/powershell

Pipelines, errors, and native exit codes

Pipelines

• PowerShell cmdlet pipelines pass objects. Parameters can accept pipeline input by value or by property name; use Get-Help and Get-Member to inspect the contract.
• A native process's stdin/stdout is a separate boundary from the PowerShell object pipeline. PowerShell 7.4 added byte-preserving behavior for native stdout redirection to files and byte data piped to native stdin; verify exact behavior on older runtimes and when combining stderr with stdout.

Errors and exit codes

• Non-terminating errors do not enter catch by default. Use -ErrorAction Stop when a cmdlet failure must be handled there.
• Native process status is reported through $LASTEXITCODE; capture or check it immediately after the relevant command and interpret it according to that program's contract. A nonzero code does not always mean failure, and stderr output alone does not establish failure.
• A native nonzero exit does not normally enter catch. $PSNativeCommandUseErrorActionPreference became stable in PowerShell 7.4 and can change this behavior when enabled.

Sources

• about_Pipelines
• about_Error_Handling