the python windows launcher this appendix describes the new windows launcher for pythoninstalled with python automaticallyand available separately on the web for use with older versions though the new launcher comes with some pitfallsit provides some much-needed coherence for program execution when multiple pythons coexist on the same computer 've written this page for programmers using python on windows though it is platform-specific by natureit' targeted at both python beginners (most of whom get started on this platform)as well as python developers who write code to work portably between windows and unix as we will seethe new launcher changes the rules on windows radically enough to impact everyone who uses python on windowsor may in the future the unix legacy to fully understand the launcher' protocolswe have to begin with short history lesson unix developers long ago devised protocol for designating program to run script' code on unix systems (including linux and mac os )the first line in script' text file is special if it begins with two-character sequence#!sometimes called shebang (an arguably silly phrase promise not to repeat from here on gives brief overview of this topicbut here' another look in unix scriptssuch lines designate program to run the rest of the script' contentsby coding it after the #!--using either the directory path to the desired program itselfor an invocation of the env unix utility that looks up the target per your path settingthe customizable system environment variable that lists directories to be searched for executables#!/usr/local/bin/python script' code run under this specific program #!/usr/bin/env python script' code run under "pythonfound on path