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vdinovi/ruby_hexdump

Created May 10, 2019 21:48
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  1. vdinovi created this gist May 10, 2019.
    24 changes: 24 additions & 0 deletions ruby_hexdump
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,24 @@
    #!/usr/bin/ruby

    # stupid version of hexdump to just read the first n bytes from stdin
    # no args supported
    # useful for when hexdump is not available
    #
    # to print out the first two bytes from a file
    # ./ruby_hexdump 2 < some_file

    ARGV.count == 1 or raise "Usage: ruby_hexdump <num bytes>"
    bytes = ARGV[0].to_i

    buffer = []
    $stdin.each_byte do |byte|
    buffer << ('%02X' % (byte & 0xFF))
    break if buffer.count >= bytes
    end

    buffer.each_slice(16).each_with_index do |hex_row, index|
    $stdout.write '%08X ' % (index * 16 % 0xFFFFFFFF)
    $stdout.write hex_row.join(' ')
    $stdout.write "\n"
    end
    $stdout.flush