Aside from the fact that it leaves a window where there is no /bin/sh on the system, because it is not using atomic replacement, that is not what the script is

Aside from the fact that it leaves a window where there is no /bin/sh on the system, because it is not using atomic replacement, that is not what the script is doing. This is a Debian package. /bin/sh has been the Debian Almquist shell for almost three quarters of a decade at this point. * https://lists.debian.org/debian-release/2007/07/msg00027.html https://lists.debian.org/debian-release/2007/07/msg00027.htm... * https://wiki.debian.org/BootProcessSpeedup#Using_a_faster_system_shell https://wiki.debian.org/BootProcessSpeedup#Using_a_faster_sy... * https://wiki.debian.org/DashAsBinSh https://wiki.debian.org/DashAsBinSh * https://wiki.ubuntu.com/DashAsBinSh https://wiki.ubuntu.com/DashAsBinSh * https://wiki.ubuntu.com/DashAsBinSh/Spec https://wiki.ubuntu.com/DashAsBinSh/Spec