Este script sirve para buscar en los logs de Postfix 2.9.6 la historia de entrega de los correos que cumplan con el from= y el to= que se indiquen en el primer y segundo argumento del script, respectivamente.

#!/bin/bash

# Configuration variables
REQUIREMENTS="gawk grep"
LOGSOURCES="/var/log/mail.info.1 /var/log/mail.info"

# Check requirements
which $REQUIREMENTS > /dev/null 2>&1 || {
    echo The following required programs were not found:
    for R in $REQUIREMENTS; do
        which "$R" > /dev/null 2>&1 || echo "$R"
    done
    exit 63
}

# Check arguments
[ $# -eq 2 ] || {
    echo Usage: "$0" source_address destination_address
    exit 1
}

# These work for Postfix 2.9.6
function get_filter_from() {
    echo 'BEGIN { FS="[ :]+"} /from=<'$1'>/ && !/NOQUEUE/ { print $8 }'
}

function get_filter_to() {
    echo 'BEGIN { FS="[ :]+"} /to=<'$1'>/ && !/NOQUEUE/ { print $8 }'
}

function awniq() {
    gawk '!a[$0]++'
}

FILTER_FROM=$(get_filter_from "$1")
FILTER_TO=$(get_filter_to "$2")

# For each mail ID found in both from= and to= lines...
for ID in $(grep -f <(gawk "$FILTER_FROM" $LOGSOURCES | awniq) \
  <(gawk "$FILTER_TO" $LOGSOURCES | awniq))
do
    echo ====== $ID ======
    grep -- "$ID" /var/log/{mail.info.1,mail.info}
done