• takes a single value (1,2,4,8 bytes), treats as sequence of bits
• and a small positive integer x
• moves (shifts) each bit x positions to the left
• left-end bit vanishes; right-end bit replaced by zero
• result contains same number of bits as input

  00100111 << 2      00100111 << 8
  --------           --------
  10011100           00000000

** undefined and not recommended for signed quantities.