Hexagony, 7 bytes

/)!@.). 

Prints 1 regularly then 2 doubled.

Try it online! or Try it doubled online!

Expanded versions:

Regular:

 / ) ! @ . ) . 

Doubled:

 / ) ! @ . ) . / ) ! @ . ) . . . . . . 

The regular program follows the path: /)!.@ which increments a memory edge (all are initialised to zero) then prints its numeric value. The doubled program follows: /.)/)!@ which increments the edge twice before printing, instead.