HowTo: Debug a Shell Script Under Linux or UNIX

http://www.cyberciti.biz/tips/debugging-shell-script.html

scp examples

http://www.hypexr.org/linux_scp_help.php

use -r to copy a directory.

Global variable in python

http://docs.python.org/faq/programming.html#what-are-the-rules-for-local-and-global-variables-in-python

http://stackoverflow.com/questions/423379/using-global-variables-in-a-function-other-than-the-one-that-created-them

In short, when modify the global variable in a function, need to explicitly define "global g_sth". This is to avoid using global variables.

Python tutorial and start up script

tutorial:

http://docs.python.org/tutorial/index.html

http://net.tutsplus.com/tutorials/python-tutorials/python-from-scratch-object-oriented-programming/

xml:
http://www.learningpython.com/2008/05/07/elegant-xml-parsing-using-the-elementtree-module/

start up script:

http://stackoverflow.com/questions/5359306/set-and-require-default-python-script-optionparser

from optparse import OptionParser
import sys
def main():
   usage = "usage: %prog [options] arg"
   parser = OptionParser(usage)
   parser.add_option('-d', '--directory',
           action='store', dest='directory',
           default=None, help='specify directory')
   parser.add_option('-f', '--file',
           action='store', dest='filename',
           default=None, help='specify file')
   parser.add_option('-v', '--version',
                     action="store_true", dest="show_version",
                     default=False, help='displays the version number')
   if len(sys.argv) == 1:
       parser.print_help()
       sys.exit()
   (options, args) = parser.parse_args()
   # rest of program...
if __name__ == '__main__':
   main()

QEMU : change cdrom

http://en.wikibooks.org/wiki/QEMU/Monitor#change

(qemu) info block
ide0-hd0: type=hd removable=0 file=/path/to/winxp.img
ide0-hd1: type=hd removable=0 file=/path/to/pagefile.raw
ide1-hd1: type=hd removable=0 file=/path/to/testing_data.img
ide1-cd0: type=cdrom removable=1 locked=0 file=/dev/sr0 ro=1 drv=host_device
floppy0: type=floppy removable=1 locked=0 [not inserted]
sd0: type=floppy removable=1 locked=0 [not inserted]
(qemu) change ide1-cd0 /path/to/my.iso
(qemu) change ide1-cd0 /dev/sr0 host_device 

Ubuntu network restart

sudo /etc/init.d/networking restart

pxe boot on KVM

Fedora:

http://forums.fedoraforum.org/archive/index.php/t-198552.html

Debin:

http://box.matto.nl/kvmpxe.html

Ubuntu Lucid:

http://mrpointy.wordpress.com/2010/05/03/pxe-boot-kvm-guests/