總結自 http://askubuntu.com/questions/562911/how-to-execute-a-task-in-backgroundubuntu
1. 啓動時 $ zathura a.pdf &spa
2.io
$ zathura a.pdfpdf
$ # press Ctrl+z總結
$ bgdi
3. nohup zathura a.pdf &co
4. background
$ zathura a.pdf
$ # press Ctrl+z
$ bg
$ disown %%