#!/usr/bin/perl

my $port = $ARGV[0] or die "usage: $0 <portnumber>\n";

while (<DATA>) {
    print if /Port\s+$port/ .. /^#---/ and !/^#---/;
}

__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

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