how to save a list of installed packages and install these packages later

The following solution may be worth trying:

http://www.arsgeek.com/2006/09/19/ubuntu-tricks-how-to-generate-a-list-of-installed-packages-and-use-it-to-reinstall-packages/

Loosing keyboard when using CTRL-s in a terminal

In a linux terminal, if it seems that you loose the keyboard control when pressing CTRL-s (ex. when saving in Emacs by C-x C-s), you may use a telnet connection to a server (may be through qlogin). In this case, C-s stops the terminal output and C-q starts it back. To fix it, you can run the following command before the connection or add it to ~/.bashrc:

stty -ixon

Sources:

• http://gridengine.org/pipermail/users/2011-February/000154.htm
• http://publib.boulder.ibm.com/infocenter/aix/v6r1/index.jsp?topic=%2Fcom.ibm.aix.cmds%2Fdoc%2Faixcmds5%2Fstty.htm

Alternatively you MAY try the following: add the line below to ~/.screenrc and restart Emacs:

defflow off

(source http://superuser.com/questions/251446/problem-with-gnu-screen-when-using-emacs-c-x-c-s-save-buffer)