Gets an object of type System.IO.FileInfo and returns the object with generated filename based on the old name and timestamp. May be useful for creating backups, rotating logs etc.

Get-TimeStampedFileName.ps1

function Get-TimeStampedFileName {
    [CmdletBinding()]
    [OutputType([System.IO.FileInfo])]
    param   (
        [Parameter(Mandatory,ValueFromPipeline,ValueFromPipelineByPropertyName,Position=0)]
        [Alias('FullName', 'p')]
        [System.IO.FileInfo]$Path,

        [Parameter(Position=1)]
        [Alias('u', 'z')]
        [switch]$UTC
    )
    begin   {
        [string]$patternTimeStamp   =   '{0:yyyy-MM-dd_HH-mm-ss}_{1}'
    }
    process {
        if  ($UTC)  {
            [datetime]$objTimeStamp =   [datetime]::UtcNow
        }
        else {
            [datetime]$objTimeStamp =   [datetime]::Now
        }
        [string]$fileNameNew    =   [string]::Format(
            $patternTimeStamp,
            $objTimeStamp,
            $Path.Name
        )
        [string]$outputPathNew  =   [System.IO.Path]::Combine(
            $Path.DirectoryName,
            $fileNameNew
        )
        return  [System.IO.FileInfo]::new($outputPathNew)
    }
    end     {}
}