0xF0Lesson 16 of 17

The best of PowerShell 7

Write modern PowerShell with ternaries, null operators, pipeline chains, -Parallel and friendlier errors.

22 min 7-question quiz

By the end of this lesson you can

Use the ternary, null-coalescing and null-conditional operators
Chain commands with && and ||, and run work in parallel with ForEach-Object -Parallel
Use PowerShell 7 conveniences: Get-Error, -AsArray, Join-String, $IsWindows and more

PowerShell 7 added a run of small features that make scripts shorter and clearer. This lesson’s examples are not runnable in the browser - the runner here is PowerShell 6.2 - so open pwsh on your own machine and try each one. (Every output shown was checked against PowerShell 7.)

Feature	Example	Since
Ternary operator	`$big ? 'barn' : 'cottage'`	7.0
Null-coalescing	`$nickname ?? 'no nickname'`	7.0
Null-coalescing assignment	`$config ??= @{}`	7.0
Null-conditional member access	`${dragon}?.Name`	7.1
Pipeline chain operators	`Test-Path $f && Remove-Item $f`	7.0
`ForEach-Object -Parallel`	`1..10 \| ForEach-Object -Parallel { ... }`	7.0
`Get-Error`	a detailed view of the last error	7.0
`ConvertTo-Json -AsArray`	always produce a JSON array	7.0
`$PSStyle`	colors and formatting in the console	7.2

Ternaries and null operators

operators.ps1

1$wingspan = 12
2$wingspan -ge 10 ? 'needs the big barn' : 'fits the cottage'
3$nickname = $null
4$nickname ?? 'no nickname'
5$settings = $null
6$settings ??= @{ Theme = 'ember' }
7$settings.Theme
8$dragon = $null
9"[$(${dragon}?.Name)]"
10$dragon = [pscustomobject]@{ Name = 'Skyla' }
11${dragon}?.Name

Output

needs the big barn
no nickname
ember
[]
Skyla

condition ? a : b replaces a four-line if/else when you just need a value.
$x ?? default gives $x unless it’s $null. Unlike if ($x), an empty string or 0 still counts as a value.
$x ??= value assigns only when $x is $null - lazy initialization in one line.
${x}?.Property gives $null instead of an error when $x is $null (and the braces are required, because ? is a legal character in variable names).

Pipeline chains: && and ||

a && b runs b only if a succeeded; a || b runs b only if a failed. Success means $? was true - for native programs, an exit code of 0. They make build-and-deploy one-liners read like Bash:

chains.ps1

Write-Output 'fed Ember' && Write-Output 'then fed Glim'
Get-Item 'no-such-dragon.txt' 2>$null || Write-Output 'no file, so fall back'
Get-Item 'no-such-dragon.txt' 2>$null && Write-Output 'never printed'

Output

fed Ember
then fed Glim
no file, so fall back

Parallel processing

ForEach-Object -Parallel runs the script block for several items at the same time in separate threads. Results arrive in whatever order they finish, so sort them if order matters. Outside variables need $using:.

parallel.ps1

1$multiplier = 7
2$readings = 'volcano', 'lagoon', 'tower' | ForEach-Object -Parallel {
3  Start-Sleep -Milliseconds 200
4  '{0}: {1}' -f $_, ($_.Length * $using:multiplier)
5} -ThrottleLimit 3
6$readings | Sort-Object

Output

lagoon: 42
tower: 35
volcano: 49

Smaller conveniences

conveniences.ps1

1'Ember', 'Glim', 'Skyla' | Join-String -Separator ', ' -OutputPrefix 'Dragons: '
2[pscustomobject]@{ Name = 'Glim' } | ConvertTo-Json -AsArray -Compress
3$parsed = '{"name":"Vesper","meals":3}' | ConvertFrom-Json -AsHashtable
4$parsed['meals'] + 1
5$IsWindows -or $IsLinux -or $IsMacOS
6'{"name":"Pebble"}' | Test-Json

Output

Dragons: Ember, Glim, Skyla
[{"Name":"Glim"}]
4
True
True

Key takeaways

Ternary ? :, ??, ??= and ${x}?.Prop shorten everyday checks (7.0+, ?. 7.1+).
&& and || chain commands on success or failure, Bash-style.
ForEach-Object -Parallel runs work concurrently; use $using: and sort the results.
Join-String, -AsArray, -AsHashtable, Test-Json, Get-Error and $IsWindows are small but handy - and #Requires -Version 7 documents the dependency.

Lesson quiz

7 questions · pass with 5 correct · up to 50 XP

Passing this quiz completes the lesson and keeps your streak going. Questions you miss come back in review sessions later.

Questions about this lesson

Stuck? Ask. Figured something out? Share it. Explaining is one of the best ways to learn.

Loading posts…