Lua function which creates a hex dump of a binary string.

hex_dump.lua

function hex_dump (str)
    local len = string.len( str )
    local dump = ""
    local hex = ""
    local asc = ""
    
    for i = 1, len do
        if 1 == i % 8 then
            dump = dump .. hex .. asc .. "\n"
            hex = string.format( "%04x: ", i - 1 )
            asc = ""
        end
        
        local ord = string.byte( str, i )
        hex = hex .. string.format( "%02x ", ord )
        if ord >= 32 and ord <= 126 then
            asc = asc .. string.char( ord )
        else
            asc = asc .. "."
        end
    end

    
    return dump .. hex
            .. string.rep( "   ", 8 - len % 8 ) .. asc
end

There's a slight bug with this when the data is exactly aligned to 8 bytes:

0000: 77 ad a4 cc 4b a8 b5 37 w...K..7
0008: 69 02 06 13 af 37 4f a5                         i....7O.