Extract the required substring from another string -Perl

Question

I want to extract a substring from a line in Perl. Let me explain giving an example:

fhjgfghjk3456mm   735373653736
icasd 666666666666
111111111111
<         


        

Answer 1

#!/bin/perl
my $var = 'fhjgfghjk3456mm 735373653736 icasd 666666666666 111111111111';
if($var =~ m/(\d{12})/) {
  print "Twelve digits: $1.";
}