--The time you have before everything blows up, needs to be higher than 15/16 because of the --time it takes for IC2 nukes to blow up after receiving a signal.
seconds = 60

--This stuff here makes it hard to execute the program, you need the argument --"safetyprogramcheck" or else it won't run, so you can't just look trough the files on the --computer and run "exterminatus", either you need to run it trough the self-destruct program --or run it as "exterminatus safetyprogramcheck"
tArgs = { ... }
if #tArgs>0
then
 check = tArgs[1]
else
 check = "rawr"
end

if check=="safetyprogramcheck"
then
--because it's a countdown it will repeat itself all the time, as you can see below (at the --until) it will continue until only 15 seconds are left (the time for IC2 nukes to detonate)
repeat

--This block here makes it look like how it looks, clearing the screen and then using --term.setCursorPos(x,y) to put all the text in the right spot.
term.clear()
term.setCursorPos(13,5)
print("Chicken Farm Self-Destruct")
term.setCursorPos(24,9)
print(seconds)
term.setCursorPos(1,13)
print("Press the button to the left to deactivate")
print("This only works before the last 15 seconds")

--this causes this block of code (from repeat to until) to be done once every second --(sleep(1)), and every second the time left gets one second lower.
seconds = seconds - 1
sleep(1)


--This is the interrupter code. If it gets redstone in the back (when you press the button) --it stops the program by shutting down the computer
if redstone.getInput("back") == false
then
 term.setCursorPos(5,16)
 print("Self-Destruct Aborted")
 term.setCursorPos(5,17)
 print("the chickens will live")
 sleep(10)
 os.shutdown()
end
until
seconds == 15

--this sends a signal to the nukes.
redstone.setOutput("left", true)

--Very similar to the previous repeat block. If you can figure out that one, this one --shouldn't be too hard.
repeat

term.clear()
term.setCursorPos(13,5)
print("Chicken Farm Self-Destruct")
term.setCursorPos(24,9)
print(seconds)
term.setCursorPos(1,13)
print("15 second mark passed. Explosives activated.")
print("Goodbye")

seconds = seconds - 1
sleep(1)
until
seconds == -1

--This has to do with the "safetycheckprogram" thing I mentioned in the start.
else
 print("needs to be run trough the self-destruct program")
end