# Add SharePoint PowerShell Snapin
if ( (Get-PSSnapin -Name Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue) -eq $null ) {
    Add-PSSnapin Microsoft.SharePoint.Powershell
}

$web = Get-SPWeb "http://url"
$listName = "List Name"
$list = $web.Lists[$listName]

$viewName = "View name"
$view = $list.Views[$viewName]
## Or get by view id
#$viewId = "A6932332-765A-4776-A1DF-18016DA1D645"
#$view = $list.GetView($viewId)

$query = New-Object Microsoft.SharePoint.SPQuery
$query.ViewAttributes = "Scope=""Recursive"""
$query.ViewXml = '<View><Query>' + $view.Query + '</Query></View>'

$items = $list.GetItems($query)
$items.Count

$web.Dispose()

using (SPSite siteColl = new SPSite("http://site_collection_URL"))
    {
        using (SPWeb site = siteColl.OpenWeb())
        {
            SPList list = site.Lists["list_name"];
            SPView view = list.Views["view_name"];
            SPQuery query = new SPQuery();
            query.ViewAttributes = "Scope="Recursive"";
            query.ViewXml = "<View><Query>" + view.Query + "</Query></View>";

            SPListItemCollection results = list.GetItems(query);
        }
    }