Dear Maintainer, I want to delete all messages received before a date. I allready use this command with redhat to purge mailboxes : echo "d (before 11-Jun-2015)" | mailx It does not seems to work with debian and the command returns "Non-numeric second argument" Is the date format different in debian ? (before date) All messages that were received before date; date must be in the form d[d]-mon-yyyy, where d[d] is the day of the month as one or two digits, mon is the name of the month (one of 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', or 'Dec'), and yyyy is the year as four digits; e.g. "30-Aug-2004".