startup.lua

local ec = peripheral.find "ender_chest"
local ecinv = peripheral.find "minecraft:ender chest"

local z = ...
if z then
    ec.setFrequency(tonumber(z, 16))
    return
end

for i = 0, 0xFFF do
    ec.setFrequency(i)
    local count = 0
    for _, s in pairs(ecinv.list()) do
        count = count + s.count
    end
    if count > 0 then
        print(os.date "!%X", table.concat(ec.getFrequencyColors(), "/"), ("0x%03x"):format(i), count)
    end
    sleep(0.1)
end