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
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.
R is for ranlib for sorting ar 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.
(unknown author, found on )