perl -e '$_ = join "", map { chr() } 0..255; s/\W//g; print' | od -txC -a

##</code><code>##

0000000    30  31  32  33  34  35  36  37  38  39  41  42  43  44  45  46
           0   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F
0000020    47  48  49  4a  4b  4c  4d  4e  4f  50  51  52  53  54  55  56
           G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V
0000040    57  58  59  5a  5f  61  62  63  64  65  66  67  68  69  6a  6b
           W   X   Y   Z   _   a   b   c   d   e   f   g   h   i   j   k
0000060    6c  6d  6e  6f  70  71  72  73  74  75  76  77  78  79  7a    
           l   m   n   o   p   q   r   s   t   u   v   w   x   y   z    
0000077

##</code><code>##

perl -CS -e '$_ = join "", map { chr() } 0..255; s/\W//g; print $_,$/'

# (produces the same output as the first one-liner above)

perl -CS -e '$_ = join "", map { chr() } 0..256; s/\W//g; print $_,$/'

# (produces very different output)