screen

screen
he screen command is an interest-ing utility that is particularly useful if you are accessing a Linux system remotely through an SSH connection. The key benefit of screen is that it allows you to use multiple shell windows from within a single SSH session


>screen
It doesn’t appear any differently. However, it is different because you are now inside of a window within screen.

•Pressing ctrl-a and then ? causes the screen help to be displayed.
•Pressing ctrl-a and then c causes a new screen window to be created. The old window you were working in remains active along with any processes that were running within it. For example, suppose you had top running in a screen window within an SSH session. You need to check your email, but you don’t want to stop running top. To do this, you can open a new window and access your mail. As you do, top stays running in the first window. 
•Pressing ctrl-a and then n toggles between open windows in screen.
•Pressing ctrl-a and then d detaches your screen window and drops you back at your original shell prompt. However, whatever you had running in the window remains running. In fact, you can log completely out of the server and everything will keep working within the detached window.
•Entering screen –r reattaches you to a detached screen window. If you have multiple detached screen windows, you’ll be prompted to specify which one you want to reattach to