Linux - tmux

tmux is great..

for "tabbing" so you can do multiple things over one connection.
for long running processes you want to disconnect from.
for sending the same command to multiple ssh connections.
for

couple useful links:
https://gist.github.com/MohamedAlaa/2961058
https://robots.thoughtbot.com/a-tmux-crash-course

Regarding long-running processes you dont want to die when you disconnect:
When the SSH daemon process associated with your connection decides that your connection is dead, it sends a hangup signal ("SIGHUP") to the login shell. This notifies the shell that you've vanished and that it should begin cleaning up after itself; what happens at this point is shell specific (search its documentation page for "HUP"), but for the most part it will start sending SIGHUP to running jobs associated with it before terminating. Each of those processes, in turn, will do whatever they're configured to do on receipt of that signal. Usually that means terminating. If those jobs have jobs of their own, the signal will often get passed along as well.

*stolen from here: http://serverfault.com/questions/463366/does-getting-disconnected-from-an-ssh-session-kill-your-programs