/usr/lib/ifhp/extract_pjl is in ifhp 3.5.20-12.1.
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 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 | #!/usr/bin/perl
use strict;
use FileHandle;
use Getopt::Std;
use IO::Select;
use IO::Socket::INET;
sub usage(){
print <<EOF;
 use: $0 [-h host][-p port][-v][-dD][-t timeout]
      $0 [-v][-dD][-u device]
      $0 [-dD][file]*
 Read the PJL status information from a network connection
 device, or files,  (optionally) produce a PJL summary
   -h host  - remote host
   -p port  - port
   -u device - device to query
   -t timeout  - timeout for no input
   -v       - just dump data from device or remote connection
   -d,-D    - debugging enabled. -D is very verbose
  
 PJL commands to request the printer information
	\\033%-12345X
	\@PJL
	\@PJL INFO VARIABLES
	\@PJL INFO ID
	\@PJL INFO CONFIG
	\\033%-12345X
 If there is no additional information after timeout seconds
 the connection is closed.
 PJL Infomration has format:
	\@PJL INFO VARIABLES
	COPIES=1 [2 RANGE]
		 1
		 999
	PAPER=LETTER [19 ENUMERATED]
		 LETTER
		 LETTERR
		 LEGAL
		 FOOLSCAP
		 INVOICE
    ...
    \@PJL ...  < end of section unless it is \@PJL INFO VARIABLES
    We produce:
     pjloption=(fixedname)STRING
     pjloption=(fixedname)RANGE;low,high
     pjloption=(fixedname)ENUMERATED;v1,v2,...
   From the returned information
EOF
	exit(1);
}
$| = 1;
my(@lines,$line,$inbody,$outputline,$port, $host,$dev,$timeout,$verbose);
my $inoptionlisting = 0; # 1 if we are after a line "\@PJL INFO VARIABLES"
                         # and no other "\@PJL ..." line appeared
my $option = "";         # Name of current option
my $optiontype = -1;     # 0: enum, 1: int, 2: float, -1: not found yet
my $numchoices = -1;     # Number of choices, -1: not found yet
my $default = "";        # Default setting
my @choices = ();        # List of possible choices
my $choicesfound = 0;    # How many choices were already found
my $opt = {};
getopts("vdDp:h:t:u:",$opt) || usage();
$port = 9100;
$timeout = 3;
$verbose = 0;
my $debug = 0;
$debug = 1 if $opt->{d};
$debug = 2 if $opt->{D};
$host = $opt->{h} if $opt->{h};
$port = $opt->{p} if $opt->{p};
$timeout = $opt->{t} if $opt->{t};
$dev = $opt->{u} if $opt->{u};
$verbose = 1 if $opt->{v};
my $socket;
if( $host ){
	$socket = IO::Socket::INET->new(
		PeerAddr=>$host,
		PeerPort=>$port,
		Proto=>"tcp",
		Type=>SOCK_STREAM)
	or die "could not connect to $host, port $port";
} elsif( $dev ){
	print "Opening '$dev'\n" if $debug;
	$socket = new FileHandle( "$dev", "w+");
	die "could not open device $dev" if( not $socket );
	print "Open done '$dev'\n" if $debug;
}
if( $socket ){
	print "Sending query\n" if $debug;
	print $socket
	"\033%-12345X" .
	"\@PJL\r\n" .
	"\@PJL INFO VARIABLES\r\n" .
	"\@PJL INFO ID\r\n" .
	"\@PJL INFO CONFIG\r\n" .
	"\033%-12345X"
		or die "write to device failed";
	my $s = IO::Select->new();
	my $in = "";
	my $input;
	while(1){
		$s->add($socket);
		print "starting wait, timeout $timeout\n" if $debug;
		my @ready = $s->can_read($timeout);
		print "ready '" . scalar @ready . "'\n" if $debug;
		last if( @ready == 0 );
		my $len =  sysread $socket, $input, 1024;
		print "Read '$len'\n" if $debug > 1;
		last if not $len;
		$input =~ s/[\015\014]//g;
		print " INPUT '$input'\n" if $debug > 1;
		$in .= $input;
	}
	close($socket);
	@lines = map( "$_\n", split("\n",$in ));
} else {
	@lines = <> or die "No input";
}
print "Input " .  join("", @lines) . "\n" if $debug;
if( $verbose ){
	print join("", @lines);
	exit(0);
}
$inbody = 0;
$outputline = "";
foreach (@lines){
	chomp;
	s/\015//;
	$line = $_;
	print "# INPUT $_ \n" if $debug;
	if( /^\@PJL/  ){
		if( /^\@PJL\s+INFO\s+VARIABLES/  ){
			$inbody = 1;
		} else {
			$inbody = 0;
		}
	}
	if( not $inbody and $outputline ){
		print STDERR "# Unexpected end of information\n";
		print $outputline . "\n";
		exit(1);
	}
	next if( not $inbody );
	if ($line =~ m/^\s*([\w\s:]*)\s*=\"?([\w\.\?]*)\"?\s*\[([0-9]*)\s*(\w*)\s*(\w*)\]/
		or
		$line =~ m/^\s*([\w\s:]*)\s*=\"?(.*)\"?\s*\[\s*(\w*)\s*\]/
		#                option       default           numchoices
		) {
		# Option header
		if( $outputline ){
			print STDERR "# Incomplete option '$outputline'\n";
			exit(1);
		}
		my $typestr;
		my $modifierstr;
		
		($option, $default, $numchoices, $typestr, $modifierstr) = 
		    ($1, $2, $3, $4, $5);
		if( $numchoices eq "STRING" ){
			$typestr = $numchoices;
			$numchoices = "";
		}
		print "# Option: '$option', Default '$default', Numchoices '$numchoices', Typestr '$typestr', Modifier '$modifierstr'\n"
			if $debug;
		if ($modifierstr eq "READONLY") { # Ignore READONLY options
		    $numchoices = -2;
		    print "# WARNING: Read-only option '$option', ignored!\n";
			next;
		}
		$choicesfound = 0;
		@choices = ();
		my $optstr = $option;
		$optstr =~ s/\W/_/g;
		$outputline = $optstr . "=";
		if( $optstr ne $option ){
			$optstr = "($option)";
			$optstr =~ s/\s/+/g;
			$outputline .= $optstr;
		}
		if (($modifierstr eq "STRING") || ($typestr eq "STRING")) { 
			$outputline .= "STRING;";
			print $outputline . "\n";
			$outputline = "";
			$numchoices = -2;
			next;
		}
		if ($numchoices == 1 && $typestr eq "ENUMERATED") { # Ignore enumerated with 1 choice
		    $numchoices = -2;
		    print "# WARNING: enumerated option '$option' with one choice, ignored!\n";
			$outputline = "";
			$numchoices = -2;
			next;
		}
		$outputline .= "$typestr;";
	} else {
		$choicesfound = @choices;
		print "# option: '$line', numchoices '$numchoices', found '$choicesfound'\n" if $debug>1;
		next if( $numchoices < 0 );
		$line =~ s/\s//g;
		next if( $line eq "" );
		if( not $numchoices or ($numchoices <= $choicesfound)  ){
			print "# Unexpected option '$line'\n";
			next;
		}
		push @choices, $line;
		if( @choices == $numchoices ){
			print $outputline . join(",",@choices). "\n";
			$outputline = "";
		}
	}
}
if( $outputline ){
	print STDERR "# Unexpected EOF\n";
	print $outputline . "\n";
	exit(1);
}
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