Spying on Function Source Code

Here is a quick way how to find the source code of PowerShell functions:

${function:Clear-Host} | clip

This would copy the Clear-Host source code to the clipboard, and when you paste it, you’ll see how Clear-Host works:

$RawUI = $Host.UI.RawUI
$RawUI.CursorPosition = @{X=0=0}
$RawUI.SetBufferContents(
    @{Top = -1 Bottom = -1 Right = -1 Left = -1},
    @{Character = ' ' ForegroundColor = $rawui.ForegroundColor BackgroundColor = $rawui.BackgroundColor})

As always, there is much to learn. If you’d like to fill the PowerShell console with a character different than space, i.e. ‘X’, with yellow foreground on green background, try this:

$host.UI.RawUI.SetBufferContents(
    @{Top = -1 Bottom = -1 Right = -1 Left = -1},
    @{Character = 'X' ForegroundColor = 'Yellow' BackgroundColor = 'Green'})

Note that this works only in true PowerShell console hosts.

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