> As for efficiency, recall that there were hundreds of /bin/sh scripts in startup, administration, and everyday operation of the system, from all of the /etc/rc.d/ (sub)scripts through things in cron and build systems and package install/deinstall scripts to bunches of commands that were /bin/sh scripts under the covers. So multiply that difference by several orders of magnitude.
And one of the links leads to a savings of 1 second on an eeepc. Not very convincing.