One of the page layout templates was changed in a SharePoint 2010 site collection that I was working on.  There were already over 300 pages that were creating using the old Page Layout.  Enter… Powershell!  It took about two hours to write this script (with help from The Google) but it will probably save a day of work updating all those pages individually through the UI.

The script takes three parameters, the old or current page layout name, the new page layout name and an optional –all parameter which will traverse all the sites of a site collection.  Enjoy.

# Description:
# Update the layout page for all matching pages of the current page layout
# Checkout, Change layout, Check-in pages in a site collection
#
# Syntax:
# ./UpdateLayoutPages [-PageLayoutCurrent] [-PageLayoutNew] [-all]
#
# Parameters:
# -PageLayoutCurrent     - The page layout that is currently in use and will be updated
# -PageLayoutNew        - The new page layout that pages will be updated to
# -all                     - Update subsites in the site collection
#
# Modifications:
# v1.0 - April 5th, 2011
# Initial version
#
# Settings
set-variable -option constant -name url  -value http://localhost   # Site collection
set-variable -option constant -name comment -value "Batch PageLayout Update"   # Publishing comment

# Function: Update-SPPagesPageLayout
# Description: Update a single page in a Publishing Web
# Parameters: publishingPage, pageLayout, comment
function Update-SPPagesPageLayout ([Microsoft.SharePoint.Publishing.PublishingPage]$publishingPage,
    [Microsoft.SharePoint.Publishing.PageLayout] $pageLayoutNew, [string]$comment)
{
    Write-Host "Updating the page:" $publishingPage.Name "to Page Layout:" $pageLayoutNew.Title
    $publishingPage.CheckOut();
    $publishingPage.Layout = $pageLayoutNew;
    $publishingPage.ListItem.Update();
    $publishingPage.Update()
    $publishingPage.CheckIn($comment);
    if ($publishingPage.ListItem.ParentList.EnableModeration)
    {
        $publishingPage.ListItem.File.Approve("Publishing Page Layout correction");
    }
}

# Function: Update-AllSPPagesPageLayouts
# Description: Loop through all the pages in a Publishing Web and update their page layout
# Parameters: web, pageLayoutCurrent, pageLayoutNew, comment
# comment Comment to accompany the checkin
Function Update-AllSPPagesPageLayouts ([Microsoft.SharePoint.SPWeb]$web, [Microsoft.SharePoint.Publishing.PageLayout]$pageLayoutCurrent,
    [Microsoft.SharePoint.Publishing.PageLayout]$pageLayoutNew, [string]$comment)
{
    #Check if this is a publishing web
    if ([Microsoft.SharePoint.Publishing.PublishingWeb]::IsPublishingWeb($web) -eq $true)
    {
      $pubweb = [Microsoft.SharePoint.Publishing.PublishingWeb]::GetPublishingWeb($web);
      $pubcollection=$pubweb.GetPublishingPages()
      #Go through all pages checking for pages with the "current" page layout
      for($i=0; $i -lt $pubcollection.count; $i++)
      {
        if($pubcollection[$i].Layout.Title -eq $pageLayoutCurrent.Title)
        {
            Update-SPPagesPageLayout $pubcollection[$i] $pageLayoutNew $comment
        }
      }
    }
    $web.Close();
}

# Check Parameters
if(($args[0] -ne $null) -and ($args[1] -ne $null))
{
    Write-Host "** Update Layout Pages from-" $args[0] "-to-" $args[1] "-on URL" $url
    $pageLayoutNameCurrent = $args[0];
    $pageLayoutNameNew = $args[1];

    $site = new-object Microsoft.SharePoint.Publishing.PublishingSite($url)

    Write-Host "Checking if both page layouts exist in the site..."
    # Check if the current pagelayout exists in this site collection
    $pageLayouts = $site.GetPageLayouts($true);

    $pageLayouts | ForEach-Object {
        if ($_.Title -eq $pageLayoutNameCurrent)
        {
            Write-Host "Found CURRENT page layout: " $pageLayoutNameCurrent
            $pageLayoutCurrent = $_;
        }
    }

    # Check if the new pagelayout exists in this site collection
    $pageLayouts | ForEach-Object {
        if ($_.Title -eq $pageLayoutNameNew)
        {
            Write-Host "Found NEW page layout: " $pageLayoutNameNew
            $pageLayoutNew = $_;
        }
    }      

    # Do not continue if the either pageLayout does not exist
    if(($pageLayoutCurrent -ne $null) -and ($pageLayoutNew -ne $null))
    {
        # Update all subsites
        if($args[2] -eq "-all")
        {
         $site.Site.allwebs | foreach {
            Write-Host "Checking Web: " $_.Title
            Update-AllSPPagesPageLayouts $_ $pageLayoutCurrent $pageLayoutNew $comment
            }
        }
        else
        {
         $site.rootweb | foreach {
            Write-Host "Checking Web: " $_.Title
            Update-AllSPPagesPageLayouts $_ $pageLayoutCurrent $pageLayoutNew $comment
            }
        }
    }
    Write-Host "**Done"
}
else
{
    Write-Host "Missing arguments.  Please check your parameters"
}
#End