Resolution

Add-PSSnapin Microsoft.SharePoint.PowerShell

function CheckInDocument([string]$url){

    $spWeb=Get-SPWeb $url

    $spDocument=$spWeb.Lists.TryGetList("Documents");

    Write-Host "需要签入文件的文档库:$($spDocument.Title)"

    $files=$spDocument.CheckedOutFiles

    Write-Host "需要签入的文件个数:$($files.Count)"

    $files|where{$_.CheckOutStatus -ne "None"}|%{

      $_.TakeOverCheckOut();
$docItem=$spDocument.GetItemById( $_.ListItemId);
$docItem.File.CheckIn("Administrator Check In");
Write-Host "$($docItem.File.Name) Check In" -ForegroundColor Green
}
$spWeb.Dispose(); } CheckInDocument("http://reus");
05-02 01:33