Type: boolean
Default: unset
Used in connection with the pipe-message command and the ``tag-prefix'' operator. If this variable is unset, when piping a list of tagged messages Mutt will concatenate the messages and will pipe them as a single folder. When set, Mutt will pipe the messages one by one. In both cases the the messages are piped in the current sorted order, and the $pipe_sep separator is added after each message.