Dear friends,
I am in fc13, have installed a package, realise lately that its not really useful. that package install a lot of package for dependency.
How can i erase all the package together that was downloaded and installed together with the target package as dependency via yum?
actually i have done it using
#yum erase `cat /var/log/yum.log|grep "Aug 31 22" |awk '{print $5}'|`

as I know when I have installed them.....but is there ant safer and better way?

One thing you could have done is removed them using rpm instead of yum. Since rpm checks for dependencies but doesn't add or delete them like yum it would have errored out if you had tried to delete an rpm that yum previously installed if something else was dependent on it. You'd want to give the whole list to your rpm command at once so it could check the list to see if the dependency is being met by another rpm you're erasing. (If you tried to remove them individually you'd run into dependency hell which is what yum was created to avoid.)