Formatting and Output

PowerShell decides automatically how to display objects — as a table for a few properties, as a list for many. The Format-* cmdlets let you choose.

$user = [pscustomobject]@{ Name = 'Ada'; City = 'London'; Age = 36 }

$user | Format-Table
$user | Format-List

Name City   Age
---- ----   ---
Ada  London  36


Name : Ada
City : London
Age  : 36

• Format-Table — columns; -AutoSize fits them to the content.
• Format-List — one property per line, ideal for objects with many properties. Format-List * shows every property, including ones hidden by default.

Format last, and only for display

Format-* cmdlets turn objects into formatting instructions. After formatting, the data is gone:

$formatted = [pscustomobject]@{ Name = 'Ada' } | Format-Table
$formatted[0].GetType().Name

FormatStartData

So Get-Process | Format-Table | Export-Csv produces a useless CSV of formatting objects. Always put Format-* at the end of a pipeline, and never in the middle of data processing.

Sending output elsewhere

Write-Output vs Write-Host

function Get-Answer {
  Write-Host "Calculating..."
  Write-Output 42
}

$result = Get-Answer
"The result is $result"

Calculating...
The result is 42

• Write-Output (or simply leaving a value on its own line) sends data down the pipeline — it's what a function returns.
• Write-Host writes directly to the screen and is not captured in $result. Use it only for display messages, never for data.