it to find an interpreter for running the program code in the rest of the file alsonote that this file is called simply brianwithout the py suffix used for the module file earlier adding py to the name wouldn' hurt (and might help you remember that this is python program file)but because you don' plan on letting other modules import the code in this filethe name of the file is irrelevant if you give the file executable privileges with chmod + brian shell commandyou can run it from the operating system shell as though it were binary program (for the followingeither make sure the current directoryis in your system path settingor run this with /brian)brian the bright side of life the unix env lookup trick on some unix systemsyou can avoid hardcoding the path to the python interpreter in your script file by writing the special first-line comment like this#!/usr/bin/env python script goes here when coded this waythe env program locates the python interpreter according to your system search path settings (in most unix shellsby looking in all the directories listed in your path environment variablethis scheme can be more portableas you don' need to hardcode python install path in the first line of all your scripts that wayif your scripts ever move to new machineor your python ever moves to new locationyou must update just pathnot all your scripts provided you have access to env everywhereyour scripts will run no matter where python lives on your system in factthis env form is generally recommended today over even something as generic as /usr/bin/pythonbecause some platforms may install python elsewhere of coursethis assumes that env lives in the same place everywhere (on some machinesit may be in /sbin/binor elsewhere)if notall portability bets are offthe python windows launcher#comes to windows note for windows users running python and earlierthe method described here is unix trickand it may not work on your platform not to worryjust use the basic command-line technique explored earlier list the file' name on an explicit python command line: :\codepython brian the bright side of life in this caseyou don' need the special #comment at the top (although python just ignores it if it' present)and the file doesn' need to be given executable privileges in factif you want to run files portably between unix and microsoft windowsyour life how you run programs