The `nice` command alone (a.k.a. setpriority) doesn't do much. The verynice() function is similar to saying: #!/bin/sh exec ionice -c3 nice "$@" Since

The `nice` command alone (a.k.a. setpriority) doesn't do much. The verynice() function is similar to saying: #!/bin/sh exec ionice -c3 nice "$@" Since it uses SCHED_IDLE i/o priority too. It's intended to ensure that no matter how much you bog down the system with i/o and cpu usage, my Emacs session and login shells will remain interactive and in control.