This poem must be read aloud in order for the joke to be apparent. Each symbol goes by it's name in the Unix world. I've also transcribed the verbal text of the joke beneath the joke itself.

The Joke

	<>!*''#
	^"`$$-
	!*=@$_
	%*<>~#4
	&[]../
	|{,,SYSTEM HALTED

The sounds

	Angle angle bang splat tick tick hash,
	Caret quote back-tick dollar dollar dash,
	Bang splat equal at dollar under-score,
	Percent splat angle angle tilde number four,
	Ampersand bracket bracket dot dot slash,
	Vertical-bar curly-bracket comma comma CRASH!

Okay, someone else add some more poetry on to this one!!!

The ABC's of UNIX:

A is for awk, which runs like a snail, and
B is for biff, which reads all your mail.

C is for cc, as hackers recall, while
D is for dd, the command that does all.

E is for emacs, which rebinds your keys, and
F is for fsck, which rebuilds your trees.

G is for grep, a clever detective, while
H is for halt, which may seem defective.

I is for indent, which rarely amuses, and
J is for join, which nobody uses.

K is for kill, which makes you the boss, while
L is for lex, which is missing from DOS.

M is for more, from which Less was begot, and
N is for nice, which it really is not.

O is for od, which prints out things nice, while
P is for passwd, which reads in strings twice.

Q is for quota, a Berkeley-type fable, and
R is for ranlib, for sorting ar sic table.

S is for spell, which attempts to belittle, while
T is for true, which does very little.

U is for uniq, which is used after Sort, and
V is for vi, which is hard to abort.

W is for whoami, which tells you your name, while
X is, well, X, of dubious fame.

Y is for yes, which makes an impression, and
Z is for zcat, which handles compression.