shl() shift its argument bitwise to the left
The shl-function (shl stands for shift left) treats its first argument as a binary number and shifts it to the left as specified by its second argument, filling up the gaps with zeroes. So bin$(shl(0b11011,4)) returns 110110000 (the example uses bin$ and a number with base 2).
Please note: as the argument of the function is converted to a 32-bit integer, all results are also confined to this range.
print "Some powers of two:"
for i=0 to 5
This will print the powers of two from 1 to 32, because the left-shift operation is equivalent to a multiplication with two.
and, or, bitnot, shr