#!/bin/bash

for fname in `ls -1tr /home/kaz/tmp/message*[0-9].gz`
do
        echo $fname
        #echo $fname | sed -e 's|\(^/.*\)\.\([[:digit:]][[:digit:]]\?\)\.\(gz$\)|\2|g'
        num=`echo $fname | sed -e 's|\(^/.*\)\.\([[:digit:]][[:digit:]]\?\)\.\(gz$\)|\2|g'`
        fname_date=`date --date "${num} day ago" '+%Y%m%d'`
        echo ${fname//$num.gz/$fname_date.gz}
done