for (@ARGV){$l=length()+1if(length($_)>$l);}
for (sort @ARGV) {
    printf
    qq#%-${l}s %s\n#,"$_:",
    qq-@{[/^\D/o?join '.',unpack('C4',gethostbyname $_)
    :scalar gethostbyaddr(pack('C4',split '\.'),2)]}-;
}