cd=fs.cd
rm=fs.rm
mkdir=fs.mkdir
function ls(p)
 for k,v in ipairs(fs.list(p)) do print(v) end
end
function cat(p)
 local f=io.open(p)
 print(f:read("*a"))
 f:close()
end
function ps(f)
 local f=f or ""
 for k,v in ipairs(os.tasks()) do
  if v:find(f) then
   print(tostring(k).."\t"..tostring(v))
  end
 end
end
function mem()
 print(" \tTotal\tFree\tUsed")
 io.write("Mem\t")
 io.write(tostring(math.floor(computer.totalMemory()/1024)).."K\t")
 io.write(tostring(math.floor(computer.freeMemory()/1024)).."K\t")
 print(tostring(math.floor((computer.totalMemory()-computer.freeMemory())/1024)).."K\t")
end