View the source for a command

Get-CommandSource.ps1

function Get-CommandSource {
    param (
        [Parameter(Mandatory)]
        [String]$Name
    )

    try {
        $commandInfo = Get-Command $Name
        if ($commandInfo -is [System.Management.Automation.AliasInfo]) {
            $commandInfo = $commandInfo.ResolvedCommand
        }

        if ($commandInfo -is [System.Management.Automation.CmdletInfo]) {
            $assembly = $commandInfo.ImplementingType.Assembly.Location
            $type = $commandInfo.ImplementingType.FullName
            if (Get-Command dnspy -ErrorAction SilentlyContinue) {
                dnspy $assembly --select T:$type
            } elseif (Get-Command ilspy -ErrorAction SilentlyContinue) {
                ilspy $assembly /navigateTo:T:$type
            } else {
                throw 'No decompiler present'
            }
        } else {
            $commandInfo.Definition
        }
    } catch {
        $pscmdlet.ThrowTerminatingError($_)
    }
}