Arch Linux Install Script (or alis, also known as the Arch Linux executable installation guide and wiki) installs an unattended, automated and customized Arch Linux system.
I suspect this is because certain commands don't use bash, they just use whatever shell is set as the default, and in the arch-chroot that isn't a posix compatible shell. This may also be the case for things further on in the script, I don't know.
I suspect this is because certain commands don't use bash, they just use whatever shell is set as the default, and in the arch-chroot that isn't a posix compatible shell. This may also be the case for things further on in the script, I don't know.