1. To see the mail queue:
mailq
2. To flush the mail queue:
postfix flush
or
postfix -f
3. To remove all mails from the queue:
postsuper -d ALL
4. To remove all mails in the deferred queue:
postsuper -d ALL deferred
5. To delete all queued messages from or to the domain called webserverpage.com:
./postfix-delete.pl webserverpage.com
Note: You may download the script on the link below.
http://blog.webserverpage.com/?p=541
6. To delete all queued messages that contain the word “virus” in the email.
./postfix-delete.pl virus
7. To know the number of messages sitting in the deferred queue:
find /var/spool/postfix/deferred -type f | wc -l
8. Sort user email accounts with corresponding number(s) of email.
mailq|grep ^[A-F0-9]|cut -c 42-80|sort |uniq -c|sort -n|tail