lua cat

local args = { ... }
local file = nil

if #args > 1 then
  print("Usage: cat [file]")
  return
end

if #args == 1 then
  local f = args[1]

  if not fs.exists(f) then
        print("cat: " .. f .. ": No such file")
        return
  end

  if fs.isDir(f) then
        print("cat: " .. f .. ": Is a directory")
  end

  file = fs.open(f, 'r')
end

local line = nil

while true do
  if file ~= nil then
        line = file.readLine()
  else
        line = read()
  end

  if line ~= nil then
        print(line)
  else
        return
  end
end