[Error] '=' expected

Hello. I am writing my first program with computercraft and I am getting this error and I cannot for the life of me figure out what it means or how to fix it. the full error message is below

bios:338: [string "wrench"]:1: "=" expected

The code is below. it is using a miscperipherals wrench turtle to toggle the state of a redstone power conduit above it every time the redstone signal changes.

While true do
  local event = os.pullEvent("redstone")
  if event=="redstone" then turtle.digUp() end
  end
end

Lua is case-sensitive. While true do should be while true do.

Edit: you also have one too many ends.

Ah. I fixed every other case issue bit I missed that one. I also had an extra "end". now it seems to be working. thanks.