Re: missing cat data

David W. Tamkin suggested:
>     MATCH
>     :0c # ,,acknowledgement'' is Canadian spelling
>     * ! ^FROM_DAEMON
>     * $ ! ^X-Loop: $LOGNAME
>     * other conditions if any
>     * 1^0 ^Subject:\/.*
>     * 1^0
>     | formail -rkbt -I "Subject: Autoreply${MATCH+ (was $MATCH)}" \
>          -A "X-Loop: $LOGNAME" \
>          -I "Precedence: junk" \
>          -A "X-Comment: Auto-acknowledgement" | \
>          sed -e '1,/^$/ !b' -e "/^$/r $PMDIR/autoack.txt" | \
>          $SENDMAIL -oi -t

Ugh, that second-last line looks ugly!  What does the /^$/ signify?
Is there some subtle distinction in sed between a script in ' '
and one in " " ?

Dave Stone