To complement zett42's helpful answer:
If you're running PowerShell (Core) 7+, you can pass the file path that represents the terminal (console) to the (positionally implied) -FilePath parameter (in Windows PowerShell, this causes an error, unfortunately - see bottom section):
# PowerShell 7+ only # Windows Get-Content data.txt | Tee-Object CON | data_processor.exe # Unix-like platforms (Linux, macOS) Get-Content data.txt | Tee-Object /dev/tty | data_processor.exe # Platform-agnostic Get-Content data.txt | Tee-Object ($IsWindows ? 'CON': '/dev/tty') | data_processor.exe
This passes all data through while also printing it topasses all data through while also printing it to the terminal (console), richly formatted, as usual, as it becomes available - unlike with the terminalTee-Object -Variable approach, which requires collecting all output in memory first (consolewhich is a concern both in terms of output timing and memory consumption), richly formatted, as usual.
Windows PowerShell solution: Custom proxy (wrapper) function Tee-Host wraps Out-Host while also passing its input through; use it instead of Tee-Object:
function Tee-Host { [CmdletBinding()] param( [Parameter(ValueFromPipeline)] $InputObject ) begin { $scriptCmd = { Out-Host } $steppablePipeline = $scriptCmd.GetSteppablePipeline($myInvocation.CommandOrigin) $steppablePipeline.Begin($PSCmdlet) } process { # Pass to Out-Host, and therefore to the host (terminal) $steppablePipeline.Process($InputObject) # Pass through (to the success stream) $InputObject } end { $steppablePipeline.End() } }
In effect, Tee-Host behaves like Tee-Object CON / Tee-Object /dev/tty in PowerShell 7+, where Tee-Host works too.
Even in PowerShell 7+ Tee-Host may be preferable, because it uses colored output unconditionally, whereas the coloring behavior of Tee-Object CON / Tee-Object /dev/tty depends on the value of $PSStyle.OutputRendering
It is the use of a proxy function with a steppable pipeline wrapping Out-Host that ensures that the to-host formatted output looks the same as when the input is directly sent to the host.
