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I'm running into a strange issue with the unpack() function. I have a command which produces output in binary format which I'm trying to unpack into a hex string for parsing, printing, etc.. It appears that unpack() is removing a byte from the binary data when the hex string is created and I can't figure out why.

I put a small test script together to play around with it a bit and can work around it by writing the binary data to a file first then reading it back in but it seems quite bizarre that doing it the 2 ways would yield different results

use strict; my $data = qx{sg_logs --page=0x34,1 pd1 -H -r > temp.bin}; $data = qx{sg_logs --page=0x34,1 pd1 -H -r }; $data = unpack("H*", $data); open OUTFILE1, ">", "outfile1.txt" or die $!; print "unpacked1: ".$data."\n"; print OUTFILE1 $data; close OUTFILE1; open FILE, "temp.bin" or die $!; binmode FILE; open OUTFILE2, ">", "outfile2.txt" or die $!; while (<FILE>) { print "unpacked2: ".unpack('H*', $_ )."\n"; print OUTFILE2 unpack('H*', $_); } close (FILE); close (OUTFILE2);

When I inspect the 2 output files created, outfile1.txt is always missing a byte in the same location ( 55th byte ) vs. outfile2.txt and of course, it's a byte I'm particularly interested in when parsing the results :) Comparing the 2 file sizes also shows the 2byte difference. Any help would be greatly appreciated!


In reply to unpack() removing data by shnatko

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