Tmux is great. I use it all the time, but sometimes I forget to use it. When I'm in a hurry I forget to start a new tmux session until I'm tailing a log file and then I can't launch a new shell on a remote machine until I ssh again, or stop tailing, start tmux, redo the tail command.

I found a solution somewhere on StackOverflow that goes like this: 

function ssh () { 
/usr/bin/ssh -t "$@" "tmux -2 new -A -s ssh-session || tmux -2 attach || /bin/bash";
}

This changes your regular ssh command into a function. The function does the following.

  1. Passes all your arguments to the ssh program
  2. Tries to create a new session or resume (attach) to a session named ssh-session
  3. If that fails it tries to attach to any session (the first syntax doesn't work on old version of tmux (CentOS))
  4. If that fails then start bash because tmux is probably not installed

Using this bash function is just like using ssh normally. 

ssh root@someserver

If you want to execute code remotely on the machine, then you'll want to reference the full path to the ssh binary. 

/usr/bin/ssh root@someserver "tail -f /var/log/something"