#! perl -slw
use strict;

sub port_definition{
	my( $port, $def ) = shift;
	#open FILE, '<', ....
	local $/ = '#-------------------------------------------';
	1 until ($def = <DATA>) =~ m[Port $port];
	return $def;
}

print port_definition 123 ;

__DATA__
Port 119 NNTP

* Microsoft Ports-Microsoft Exchange supports a News server running at this port.
* RFC977
* RFC1036

#-------------------------------------------

Port 120 CFDP

(UDP) Coherent File Distribution Protocol (CFDP)

* RFC1235

#-------------------------------------------

Port 123 NTP

(UDP) NTP (Network Time Protocol)

* RFC2030
* RFC1129

#-------------------------------------------