/has address (\S+)/ and do_something($1);
[download]

I'm trying

 
if ($found_addr =~ m/address(.*)\d/){
            print "$1\n";
        }
[download]

But it's cutting off the last digit of the address for some reason.

And I bet you're getting a space in front of the 74. Your "\d" at the end is matching a single digit character and since it's at the end of your parenthesis grabbing match, it's taking the last character - excluding it from your match.

Use JavaFan's regex above and all will be well.

use YAPE::Regex::Explain;
print YAPE::Regex::Explain->new(
qr/address(.*)\d/
)->explain;
__END__
The regular expression:

(?-imsx:address(.*)\d)

matches as follows:

NODE                     EXPLANATION
----------------------------------------------------------------------
(?-imsx:                 group, but do not capture (case-sensitive)
                         (with ^ and $ matching normally) (with . not
                         matching \n) (matching whitespace and #
                         normally):
----------------------------------------------------------------------
  address                  'address'
----------------------------------------------------------------------
  (                        group and capture to \1:
----------------------------------------------------------------------
    .*                       any character except \n (0 or more times
                             (matching the most amount possible))
----------------------------------------------------------------------
  )                        end of \1
----------------------------------------------------------------------
  \d                       digits (0-9)
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------
[download]

So .* (matching the most amount possible) followed by \d, a digit. If you want the digit to be captured, move it inside the parens.

Sweet deal javafan

Last question. What if the output instead of

Using domain server:
Name: 8.8.8.8
Address: 8.8.8.8#53
Aliases: 

google.com has address 74.125.113.147
[download]

Comes out on one line like this:

$ host google.com 8.8.8.8

google.com              A    74.125.113.99
[download]

My previous matching idea still cuts off the last digit. I thought using javafan's and searching for A

/A (\S+)/ and do_something($1);
[download]

Might work but it doesn't seem to. Is there an issue because of the spacing?

Is the question about doing DNS lookups in Perl? In that case use an appropriate module, such as Net::DNS::Lookup, or one of the others you find by querying CPAN for 'DNS Lookup'

If your actual concern is achieving a greater understanding of regular expressions, try:

• Match the constant part of the string, and capture the ip4 that follows ... I'm actually capturing the longest possible string of digits and dots, but you can generally rely on DNS servers to send values that make sense as IP numbers.

my ($ipnum) = ($msg =~ m{has address ([\d\.]+)});
[download]

• Break the regex processing into simple components:

LINE:
for my $line ( split "\n", $dns_data ) {
    next LINE unless index $line, 'has address';
    my ($ipnum) = ($msg =~ m{([\d\.]+));
[download]

Update

You wrote:

    if ($found_addr =~ m/address(.*)\d/){ print "$1\n"; }

    But it's cutting off the last digit of the address for some reason.

Let's go back to basics and discuss this block: IF (the stuff between parentheses is true)THEN DO {the stuff between curly braces}.

the stuff between parentheses is applying a regular expression to the value stored in the variable $found_addr. The regular expression looks for the sequence of characters: 'a', 'd', 'd', 'r', 'e', 's', 's', followed by a wildcard sequence which is captured, followed by a digit which is not captured.

From our knowledge of what was being returned, we know you are capturing a space character, ' ', followed by some digits, a dot, some digits, .... Since the captured sequence is followed by a non-captured digit, the last digit will not be captured. When you look at your printout, you'll notice the IP address is one character to the right, because of the captured space.

If you want to capture the digit, put it within the capturing parentheses. If you want to exlude the space, explicitly specify it outside the parentheses.