string length comparer
SED, 45 (43 + 2 for the -n flag)

s/./a/g
h
n
s/./b/g
G
:a
s/b\(.*\)a/\1/
ta


Expects input as two separate lines, outputs the difference in unary, using "a" or "b" to indicate the longer string. run with sed -n.