shebang

问题 At the beginning of all my executable Python scripts I put the shebang line: #!/usr/bin/env python I'm running these scripts on a system where env python yields a Python 2.2 environment. My scripts quickly fail because I have a manual check for a compatible Python version: if sys.version_info < (2, 4): raise ImportError("Cannot run with Python version < 2.4") I don't want to have to change the shebang line on every executable file, if it's possible; however, I don't have administrative access

问题 I used to use the shebang #!/usr/bin/env python When is it better to use #!/usr/bin/python What is the exact difference between them? 回答1: #!/usr/bin/python is hardcoded to always run /usr/bin/python , while #!/usr/bin/env python will run whichever python would be default in your current environment (it will take in account for example $PATH , you can check which python interpreter will be used with which python ). The second way ( #!/usr/bin/env python ) is preferred , as it's not dependent

问题 I try to build scripts that work everywhere and always. For this I use a custom-built python, which is always in the parent directory relative to the script. This way I could load my package on an USB-stick and it would work everywhere, regardless of where the stick is mounted and whether python is installed or not. However, when I use #!../python then it works only when the script gets invoked from its directory, which is of course not acceptable. Is there a way to do this or is this

问题 #!/usr/bin/env python I put that at the top of a script. I've seen that should make the script runnable from the command line without the need for python programname.py . Unless I'm misunderstanding I should be able to use programname.py as long as I have the above line at the top of the script. Is this correct? It isn't working for me I just get an error indicating that I would have to use python at the beginning of the 'call'. 回答1: Universal running of Python scripts You can pretty much

问题 I'm trying to understand one of the answers to this question: Cannot pass an argument to python with "#!/usr/bin/env python" #!/bin/sh ''''exec python -u -- "$0" ${1+"$@"} # ''' This works well, but I do not understand why it works with four ticks at the beginning of that line rather than three. In addition, why the hash near the end of that string? 回答1: Python supports triple-quoted strings: '''something''' Shell supports only single-quoted strings: 'something' By using four quotes, sh sees

问题 In a script you must include a #! on the first line followed by the path to the program that will execute the script (e.g.: sh, perl). As far as I know, the # character denotes the start of a comment and that line is supposed to be ignored by the program executing the script. It would seem, that this first line is at some point read by something in order for the script to be executed by the proper program. Could somebody please shed more light on the workings of the #! ? I'm really curious

问题 In a script you must include a #! on the first line followed by the path to the program that will execute the script (e.g.: sh, perl). As far as I know, the # character denotes the start of a comment and that line is supposed to be ignored by the program executing the script. It would seem, that this first line is at some point read by something in order for the script to be executed by the proper program. Could somebody please shed more light on the workings of the #! ? I'm really curious

问题 I have set up a local Perl web environment on my Windows machine. The application I'm working on is originally from a Linux server, and so the shebang for source .pl files look like so: #!/usr/bin/perl This causes the following error on my Windows dev machine: (OS 2)The system cannot find the file specified. Is it possible to change my Apache 2 conf so that the shebang is ignored on my Windows machine? Of course I could set the shebang to #!c:\perl\bin\perl.exe , that much is obvious; but the

问题 I had seen this line #!/usr/bin/env node at the beginning of some examples in nodejs and I had googled without finding any topic that could answer the reason for that line. The nature of the words makes search it not that easy. I'd read some javascript and nodejs books recently and I didn't remember seeing it in any of them. If you want an example, you could see the RabbitMQ official tutorial, they have it in almost all of their examples, here is one of them: #!/usr/bin/env node var amqp =

问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: Set up Python on Windows to not type python in cmd When I use python on Linux, or even Mac OS from command line, I take advantage of the shebang and run some of my scripts directly, like so: ./myScript.py . I do need to give this script executable permissions, but that is all. Now, I just installed Python 3.1.2 on Windows 7, and I want to be able to do the same from command line. What additional steps do I need