PUSSH is "Pythonic Ubiquitous SSH" - a command line wrapper script for sending commands to multiple machines in parallel, i.e. in *real time*, with options for controlling the degree of parallelism, timeouts, and node selections. At present, PuSSH is composed of two Python modules, one of which is called explicitly by the other, but this "construct" may change in future versions. PuSSH was designed for usage on networks / clusters / machine farms with lots, or multiple hosts (or indeed over the entire internet, for that matter), ideally wherein SSH is configured with Kerberos or RSA/DSA keys in such a way as to avoid any password authentication. Using PUSSH, you can send the same command via SSH to a range of machines of practically any size, and IN PARALLEL - if the abovementioned conditions for SSH password authentication are met. If not, then some nifty capabilities are also on offer for purely sequential command execution on your target machines.
