Often I start processes in the background, but most of the time, I can not hang around until they are done due to other pressing sysad matters. For security reasons, I have to log off the computer when unattended and that event normally terminates the children of a process.
Here's an example of how I ensure my process(es) will continue regardless of log on status:
#nohup sort esofthub.dat > esofthub.sorted &
OR I can even mail the results to myself.
#nohup sort esofthub.dat > esofthub.sorted | nohup mailx -s "esofthub's sorted file" &