If you have multiple servers with similar or identical configurations (such as nodes in a cluster), it's often difficult to make sure the contents and configuration of those servers are identical. It's even more difficult when you need to make configuration modifications from the command line, knowing you'll have to execute the exact same command on a large number of systems (better get coffee first). You could try writing a script to perform the task automatically, but sometimes scripting is overkill for the work to be done. Fortunately, there's another way to execute commands on multiple hosts simultaneously.
Read the full thing at http://www.linux.com/article.pl?sid=06/02/13/1413229
There are some good tools mentioned in the comments of the article. Me, I use the 'Send Input to All Sessions' function in Konsole.