cmd:od 

$ od -t x1 TuGnrl.txt | grep ' 00 '
0020320 72 65 73 73 69 6f 6e 5d 00 0a 20 0a 20 2d 2d 20
0035060 00 20 62 75 74 20 74 68 65 20 64 6f 63 75 6d 65
0064620 2e 00 0a 0a 3d 3d 20 4e 6f 74 65 73 0a 0a 66 66
0112040 00 0a 0a 23 23 20 57 68 61 74 20 22 64 6f 74 22

od -x means od -t x2, which is not a good selection. *M*: always use "od -t x1"

documented on: 1999.10.10 Sun 16:44:37