Greg,
Good point. The BSD sed man page says:
"
The
-E
,
-a
and
-i
options are non-standard FreeBSD extensions and may not be available on other operating systems."
So perhaps a better solution is to not use the -i option at all and be POSIX compliant?
Informally looking through some of the code, this was the only use of the -i option that I found.
wlh