Break up a variable

[qwicker]

hello, I am quite new to perl and i am not sure how do do something. I have a string $ip = "153.104.232.232" for example, and i need to compare the first 8 characters of to another IP address. Basically i want to check if that IP is part of the correct subnet. So i need the function that will "cut up" $ip and only return "153.104." so that i can compare it. How can i do this? Thank you

Example:
$ip = "153.104.233.234";
cut-up(8) $ip;
if ($ip=="153.104."){
blah blah

 

[TonyGroves]

[tt]substr($ip,8)[/tt]

 

[TonyGroves]

Sorry, that should have been:
[tt]substr($1p,0,8)[/tt]

 

[TonyGroves]

or even:
[tt]substr($ip,0,8)[/tt]

 

[MikeLacey]

There are a few ways to do this. My favourite would be this.

$ip = "153.104.233.234";

$ip_copy = $ip;
$ip_copy =~ /\./; # look for a '.'
$first = $`; # everything before the '.'
$ip_copy = $'; # save everything *after* that '.'
$ip_copy =~ /\./; # look for another '.'
$second = $`; # everything before the '.'

print "first = $first and second = $second\n";


Mike

I am not scrutable.

Want great answers to your Tek-Tips questions? Have a look at faq219-2884

 

[knights199]

Using a regex

my $ip = "153.104.233.234";
my ($octets) = $ip =~ /^(\d+\.\d+)/; # apply match operator to $ip
# anything captured ("153.104") is stored in $octets

 

[PaulTEG]

$octet1="103";
$octet2="94";
my (@octets)=split (/\./, $ip);
if (($octet[0]=$octet1) && ($octet[1] eq $octet2))
#  we have a match
}

TIMTOWTDI ;-)

Spend an hour a week on CPAN, helps cure all known programming ailments ;-)

 

[duncdude]

[b]#!/usr/bin/perl[/b]

$match = '[b][red]153.104[/red][/b]';

@addresses = qw(  [b][blue]143.104.233.234  153.102.233.234  153.104.233.234  153.100.233.234  153.104.233.234[/blue][/b]  );

foreach $ip (@addresses) {
  @octets = split(/\./, $ip);
  if ( "$octets[0].$octets[1]" eq $match ) {
    print "[b][green]*** MATCH ***[/green][/b]\n";
  } else {
    print "NO MATCH!\n";
  }
}

Kind Regards
Duncan

 

[PaulTEG]

Dunc, do you need to escape that period in double quotes?

Spend an hour a week on CPAN, helps cure all known programming ailments ;-)

 

[duncdude]

Hi Paul

Doesn't appear to be necessary - i have tested the script & it seems to work fine

Kind Regards
Duncan

 

[PaulTEG]

np
--Paul

 

[MikeLacey]

What about:

my ($oct1, $oct2, $oct3, $oct4 ) = split (/\./, $ip);

Mike

I am not scrutable.

Want great answers to your Tek-Tips questions? Have a look at faq219-2884

 

[Corwinsw]

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

my $IP1 = "192.168.3.123";
my $IP2 = "192.167.3.123";
my $IP3 = "195.164.3.12";

sub IPsort{
   pack('C4' => $a =~
      /(\d+)\.(\d+)\./)
   cmp
   pack('C4' => $b =~
      /(\d+)\.(\d+)\./)
}

my @arr = sort IPsort ($IP1, $IP2, $IP3);

foreach (0 .. $#arr) {
   print "$arr[$_]\n";
}

Corwin