Since I'm wasting my summer inside anyways I might aswell do something helpful, and write the script for you. Assuming you're using Windows, the following PowerShell script would fit your scenario (just save as a .ps1 file and modify the path at the top).
$TVShowFolderPath = "X:\Series\Dexter";
$TVShowSeasons=$(get-childitem "$TVShowFolderPath");
foreach( $s in $TVShowSeasons)
{
if( ($s.PSisContainer) -and ($s -imatch "^(Season )(\d{2}|\d{1})$") )
{
$season = $matches[2];
write-host "Season $season";
$episodes=$(get-childitem $s.FullName);
foreach( $ep in $episodes)
{
if( $ep -imatch "^(season) (\d{2}|\d{1}) (ep) (\d{2}|\d{1})(.*)$")
{
$newName = "$($season)x$($matches[4])$($matches[5])";
write-host "`tEpisode: `"$($ep.Name)`" --> `"$newName`"";
Rename-Item $ep.FullName $newName;
}
}
}
}
If you want to see if it spits out the correct names first just comment out the line starting with "Rename-Item".