Ascii hex (IEEE754) 轉成 flaot in python

import sys
form binascii import unhexlify
s = unhexlify(sys.argv[1]) + unhexlify(sys.argv[2]) \
+ unhexlify(sys.argv[3]) + unhexlify(sys.argv[4])
import struct
result = struct.unpack_from('f', s)
print result[0]

Route setting under multi interfaces

The GATEWAY setting in ifcfg-eth0 will add a default gateway while interface starts, but may be overwrited by next started interface. To avoid this, remove the GATEWAY setting in ifcfg-eth0 and use route-eth0 file
Note. NetworkManager should be stopped

for Example, If there are two interface eth0 and eth1
ifcfg-eth0

DEVICE=eth0
IPADDR=10.3.23.221
NETMASK=255.0.0.0
#GATEWAY=10.3.23.254

ifcfg-eth1

DEVICE=eth0
IPADDR=172.18.101.2
NETMASK=255.255.0.0
#GATEWAY=172.18.254.254

route-eth0

default 10.3.23.254 dev eth0

route-eth1

172.16.0.0/12 via 172.18.254.254 dev eth1

Create a Package repo

1. create /var/pxe/centos6 directory

mkdir -p /var/pxe/centos6

2. mount iso and copy all files into /var/pxe/centos6 and create repo

cp -ivr /media/CentOS_6.3_Final/* /var/pxe/centos6
cd /var/pxe/centos6
createrepo .

3. create conf file /etc/httpd/conf.d/pxeboot.conf

Alias /centos6 /var/pxe/centos6
<Directory /var/pxe/centos6>
  Options Indexes FollowSymLinks
  AllowOverride None
</Directory>

4. Allow selinux httpd_sys_content_t

cd /var/pxe
chcon -R -t httpd_sys_content_t './centos6'

5. Restart httpd

service httpd restart

6. Open browser to check "http://127.0.0.1/centos6" is available Reference:
http://practical-tech.blogspot.tw/2011/10/how-to-configure-pxe-server-in-rhel-6.html
http://httpd.apache.org/docs/current/sections.html

Install RockMongo on Ubuntu

1. Install mongodb
follow the link below to install mongodb
http://docs.mongodb.org/manual/tutorial/install-mongodb-on-ubuntu/


2. Install php5, php-pear
>apt-get install php5 php-pear

3. Install php-mongo
http://www.php.net/manual/en/mongo.installation.php

4. download rockmongo and the unzip and put in /var/www
http://rockmongo.com/downloads

5. restart apache2 mongodb
>service apache2 restart
>service mongodb restart
(If mongodb is locked, please check below link)
http://blog.brianbuikema.com/2011/01/mongodb-ubunto-overview-installation-setup-dev-python-2/


6. Login with admin/admin on http://localhost/rockmongo
(Modify config.php to change login username/password) 

Disable ping response in Linux

sysctl -w net.ipv4.icmp_echo_ignore_all=1

http://www.linuxarticles.org/2010/10/disable-ping-response-in-linux/

Install mongodb on Ubuntu

1. import public key

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv 7F0CEB10

2. create /etc/apt/sources.list.d/10gen.list

deb http://downloads-distro.mongodb.org/repo/ubuntu-upstart dist 10gen

3.

sudo apt-get update

4.

sudo apt-get install mongodb-10gen

Reference: http://docs.mongodb.org/manual/tutorial/install-mongodb-on-debian-or-ubuntu-linux/

tsocks

1. install epel first
http://fedoraproject.org/wiki/EPEL
1. insatll tsocks

yum install tsocks

2. add file /etc/tsocks.conf

server = 127.0.0.1
server_type = 5
server_port = 1234

3. establish ssh tunnel

ssh -D 1234 user@xxx.remote.host

4. wget with socks proxy

tsocks wget http://get.something

5. you might want to unset the http_proxy variable

unset http_proxy