Let the Linux process run in the background, session disconnected, not exited

Method One:
Nohup Ping www.ibm.com & can change the parent process number of a process
Method Two:
Setsid Ping www.ibm.com can change the parent process number of a process
Method Three:
(Ping www.ibm.com &) To change the process's parent process number
Method Four:
This method is for programs that are already running, CTRL + Z hangs, and BG runs in the background. Then execute the following command
Disown-h%1 ignores the HUP signal for the 1th task in the background.
Method Five: Use screen
SCREEN-DMS NewSession Create a session with a session name of NewSession
Screen-r NewSession Connection Session Ewsession
Ping www.ibm.com & Perform a task that is not affected by session disconnection

Screen-list to list screen sessions
CTRL + A D disconnects a screen session

Reference: http://www.ibm.com/developerworks/cn/linux/l-cn-nohup/

Let the Linux process run in the background, session disconnected, not exited