mquote - format MSG as a quotation.
This is a tweaked copy of mquote from mblaze that adds the date of the original message.
#!/bin/sh
Extract the sender
: ${from:=$(mhdr -d -h x-original-from "$1")}
: ${from:=$(mhdr -d -h from "$1")}
: ${from:=Someone}
and the date
pfmt="%a, %d %b %Y %H:%M:%S %z"
: ${date:=$(mhdr -d -h date "$1")}
date="${date:+$(dateconv -f "$pfmt" "$date")}"
printf '%s%s wrote:\n' "${date:+On $date, }" "$from"
Then strip the signature, empty lines and prefix everything with ">"
{ mshow -R "$1" || mshow -h '' -N "$1"; } |
sed -n '/^-- $/,$!p' |
sed -e :a -e '/^\n*$/{$d;N;ba' -e '}' |
sed 's/^/> /'