“I’d Like to Have an Argument, Please”Current Working DirectoryCWD, Files, and Import PathsCWD and Command LinesCommand-Line ArgumentsParsing Command-Line ArgumentsShell Environment VariablesFetching Shell VariablesChanging Shell VariablesShell Variable Fine Points: Parents, putenv, and
getenvStandard StreamsRedirecting Streams to Files and ProgramsChaining programs with pipesCoding alternatives for adders and sortersRedirected Streams and User InteractionRedirecting Streams to Python ObjectsThe io.StringIO and io.BytesIO Utility ClassesCapturing the stderr StreamRedirection Syntax in Print CallsOther Redirection Options: os.popen and subprocess
RevisitedRedirecting input or output with os.popenRedirecting input and output with subprocess