SharePoint 2013: Delete a custom permissions using PowerShell

$spSite = Get-SPSite "http://sedwdevrtm:432/sites/com"[xml]$file = Get-Content "C:\Users\Administrator\Desktop\XML\XmlSitePermissions.xml"$Permissionname = $file.sites.site.sitepermission $spWeb = $spSite | Get-SPWeb  # we add a new Permission Level name "DotcomReadonly" to the site, which will allow users to only add new items (no editing or removing) # check to see if the permission your are going to add is already existing.. if null proceedforeach ($Permission in $Permissionname){Write-Host ($Permission)     if($spWeb.RoleDefinitions[$Permission] -ne $null)        {                     write-Host ($spWeb.RoleDefinitions.Name[$Permission]) -BackgroundColor DarkGreen                    $spRoleDefinition = New-Object Microsoft.SharePoint.SPRoleDefinition                        $spRoleDefinition.Name = $Permission                       $spWeb.RoleDefinitions.Delete($spRoleDefinition.Name)                     Write-Host $spRoleDefinition.Name " Deleted successfully" -BackgroundColor Gray             }        else        {        Write-Host "Custom Permission doesn't exist"        }}$spWeb.Dispose()$spSite.Dispose()

Previous article xml can be used to delete or use for loop to compare and delete the permissions:

      <    sites    >  
      <    site    >  
      <    sitepermission    >DotcomReadonly</    sitepermission    >  
      <    sitepermission    >DotcomContribute</    sitepermission    >  
      <    sitepermission    >DotcomSiteAdministrator</    sitepermission    >  
      </    site    >  
                    <      Permission      >      
                        <      Permissions      >ViewListItems,AddListItems,Open,ViewPages</      Permissions      >      
                        <      Permissions      >ViewListItems,AddListItems,OpenItems,Open,ViewPages</      Permissions      >      
                        <      Permissions      >ManageLists</      Permissions      >      
                    </      Permission      >      
      </    sites    >