private def csearch(request: SearchRequest): IO[Either[ErrType, List[String]]] = IO {
    val indexDir = cindexDir.indexDirAs[String]
    val env      = ("CSEARCHINDEX", indexDir)
    val log      = ProcessLogger((o: String) => _.asRight, (e: String) => ErrType(_).asLeft)
    logger.debug(s"running CSEARCHINDEX=$indexDir ${arguments(request).mkString(" ")}")
    for {
      processResults <- IO((Process(arguments(request), None, env) #| Seq("head", "-1001")).lineStream_!(log).toList)
      (errors, success) = processResults.partition(_.isLeft)
    } yield if (errors.size > 0)
             errors.map(_.left.get).head
            else
             success.map(_.right.get)
  }.flatten