ドメイン名を逆順にする

#!/bin/sh
#name_reverse.sh

name_reverse () {
    local ret

    while [ $# -gt 0 ]; do
        ret="${1}.${ret}"
        shift
    done
    echo "${ret}" | sed 's/.$//'
}

while read address others; do
    oldifs="${IFS}"
    IFS="."
    reversed=$(name_reverse ${address})
    IFS="${oldifs}"
    echo "${reversed} ${others}"
done 

$ cat 2.txt 
aaa.example.com /index.html

$ cat 2.txt | ./name_reverse.sh 
com.example.aaa /index.html