/usr/bin/nntpid is in chiark-scripts 5.0.2.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 | #!/usr/bin/perl
# Originally by Simon Tatham
# Modified by Richard Kettlewell, Colin Watson, Ian Jackson
#
# Copyright -2011 Simon Tatham
# Copyright 2011 Richard Kettlewell
# Copyright 2011 Colin Watson
# Copyright 2011 Ian Jackson
#
# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the "Software"),
# to deal in the Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish, distribute, sublicense,
# and/or sell copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
# SOFTWARE IN THE PUBLIC INTEREST, INC. BE LIABLE FOR ANY CLAIM, DAMAGES OR
# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
# ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
# DEALINGS IN THE SOFTWARE.
use Chiark::NNTP;
our $verbose;
($verbose='STDERR', shift @ARGV) if $ARGV[0] eq "-v";
my $c = cnntp_connect($verbose);
$c->banner_reader();
our $code;
# some servers require a GROUP before an ARTICLE command
$c->docmd("GROUP misc.misc");
if(@ARGV == 0) {
  while(<>) {
    s/(^\s+|\s+$)//gs;
    lookup($_);
  }
} else {
  while (@ARGV) {
    my $item = shift @ARGV;
    if($item !~ /[\@:]/ and not defined $group) {
      # maybe a bare group followed by an article number
      die unless @ARGV;
      my $number = shift @ARGV;
      $item = "$item $number";
    }
    lookup($item);
  }
}
$c->docmd("QUIT");
close S;
sub lookup {
  my $mid = shift;
  if($mid !~ /\@/ and $mid =~ /^(.*)[: ](\d+)$/) {
      my ($g, $n) = ($1, $2);
      $c->docmd("GROUP $g");
      $c->docmd("ARTICLE $n");
  } else {
      $mid =~ s/.*\<//;
      $mid =~ s/\>.*//;
      $c->docmd("ARTICLE <$mid>");
  }
  my $fh= 'STDOUT';
  if (-t $fh) {
    my $lesscmd= $ENV{'NNTPID_PAGER'};
    $lesscmd= 'less' unless defined $lesscmd;
    open LESS, "|-", 'sh','-c',$lesscmd or die $!;
    $fh= 'LESS';
  }
  
  while (1) {
    ($code,$_) = $c->getline();
    s/[\r\n]//g;
    last if /^\.$/;
    s/^\.//;
    print $fh "$_\n";
  }
  if ($fh ne 'STDOUT') {
    close $fh or die "$? $!";
  }
}
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