Perl Unpack function. Hex an input file

[learingperl01]

Hello all,

pretty new to unpack function in Perl. I am trying to take an input file read it and use unpack to create a HEX output of the entire file. The only problem is that when I compare the HEX values of the file I am reading with the output of unpack some of the value are not correct, for some reason some hex values are off.

Example:
if my in file viewed in a HEX viewer shows the first the 8 bytes as 19 00 1d 12 33 0d 0a 00

The output of the unpack are shown as
19 00 1d 12 33 65 44 32

I was wondering if someone could let me know if I am going at this the correct way or if I am missing something in my code that maybe converting certain bytes incorrectly.

Thanks,

#!/usr/bin/perl

use strict;
use warnings;

my($strInputFile) = $ARGV[0];

if ($#ARGV ne "0")
{
 print "\n";
 print "Usage:\n";
 print "bin_hex.pl filename\n";

 exit;
}

if (open(INPUTFILE, "< $strInputFile"))
{
 binmode(INPUTFILE);
 while (<INPUTFILE>)
 {
  my $strBytes = $_;
  print unpack("H32", $strBytes);
 }

 close(INPUTFILE);
}
else
{
 print "ERROR! Cannot open file $strInputFile\n";
}

 

[Kirsle]

I would probably tackle this kind of problem by having it read one byte at a time, as an integer, and converting it to hex.

i.e.

open (BIN, "file.bin");
binmode BIN;

my $buffer;
while (read(BIN,$buffer,1)) {
   my $hex = sprintf("%02h", unpack("C",$buffer));
   print "$hex";
}

close (BIN);
print "\n";

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perl -e '$|=$i=1;print" oo\n<|>\n_|_";x:sleep$|;print"\b",$i++%2?"/":"_";goto x;'

 

[Kirsle]

Actually that'd be %02x on the sprintf line.

Here's an example:

[kirsle@firefly ~]$ cat hello.bin 
hello
world!
[kirsle@firefly ~]$ perl
open (BIN, "hello.bin");
binmode BIN;
my $buffer;
while (read(BIN,$buffer,1)) {
	my $hex = sprintf("%02x",unpack("C",$buffer));
	print "$hex ";
}
print "\n";
close (BIN);
__END__
68 65 6c 6c 6f 0a 77 6f 72 6c 64 21 0a 
[kirsle@firefly ~]$ hexdump -C hello.bin 
00000000  68 65 6c 6c 6f 0a 77 6f  72 6c 64 21 0a           |hello.world!.|
0000000d

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perl -e '$|=$i=1;print" oo\n<|>\n_|_";x:sleep$|;print"\b",$i++%2?"/":"_";goto x;'

 

[zenstudies]

This file will output a line of hex and then directly below it the line in ascii.

---------------------------
#! /usr/bin/perl

use warnings;
use strict;

open (my $file, '<', $ARGV[0]) or
die "Unable to open $ARGV[0]: $!";

binmode $file;


while(read ($file, my $buffer,32))
{
for my $char (split '', $buffer)
{
my $hex = unpack 'H*', $char;
print "$hex "
}
print "\n";

for my $char (split '', $buffer)
{
my $ord = ord($char);
print $ord > 31 && $ord < 128 ? $char : '.';
print " ";
}
print "\n";
print "\n";
}
-------------------------------------