I am a total noob at commands. I can do really simple ones like fill-replace stone to air in a specific area, but I can't figure out how to set up the code for things which require more complex logic or combined arguments. At the moment I'm trying to set up a command block to pick a random jungle wood stair block and replace it with an acacia wood stair and keep doing this until I shut it down, to try and give the roof on my large scale building a weathered look. Can somebody please explain how to code that and why all the parts are set up the way they are?
While this isn't vanilla, I would use worldedit for this. Much simpler.
Just select the area with the worldedit wand then do:
//replace junglestair:DATAVALUE 10%acaciastair:DATAVALUE,90%junglestair:DATAVALUE
which will replace 10% of your jungle stairs with acacia stairs. You'll have to do the command once for each stair orientation though. (Replace "DATAVALUE" with the proper number for each orientation)
You'll need the clientside mod or the plugin (on a bukkit/spigot server) to do this though.
Depends, you could have a command block for each jungle stair and then have a
setblock command for it and then just have a
RandomRedstoneAlternator on it (RRA), but that also requires a lot of redstone skill and gets very complex if you have a large roof on your house. Send me a screenshot of the roof and I possibly will be able to send you a schematic of how you could do it.