Restore an environment value after temporary use.

PowerShell: Use finally so temporary process configuration does not leak to subsequent work; remove the entry when it was originally absent.

$ErrorActionPreference = 'Stop'
Set-StrictMode -Version Latest
$previous = [Environment]::GetEnvironmentVariable('SNIPPET_MODE')
try {
    $env:SNIPPET_MODE='temporary'
    $env:SNIPPET_MODE
} finally {
    if ($null -eq $previous) { Remove-Item -LiteralPath 'Env:SNIPPET_MODE' -ErrorAction SilentlyContinue }
    else { [Environment]::SetEnvironmentVariable('SNIPPET_MODE',$previous) }
}
[Environment]::GetEnvironmentVariable('SNIPPET_MODE') -eq $previous

Expected output EXAMPLE

temporary
True

Details

Requires PowerShell 7. Save as snippet.ps1 and run pwsh -NoProfile -File snippet.ps1. Tested on Linux; these examples use portable paths and cmdlets. Use finally so temporary process configuration does not leak to subsequent work; remove the entry when it was originally absent.

✓ Verified

Tested on Ubuntu 24.04.5 LTS · 2026-11-02 18:23:32 UTC · PowerShell 7.6.6 · powershell 7.6.6-1.deb

Test inputs, results and environment

The exact published code ran in a dedicated Linux test container with prepared inputs. Snippet process uid 65534 with a read-only root filesystem and temporary working files. Networking disabled. Fixtures and output records are isolated from the application database. Testing covers this example and its stated checks, not every input, operating system, or runtime version. The Linux container shares its host's kernel; this is not a native Windows test.

Architecture / host kernel: x86_64 / 6.18.54.1-microsoft-standard-WSL2
Snippet identity / locale: uid=65534, gid=65534 (unprivileged process) / C.UTF-8
Interpreter invocation: pwsh -NoLogo -NoProfile -NonInteractive -File snippet.ps1
Container image ID: sha256:ec91410a8f6ec3e985830b5e3a0560306d36f8c1c5ccd91a6699abe707123fa3
Code SHA-256: fb64f6393c197b343cc9c1c59738728d2e502f1e2bdabab083e0fed2dddb0576
Dependencies: powershell 7.6.6-1.deb

Test input setup

These are the prepared inputs used by the test harness. See Details above for the prerequisites and how to run this example.

# No input files required.

Observed standard output

temporary
True

Exit code: 0. Standard error: empty. Validation: Exact stdout comparison. System-dependent values above are one recorded run.