> increment the data pointer (to point to the next cell to the right). < decrement the data pointer (to point to the next cell to the left). + increment (increase by one) the int at the data pointer. - decrement (decrease by one) the int at the data pointer. . output the int at the data pointer. , accept one int of input, storing its value in the int at the data pointer. [ if the int at the data pointer is zero, then instead of moving the instruction pointer forward to the next command, jump it forward to the command after the matching ] command. ] if the int at the data pointer is nonzero, then instead of moving the instruction pointer forward to the next command, jump it back to the command after the matching [ command.
Count to 4: +>++>+++>++++<<<.>.>.>.