Find differences between two collections.
PowerShell: Compare-Object marks reference-only values with a left arrow and difference-only values with a right arrow.
$ErrorActionPreference = 'Stop'
Set-StrictMode -Version Latest
Compare-Object -ReferenceObject @('a','b') -DifferenceObject @('b','c') | Sort-Object InputObject | ForEach-Object { '{0}:{1}' -f $_.InputObject,$_.SideIndicator }Expected output EXAMPLE
a:<= c:=>
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. Compare-Object marks reference-only values with a left arrow and difference-only values with a right arrow.
Tested on Ubuntu 24.04.5 LTS · · 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
ebc9b8759b7c5856619034237472148b9c4ffb7588d90075ade8fe73180d6188- 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
a:<= c:=>
Exit code: 0. Standard error: empty. Validation: Exact stdout comparison. System-dependent values above are one recorded run.