function that have a defined source which should be a module or snapin
        $global:CommandCache = (Get-command -CommandType Cmdlet,Function).Where($filter)
    }
    Write-Progress -Activity  $myinvocation.MyCommand -Completed
    Write-Verbose "Added $(($global:commandCache).count) commands to the command cache"
    if ((($global:commandCache).count) -eq 0) {
        Write-Warning "Failed to find commands in any matching modules."
        #bail out
        Return
    }
}
else {
    Write-Verbose "Continuing the quiz"
    Write-Verbose "Current question count: $($global:QuestionCount)"
    Write-Verbose "Current correct count: $($global:CorrectCount)"
    Write-Verbose "Current command cache: $(($global:commandCache).count)"
}

#select a random command with a legitimate synopsis
Write-Verbose "Selecting a random command"
do {
    $cmd = $global:CommandCache | Get-Random
    $synopsis = ($cmd | Get-Help).synopsis

} until ($synopsis -notmatch "(This cmdlet is not supported)|\[|(Fill in the Synopsis)" -AND $synopsis -match "\w{4,}")

#get other noun related commands
[object[]]$commands = @($cmd)
$commands += get-command -noun $cmd.noun | Where-Object {$_.name -ne $cmd.name} | Select-Object -first 4

#get additional random commands if there are not enough noun-related
if ($commands.count -lt 5) {
    Write-Verbose "Getting supplemental commands for answers"
    While ($commands.count -lt 5) {
        $add = Get-command -CommandType Cmdlet | Get-Random |
            Where-Object {$commands.name -notcontains $_.name}
        $commands += $add
    }
}
#randomize
$commands = $commands | get-random -count $commands.count

$Title = "PowerShell Pop Quiz"
$Cue = @"

Given this short cmdlet description: 

 $synopsis

 What command would you use?


"@

for ($i = 1; $i -lt $commands.count + 1; $i++) {

    $Cue += "  [$i]`t$($commands[$i-1].Name)`n"
}

Write-host $Title -ForegroundColor Cyan
Write-Host $Cue -ForegroundColor Yellow

Do {
    try {
        [validaterange(1, 5)][int32]$r = Read-Host -prompt "Select a menu choice [1-5]" -erroraction stop
        write-verbose "You entered $r"
    }
    Catch {
        #ignore the error
        write-warning $_.exception.message
        $r = 0
    }
} Until ($r -ge 1 -AND $r -le 5)

#increment the question counter
$global:QuestionCount++
if ($commands[$r - 1].name -eq $cmd.Name) {
    $global:CorrectCount++
    Write-Host "`nYou are Correct!!" -foregroundcolor green
}
else {
    Write-Host "`nThe correct answer is $($cmd.name)" -foregroundcolor Red
}

[string]$s = Read-Host "`nDo you want another question? Press any key to continue or Q to quit"
if ($s -match "^q") {
    $score = ($global:CorrectCount / $global:QuestionCount)
    $result = "Your scored {0} correct out of {1} [{2:p2}]" -f $global:CorrectCount, $global:QuestionCount, $score
    #colorize output based on score
    if ($score -ge .80) {
        $fg = "green"
    }
    elseif ($score -ge .40) {
        $fg = "yellow"
    }
    else {
        $fg = "red"
    }
    Write-Host $result -ForegroundColor $fg
    Remove-Variable CorrectCount, QuestionCount,CommandCache -Scope global
} 
else {
    if (-Not ($psboundParameters.containsKey("NextQuestion"))) {
            Write-Verbose "Flagging for next question"
            $psboundparameters.add("NextQuestion", $True)
        }
        Write-Verbose "Invoking quiz"
        #Write-verbose ($myinvocation.mycommand | out-string)
        &$($myinvocation.mycommand) @PSBoundParameters
        
    }

I hope you'll give it a shot and if you get errors, let me know. Also interested in any enhancements that would make this more useful. I have a few in mind already but I'd like to get some feedback on the core functionality.

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