When I tried to install skype according to
http://www.if-not-true-then-false.com/2012/install-skype-on-fedora-centos-red-hat-rhel-scientific-linux-sl/
there is a conflict on tcp_wrappers-libs which also uninstall about 900mb files. Since there are some files that are in version 6.2 and 6.3, I decided to uninstall all of those.
However, after doing that I found:
1. system can not boot X11
2. dhcp can not work
3. most of the softerware is gone for example gedit vlc kde, etc.
At the very beginning, I thought it is due to improper nvidia problem, as not booting to X11 is usually due to that. However, this time I can not do that. Therefore, I check
#less /etc/log/xorg.0.log
where [EE] means error. but still I couldn't get the problem solved.
later on I use
#dhclient
to make internet work
and after searching, I found all the things were actually uninstalled. To get them back, I did
# yum grounpinstall "X Window System"
# yum grounpinstall "Desktop"
# yum grounpinstall "Desktop Platform"
# yum grounpinstall "KDE Desktop"
then everything goes back to normal. what a disaster!!
some usefull command
# yum grouplist
shows all the group names
# service NetworkManager stop (start)
