[Tutor] "#!/usr/bin/env python" vs "#!/usr/local/bin/python"

[Bill Campbell]

On Thu, Jun 14, 2007, Rolando Pereira wrote:
>Senthil_OR at Dell.com escreveu:
>> Okay, I guess, people are missing points here. 
>>  
>> When do you
>>  
>> #!/usr/local/bin/python
>> You are specifying the location to the python executable in your machine, that rest of the script needs to be interpreted with.
>> You are pointing to python is located at /usr/local/bin/python
>>  
>> Consider the possiblities that in a different machine, python may be installed at /usr/bin/python or /bin/python in those cases, the above #! will fail.
>> For those cases, we get to call the env executable with argument which will determine the arguments path by searching in the $PATH and use it correctly.
>>  
>> Thus,
>> #/usr/bin/env python
>> Will figure out the correct location of python ( /usr/bin/python or /bin/python from $PATH) and make that as the interpreter for rest of the script.
>> - ( env is almost always located in /usr/bin/ so one need not worry what is env is not present at /usr/bin)
>>  
...
>I've always used #!/usr/bin/python...
>
>Perhaps I should use the "#!/usr/bin/env python" one.

The case where ``#!/usr/bin/env python'' won't work is where
there are multiple versions of python on the system, and one
wants to run a version that's not first in the PATH.  In that
case one needs to put the full path to the proper executable.

Bill
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