--------------------------------------------------------------------
scanning all network devices using arp-scan on 192.168.254.0 network:
arp-scan --interface=eth1 192.168.254.0/24
--------------------------------------------------------------------

iptables -t nat -A PREROUTING -p tcp -i eth0 -d 192.168.2.109 --dport 10001 -j DNAT --to 192.168.1.32:10000


iptables -A INPUT -i eth0 -s 192.168.254.2 -j DROP


iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE


iptables-t nat-A PREROUTING -i eth0 -p TCP --dport4662 -j DNAT --to
192.168.0.10:4662
iptables-t nat-A PREROUTING -i eth0 -p UDP --dport4672 -j DNAT --to
192.168.0.10:4672


-------------
proxy port forwarding linux.
ssh -f -L 8080:localhost:8080 leming@ehion.com sleep 9999
-------------

-------------------------
Limit traffic on the interface down to 220kbit/s
tc qdisc add dev eth0 root tbf rate 220kbit latency 50ms burst 1540
-------------------------

------------------------------------
fixing table in mysql after crash:

DEBUG MODE

SQL Error : 145 Table './c64forum/phpbb_config' is marked as crashed and
should be repaired

mysqlcheck --auto-repair c64forum phpbb_config

c64forum.phpbb_config
warning  : Table is marked as crashed
warning  : 2 clients are using or haven't closed the table properly
status   : OK
-------------------------------------

-----------------------------------------------------
Quick backup (dump) of mysql database:

mysqldump -u user -p nameofdatabase > ch01032010.sql
-----------------------------------------------------

-------------------
piping ls to xargs:
ls -la|grep 2010-03-03|awk '{print $8}'|xargs -i -t mv {} /home/leming/perl/tmp/03032010/
-------------------

cat access_log|egrep -o [0-9]+\\.[0-9]+\\.[0-9]+\\.[0-9]+|uniq| while read q; do echo -n "IP:$q,";host $q|awk -F'pointer ' '{print "hostname="$2}'; done