How do I extract multiple lines of code using Perl regex? - regex

Question

I am trying to extract all of the IP Addresses off of this website: http://www.game-monitor.com/
I want to regex the IP's on that page, extract all of them and display them on the screen.
This is what I have so far, can you tell me what Is wrong and help me?
#!/usr/bin/perl
use HTTP::Request;
use LWP::UserAgent;
print 'Press [1] To Begin: ';
chomp ($begin = <STDIN>);
my $url = 'http://www.game-monitor.com/';
my #ips = ('\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}','\d{1,3}\.\d{1,2}\.\d{1,3}\.\d{1,2}','\d{1,2} \.\d{1,3}\.\d{1,2}\.\d{1,3}','\d{1,2}\.\d{1,2}\.\d{1,2}\.\d{1,3}','\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,2}','\d{1,3}\.\d{1,3}\.\d{1,2}\.\d{1,2}','\d{1,2}\.\d{1,2}\.\d{1,3}\.\d{1,3}','\d{1,2}\.\d{1,2}\.\d{1,2}\.\d{1,2}','\d{1,2}\.\d{1,3}\.\d{1,3}\.\d{1,2}','\d{1,3}\.\d{1,2}\.\d{1,2}\.\d{1,3}');
if ($begin eq 1)
{
my $request = HTTP::Request->new(GET => $url);
my $useragent = LWP::UserAgent->new();
my $response = $useragent->request($request);
my $result = $response->content;
foreach $ip (#ips)
{
if ($result =~ /($ips[0])/ ||
$result =~ /($ips[1])/ ||
$result =~ /($ips[2])/ ||
$result =~ /($ips[3])/ ||
$result =~ /($ips[4])/ ||
$result =~ /($ips[5])/ ||
$result =~ /($ips[6])/ ||
$result =~ /($ips[7])/ ||
$result =~ /($ips[8])/ ||
$result =~ /($ips[9])/
)
{
print "IP: $1 \n";
print "IP: $2 \n";
print "IP: $3 \n";
print "IP: $4 \n";
print "IP: $5 \n";
print "IP: $6 \n";
print "IP: $7 \n";
print "IP: $8 \n";
print "IP: $9 \n";
print "IP: $10 \n";
}
}
}

Answer 1

To simplify multi-line substitutions, use the /s modifier, which in effect tells Perl to pretend the string is a single line--even if it isn't.
see perlre for more detail.
It would be nice if you use module like Regexp::Common::net -- provide regexes for IPv4 addresses instead of writing your own regex for matching ip addresses.
for example try something like,
use Regexp::Common qw/net/;
while (<>) {
print $1, "\n" if /($RE{net}{ipv4})/;
}

Answer 2

Use the /g modifier to match all IPs.
Tip: use -w parameter and strict package to avoid "bad coding style".
#!/usr/bin/perl -w
use strict;
use HTTP::Request;
use LWP::UserAgent;
print 'Press [1] To Begin: ';
chomp (my $begin = <STDIN>);
my $url = 'http://www.game-monitor.com/';
my $ip_regex = '\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}';
if ($begin eq 1)
{
my $request = HTTP::Request->new(GET => $url);
my $useragent = LWP::UserAgent->new();
my $response = $useragent->request($request);
my $result = $response->content;
while ($result =~ /($ip_regex)/g)
{
print "IP: $1 \n";
}
}

Answer 3

#!/usr/bin/perl
use HTTP::Request;
use LWP::UserAgent;
my $url = 'http://www.game-monitor.com/';
my $request = HTTP::Request->new(GET => $url);
my $useragent = LWP::UserAgent->new();
my $response = $useragent->request($request);
my $result = $response->content;
#m = ($result =~ /\b(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})\b/sg);
foreach (#m) {
print "IP: $_\n";
}

Answer 4

I don't really see what you're trying to do with your big array #ips. The first regex already matches all IP addresses (since \d{1,3} means "one to three digits", it already contains IP addresses that have two digits), so you don't need all those permutations with \d{1,2}.
One thing you could do is to surround your regex with \b word boundary anchors to ensure that you don't match 123.123.123.123 within 99123.123.123.12399 or something like it. Also, you're probably aware that your regex would also match something like 999.999.999.999. If that's not a problem because your input won't contain invalid IP addresses, then of course that's just fine.
Finally, you need the /g global modifier so your regex finds not just the first but all occurrences in the string.
In essence, how about doing it like this:
while ($result =~ m/\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b/g) {
print "IP: $&\n";
}