In this article I am going to demonstrates How to Export SharePoint custom list schema to CSV file. This example applies to SharePoint 2010 and SharePoint 2013 environment.

[system.reflection.assembly]::loadwithpartialname("microsoft.sharepoint")
$listName="DemoList";
$siteURL="http://localhost/";
$csvPath="C:PowerOutput"+ $listName + ".csv";
$oSite= New-Object Microsoft.SharePoint.SPSite($siteURL)
$oWeb=$oSite.OpenWeb()
$oList=$oWeb.Lists[$listName]
#Get only custom fields which are created by user
$oList.Fields | ?{$_.CanBeDeleted -eq $true -and $_.Hidden -eq $false} | select Title,Internalname,Type |Sort-Object title| Export-Csv -Path $csvPath -Encoding ascii -NoTypeInformation
$oWeb.Dispose()
$oSite.Dispose()