linux, ctrl+z, bg, fg - fun

foreground, background

ctrl + z    = will suspend the currently foregrounded program
jobs        = see suspended / running jobs with number
bg          = will run in background (the most recently suspended program)
              (use bg %2 with the job number, which you can check with jobs)
fg          = will bring to foreground the most recently suspended program

retroactive nohup

ctrl-z to interrupt the process and then run bg to make it run in the background.

bg

You can show a numbered list all processes backgrounded in this manner with jobs.

disown -h %1 (replace 1 with the process number output by jobs) to detach the process from the terminal.

screen usage

Start with:

screen

Create new window with: Ctrl-A C
Jump to next existing window: Ctrl-A N
Detach from all windows: Ctrl-A D

PS: you can start a screen in one machine and then use ssh within the windows to access whatever server workers there are.
    Detaching will return you to the first machine.
    
Check what is running:
    screen -Q windows
    screen -ls
    
Reconnect with:

screen -r