###Edit source.list
ensure the universe components is enabled.
martin@PC:~/git/blog/_posts$ cat /etc/apt/sources.list
deb http://ubuntu.cn99.com/ubuntu/ quantal main
deb-src http://ubuntu.cn99.com/ubuntu/ quantal main
deb http://ubuntu.cn99.com/ubuntu/ quantal universe
deb-src http://ubuntu.cn99.com/ubuntu/ quantal universe
###update apt
martin@PC:~/git/blog/_posts$ sudo apt-get update
###install
martin@PC:~/git/blog/_posts$ sudo apt-get install python-html2text^C
html2markdown ready
martin@PC:~/git/blog/_posts$ html2markdown –version
html2markdown 3.200.3