unix backup with tar and mt

Rewind tape drive:# mt -f /dev/st0 rewind
Backup directory /www and /home with tar command (z - compressed):
# tar -czf /dev/st0 /www /home
Find out what block you are at with mt command:
# mt -f /dev/st0 tell
Display list of files on tape drive:
# tar -tzf /dev/st0
Restore /www directory:
# cd /
# mt -f /dev/st0 rewind
# tar -xzf /dev/st0 www
Unload the tape:
# mt -f /dev/st0 offline
Display status information about the tape unit:
# mt -f /dev/st0 status
Erase the tape:
# mt -f /dev/st0 erase
You can go BACKWARD or FORWARD on tape with mt command itself:
(a) Go to end of data:
# mt -f /dev/nst0 eod
(b) Goto previous record:
# mt -f /dev/nst0 bsfm 1
(c) Forward record:
# mt -f /dev/nst0 fsf 1

deleting message from postfix queue

To list the queue execute:
mailq
You can find the problematic messages id and the execute:

find /var/spool/postfix -name "messegeID" | xargs rm