use strict;
my $flag = 0;
my $few = shift || 2;

while (<DATA>) { 
  print $_ if ($flag-- > 0);
  $flag = $few if (/Update certificate/);
}


__DATA__
Useless line before match
Feb 19 15:22:21  206021 152221.684878 7219  INFO: Update certificate for user=(XXX) , updated by XXX
First line after match
Second line after match
Third line after match
Fourth line after match

##</code><code>##

H:\perl> perl 1156056.pl
First line after match
Second line after match

H:\perl>perl 1156056.pl 3
First line after match
Second line after match
Third line after match