hdump is a replacement for a program called 'od'.

hdump uses hex output rather than octal output by default.
to get the following output, type hdump -a <filename>

     0:  68 64 75 6D 70 20 69 73   20 61 20 72 65 70 6C 61   hdump is a repla
    10:  63 65 6D 65 6E 74 20 66   6F 72 20 61 20 70 72 6F   cement for a pro
    20:  67 72 61 6D 20 63 61 6C   6C 65 64 20 27 6F 64 27   gram called 'od'
    30:  2E 0A 0A 68 64 75 6D 70   20 75 73 65 73 20 68 65   ...hdump uses he
    40:  78 20 6F 75 74 70 75 74   20 72 61 74 68 65 72 20   x output rather 
    50:  74 68 61 6E 20 6F 63 74   61 6C 20 6F 75 74 70 75   than octal outpu
    60:  74 20 62 79 20 64 65 66   61 75 6C 74 2E 0A 74 6F   t by default..to
    70:  20 67 65 74 20 61 20 0A   0A                         get a ..
    79: