Start the process with nohup:
When it is allready started, type disown. (alias disown="kill -CONT %1; disown" or alias disown="bg; disown" to not to have to kill or bg manualy)
Start the process with &! which automatically disowns the process.
Start the program in the background, either with
program & or ^Z bg, then type kill -9 $$ (this one closes also the actual shell).