http://www.perlmonks.org?node_id=111481

subroutine to print a hexdump of a string. I saw some discussion in the CB about needing such a thing.

Update: Also see HexView by OeufMayo.

sub hdump { my $offset = 0; my(@array,$format); foreach my $data (unpack("a16"x(length($_[0])/16)."a*",$_[0])) { my($len)=length($data); if ($len == 16) { @array = unpack('N4', $data); $format="0x%08x (%05d) %08x %08x %08x %08x %s\n"; } else { @array = unpack('C*', $data); $_ = sprintf "%2.2x", $_ for @array; push(@array, ' ') while $len++ < 16; $format="0x%08x (%05d)" . " %s%s%s%s %s%s%s%s %s%s%s%s %s%s%s%s %s\n"; } $data =~ tr/\0-\37\177-\377/./; printf $format,$offset,$offset,@array,$data; $offset += 16; } }
Update: Fixed the map() in a void context problem. Thanks merlyn. For the curious, it sort of evolved into a void context as I cleaned up the subroutine before posting it to perlmonks.

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Re: Hex dump
by merlyn (Sage) on Sep 11, 2001 at 02:01 UTC
    I really dislike the "void map" there, for things like:
    map {$_ = sprintf('%2.2x',$_)} @array;
    What's wrong with simply:
    $_ = sprintf "%2.2x", $_ for @array;
    It even comes in at fewer characters, as well as running faster!

    -- Randal L. Schwartz, Perl hacker

Re: Hex dump
by tokai (Initiate) on Aug 29, 2015 at 00:06 UTC

    I liked the output of this function, so I used it for debugging purposes for a while... but in the end I wrote my own simplified variant with some other ideas from here and there which produces exactly the same output:

    sub hexdump($) { my $offset = 0; foreach my $chunk (unpack "(a16)*", $_[0]) { my $hex = unpack "H*", $chunk; # hexadecimal magic $chunk =~ tr/ -~/./c; # replace unprintables $hex =~ s/(.{1,8})/$1 /gs; # insert spaces printf "0x%08x (%05u) %-*s %s\n", $offset, $offset, 36, $hex, $chunk; $offset += 16; } }