HowTo Keep Processes Running After Logging Out Using: "setsid"
HowTo Set The Session ID (SID) and Process Group ID (PGID)
The "setsid" command allows one to set a new "Session ID" (SID) and "Process Group ID" (PGID) for a given command. This can be quite useful when logging out from a shell environment and keeping a process up and running. Since the process is running in an entirely different "session", it should not be effected by the log out and shell termination sequence.
One can also use the "nohup", "disown" and "screen" commands to provide similar results.