The old version had a race between the time that the old file was
cp'ed to acct.0 and the time that 'sa -s' was run that prevented
the commands that occurred in the meantime from being backed up.
It's also arguable that the old version was inefficient in using
cp which can be a problem on a space-constrained system.
This version avoids both problems, albeit it's considerably more
complicated. The advantage of putting the log rotation in the rc.d
script is that it can handle the _enable and _file questions without
having to do gymnastics to discover either value in the periodic script.
As a side effect of reviewing the rc.d script I cleaned it up a bit.
7cea22540c