len(dir(os path) on windowsmore on unix nested module within os the content of these two modules may vary per python version and platform for exampleos is much larger under cygwin after building python from its source code there (cygwin is system that provides unix-like functionality on windowsit is discussed further in "more on cygwin python for windowson page )/python exe python ( : feb : : [gcc (cygming specialgdc using dmd )on cygwin type "help""copyright""creditsor "licensefor more information import sysos len(dir(sys) len(dir(os) len(dir(os path) as ' not going to demonstrate every item in every built-in modulethe first thing want to do is show you how to get more details on your own officiallythis task also serves as an excuse for introducing few core system scripting conceptsalong the waywe'll code first script to format documentation python system modules most system-level interfaces in python are shipped in just two modulessys and os that' somewhat oversimplifiedother standard modules belong to this domain too among them are the followingglob for filename expansion socket for network connections and inter-process communication (ipcthreading_threadqueue for running and synchronizing concurrent threads timetimeit for accessing system time details subprocessmultiprocessing for launching and controlling parallel processes signalselectshutiltempfileand others for various other system-related tasks third-party extensions such as pyserial ( serial port interface)pexpect (an expect work-alike for controlling cross-program dialogs)and even twisted ( networking system tools