Screen allows us to work on multiple windows in unix.
Example: If you are running deployment script on QA and also would like to run deployment script on Dev or Prod, It's a good way to work on multiple unix window sessions where you can do multitasking.
If you are logged in directly into unix os or using putty just type "screen" and hit enter.
A new screen opens with a screen name "screen 0"
You can use this window to work on deploying in QA .
To open another window type "ctrl+a+c"
A new session opens where you can work on deploying Prod.
To switch from screen 1 to screen 0 or vise-versa just type "ctrl+a+a" (Hint: double click "a" quickly)
To close screen 1 or screen 0 just type "Exit".
Hope this helped you to do multitasking.
Don't forget to post your comments.
–Kumar 