local shutil = {}
function shutil.genenv()
 local et = os.genenv()
 for k,v in pairs(shutil) do
  if k ~= "genenv" then
   et[k] = v
  end
 end
 return et
end
function shutil.exec(line)
 local words = {}
 for w in line:gmatch("%S+") do table.insert(words,w) end
 if _ENV[words[1]] then
  local prg = table.remove(words,1)
  local r={pcall(_ENV[prg],table.unpack(words))}
  if r[1] == true then
   table.remove(r,1)
  end
  return table.unpack(r)
 end
 local pth = os.getenv("PATH") or "."
 for d in pth:gmatch("[^:]+") do
  local prg = words[1]
  _,lex = pcall(fs.exists,d.."/"..prg..".lua")
  _,nex = pcall(fs.exists,d.."/"..prg)
  if lex or nex then
   table.remove(words,1)
  end
  if lex then
   return pcall(loadfile(d.."/"..prg..".lua"),table.unpack(words))
  elseif nex then
   return pcall(loadfile(d.."/"..prg),table.unpack(words))
  end
 end
 if line:sub(1,1) == "=" then
  line="return "..line:sub(2)
 end
 local r={pcall(load(line,"shell","bt",_ENV))}
 return table.unpack(r)
end