[arp242]

> One big factor is for performance reasons in shell scripts. At the time, the switch decreased boot times for Debian by 7.5%. Bourne shell features add a lot of overhead and that's not always an acceptable tradeoff.

I seem to recall it was much smaller than that, something like 4% on a 2008 EEE-PC or something like that, but I can't find any numbers on that right now.

The Debian startup scripts were already POSIX; it's not hard to get better performance out of zsh or bash by avoiding expensive processes lookups.

Overall, I consider this to be mostly a myth, or at least extremely simplistic.