When filling one stair with another stair type the new stairs are turned the direction facing the player.
my command was "/fill ~ ~-1 ~ ~20 ~15 ~-10 sprice_stairs 0 replace oak_stairs"
Comments 2
Use
/fill ~ ~-1 ~ ~2 ~5 ~5 spruce_stairs 0 replace
/fill ~ ~-1 ~ ~2 ~5 ~5 spruce_stairs 1 replace
/fill ~ ~-1 ~ ~2 ~5 ~5 spruce_stairs 2 replace
/fill ~ ~-1 ~ ~2 ~5 ~5 spruce_stairs 3 replace
.../fill ~ ~-1 ~ ~2 ~5 ~5 spruce_stairs 0 replace
/fill ~ ~-1 ~ ~2 ~5 ~5 spruce_stairs 1 replace
/fill ~ ~-1 ~ ~2 ~5 ~5 spruce_stairs 2 replace
/fill ~ ~-1 ~ ~2 ~5 ~5 spruce_stairs 3 replace
...
Please provide the excact commands you've used.