The optional -sort sorts the list according to the messages' timestamps, oldest messages first. This may take a while if the mail queue is very large.

The optional -batch uses an alternative, machine-parsable output format, one line per message:

size;qid;date;user;from;[status;recipient];[status;recipient];[...]

Only the superuser can view the contents of the entire mail queue. Everyone else can only see their own messages.