gethostbyname one-liner: Improvements?

cmv has asked for the wisdom of the Perl Monks concerning the following question:

Hi Monks-

I have the need to collapse a nice, easy-to-read-and-maintain perl script into a butt-ugly-but-short one-liner.

Below is what I've evolved from/to. Can TRY02 be made to evolve any further (make it any shorter)?

Thanks

Craig

#!/usr/bin/perl
use strict;
use warnings;

use Data::Dumper;

my $host = 'www.google.com';

#### TRY00: Multi-lines...
my @a = gethostbyname($host);
print "ARRAY: ", Dumper(\@a), "\n";
print "ADDRS:\n", Dumper(unpack('C4', $a[4])), "\n";

#### TRY01: One-liner...
print "ONE:\n", Dumper(unpack('C4', (gethostbyname($host))[4])), "\n";

#### TRY02: One-liner in dotted notation form...
print "TWO:\n",join('.',unpack('C4', (gethostbyname($host))[4])),"\n";
[download]

UPDATE: Thanks to kyle++ and ikegami++ I've learned some new things. Here is the end result that I'm using:

perl -MSocket -e 'print inet_ntoa(scalar(gethostbyname("hostname")))'
[download]

Although I'm impressed with the "". substitution for scalar() (which is called golfing?), I decided to sacrifice the extra characters for understandability (the cost-benefit seems worth it now that the one-liner is this small). Not so butt-ugly now! Many thanks!

Comment on gethostbyname one-liner: Improvements? Select or Download Code

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Re: gethostbyname one-liner: Improvements? by kyle (Abbot) on Jan 20, 2009 at 22:09 UTC
The one you have can be made shorter just by taking out some things that aren't really needed. `print"THR:\n",join('.',unpack'C4',(gethostbyname$host)[4]),$/;` [download] This also loses a couple of characters by using $/ instead of `"\n"`. I've tried a few things, but I haven't gotten anything shorter than that. Maybe these will give you some idea I haven't had myself. `print "KYL:\n",join('.',map ord,split//,(gethostbyname$host)[4]),"\n"; $_=(gethostbyname$host)[4];s/./ord($&).'.'/ge;chop;print "KYL:\n$_\n"; use Socket;print "KYL:\n",inet_ntoa((gethostbyname$host)[4]),"\n"; printf"KYL:\n%d.%d.%d.%d\n",map ord,split//,(gethostbyname$host)[4];` [download] Why do you need this, BTW?	[reply] [d/l] [select]
Re: gethostbyname one-liner: Improvements? by ikegami (Patriarch) on Jan 20, 2009 at 22:26 UTC
Short and simple: `perl -MSocket -E'say inet_ntoa "".gethostbyname shift' domain` [download] Or even shorter: `gethost domain` [download] Or if you want one line of Perl as opposed to a one-liner, `say gethost($host);` [download] Writing program `gethost` and/or function `gethost` is left to you.	[reply] [d/l] [select]
Re: gethostbyname one-liner: Improvements? by jwkrahn (Abbot) on Jan 20, 2009 at 23:33 UTC
$ perl -le'print for `host www.google.com` =~ /\b\d+\.\d+\.\d+\.\d+\b/ +g' 74.125.19.103 74.125.19.147 74.125.19.99 74.125.19.104 [download]	[reply] [d/l]
Re: gethostbyname one-liner: Improvements? by cmv (Chaplain) on Jan 21, 2009 at 15:22 UTC
Folks- Kudos to kyle++ for a bunch of great ideas, particularly using inet_ntoa() - I had no idea... Here's the answer to your question on why I need this... Read more... (661 Bytes) ikegami++ as always. I've learned something new again (but don't yet understand). I do understand why `inet_ntoa(gethostbyname("www.google.com"))` [download] gives me a usage error, but I don't understand why adding the "". makes it work `inet_ntoa("".gethostbyname("www.google.com"))` [download] Unless this is some new form of black magic, it seems that you're simply adding a null in front of that which is returned by gethostbyname(). Why would that have an effect? Lastly, jwkrahn++ for pointing out the unix host(1) command. Unfortunately, the box I'm running this on does not have the command installed. Thanks -Craig	[reply] [d/l] [select]
Re^2: gethostbyname one-liner: Improvements? by ikegami (Patriarch) on Jan 21, 2009 at 16:07 UTC
it seems that you're simply adding a null in front of that which is returned by gethostbyname(). Why would that have an effect? The `concat` operator imposes a scalar context on its arguments. I used `"".` as a golfed form for `scalar()`.	[reply] [d/l] [select]
Re^2: gethostbyname one-liner: Improvements? by kyle (Abbot) on Jan 21, 2009 at 15:43 UTC
The `"".` in ikegami's solution casts the gethostbyname call as a string, but more importantly it puts it in scalar context instead of the list context it would ordinarily be in as a parameter to `inet_ntoa`. We want the scalar context because then `gethostbyname` returns just the packed IP address. In list context it would return more stuff we're not interested in. Using `"".` here is basically a golfy way to say `scalar`.	[reply] [d/l] [select]