Error Handling

PowerShell · Reference cheat sheet

📋 Overview

PowerShell has terminating and non-terminating errors. Use -ErrorAction, try/catch/finally, and $Error to control behavior. Prefer terminating errors for scripts that must stop; use -ErrorVariable to capture without stopping.

🔧 Core concepts

catch [System.IO.IOException] filters by type. $PSItem / $_ in catch is the error record.

💡 Examples

Try/catch:

try {
  Get-Content -LiteralPath .\missing.txt -ErrorAction Stop
} catch {
  Write-Error "Failed: $($_.Exception.Message)"
} finally {
  'cleanup'
}

Capture without stop:

Get-ChildItem .\nope -ErrorAction SilentlyContinue -ErrorVariable e
if ($e) { $e | ForEach-Object Message }

Native commands:

git rev-parse HEAD
if ($LASTEXITCODE -ne 0) { throw "git failed: $LASTEXITCODE" }

Preference scope:

$ErrorActionPreference = 'Stop'

⚠️ Pitfalls

• Default -ErrorAction Continue means scripts keep going after many failures.
• try/catch only catches terminating errors—add -ErrorAction Stop to cmdlets.
• Swallowing errors with SilentlyContinue hides root causes.
• $Error[0] is the newest; clear carefully ($Error.Clear()).
• Mixing throw strings vs ErrorRecord changes catch behavior slightly.
• Pipeline errors may not abort the whole pipeline unless preference is Stop.

🔗 Related

• cmdlets.md
• scripting.md
• functions.md
• jobs.md
• conditionals.md