Have a handful of servers you need to perform the same commands on, e.g., keeping their software packages up to date using aptitude:
aptitude update && aptitude safe-upgrade && aptitude clean
So, you’re performing the same procedure on each host: logging in, executing aptitude, logging out… But WAIT! There’s Cluster SSH for you. 😀
The idea is simple: type in a command into one console and multiplex that input to several remote, i.e., SSH sessions.
For Mac OS X, csshX (also available as homebrew formula) comes in handy as it provides that multiplexing support for Terminal.app.
Open a console in Terminal.app and type in
csshX [email protected] [email protected] [email protected] ...
(providing appropriate [email protected] combinations for your needs, of course).
Then, you enter your commands, e.g.,
aptitude update into the red control console. As you can see in the screenshot, the keystrokes are the sent to all open shells. Updating a bunch of servers became… a piece of cake. Hooray for the lazy admin!