ホスト名からIPアドレスを調べる

#!/bin/sh
#host2ip.sh host_name

r_host(){
    set -- `host $1`
    shift `expr $# -1`
    case $1 in
        *\(NXDOMAIN\))
            return 1 ;;
        *)
            echo $1
    esac
}

r_nslookup(){
    set -- `/usr/sbin/nslookup $1 2> /dev/null | sed -n '/^Name:/ {
n
p
}'`
    if [ -n "$2" ]; then
        echo $2
    else
        return 1
    fi
}

case `uname` in
    SunOS)
        RESOLVER=r_nslookup ;;
    *)
        RESOLVER=r_host
esac

r_nslookup $1