Do you ever wanted to download somethings, start the encode of the latest video of the brides of the sister-in-law of your brother’s friend, on a distant computer? Or juste keep you’r work on this computer, without keep an opened terminal with the active SSH session?
If you don’t know “Screen” on linux, let’s go! 
Screen is a windows manager in text mode for you, geek friends, followers of the term! 
To keep process without kill them when you shut your SSH connection out, it’s easy:
You just have to log on your distant machine:
ssh user@machine
Next, launch screen:
screen
You can now do what you want on your machine: wget, torrent, encode, etc…
When you want to log of, just ctrl+A then d (to “drop” the window).
You can so exit the shell:
exit
You can now return to your occupations and habbits 
When you want to return back on the distant computer to see what’s happen now, you have to relog on as previously and type:
screen -r -d
It’s not complicated et mostly cool!
Slides/exercices/livres concernant mes cours à Linköping!