Using rpmorphan on CentOS 6.4

So I just spent the night compiling and rebuilding RPMs on CentOS to get the exact set up that I would like and now I am left with several *-devel packages along with other development tools and libraries that I do not need any longer. Since this is a production environment, I would prefer to have as little extraneous packages as possible for various reasons.

Enter rpmorphan.

This nifty little tool will list all "orphaned" packages on your system. It would be VERY wise to add the packages that you wish to keep to the exclude list since common programs like wget don't have anything depending on them and will be listed in the output with each package to a line.

Adding a package to the exclude list is simple:

rpmorphan -add-keep wget

The above will add wget to your exclude list.

After you have all the packages you want to keep in your exclude list, removing all orphaned packages with yum is extremely simple:

yum remove `rpmorphan -all | sed ':a;N;$!ba;s/\n/ /g'`

This will run the output of rpmorphan through sed and replace all new lines with a space and use that as the argument list for yum remove. You should be very careful when doing this because I also noticed it listed openssh-server as an orphaned package. Be sure to add that in your exclude list. If not, I feel bad for you and hope you have console or physical access to your box because that would really suck.

Again, I will repeat: Use this at your own risk. If you remove something like your sshd you won't have access to your box. If you're sure that you can handle not doing something like that, this saves a lot of time and stress in the long run. Enjoy!

I would like to acknowledge Zsolt Botykai for his answer on stackoverflow in regards to the sed command. It was very helpful and explained very well.