Anyone know this? I've never been able to find an answer.
views:
769answers:
5
+3
A:
It finds 'python' also in /usr/local/bin, ~/bin, /opt/bin, ... or wherever it may hide.
Dirk Eddelbuettel
2009-08-30 02:31:52
thanks! it actually caused a problem for me because, for some reason, env didn't' exist.
Kenneth Reitz
2009-08-30 02:40:11
That's a bit misleading. It's only going to find the first "python" on your current $PATH and Python instances on OS X can be pretty good at hiding. In particular, the standard framework builds from python.org and others have "bin" subdirectories within the framework where "python" and other executables and scripts are stored. It's very easy to end up with multiple instances which may or may not have symlinks to them in the usual places, like /usr/local/bin et al. Managing $PATH on OS X in this case is not as straightforward as on systems without framework-style builds.
Ned Deily
2009-08-30 02:51:41
+2
A:
You may find this post to be of interest: http://mail.python.org/pipermail/python-list/2008-May/661514.html
This may be a better explanation: http://mail.python.org/pipermail/tutor/2007-June/054816.html
James Black
2009-08-30 02:34:02
+16
A:
If you're prone to installing python in various and interesting places on your PATH (as in $PATH in typical Unix shells, %PATH on typical Windows ones), using /usr/bin/env will accomodate your whim (well, in Unix-like environments at least) while going directly to /usr/bin/python won't. But losing control of what version of Python your scripts run under is no unalloyed bargain... if you look at my code you're more likely to see it start with, e.g., #!/usr/local/bin/python2.5 rather than with an open and accepting #!/usr/bin/env python -- assuming the script is important I like to ensure it's run with the specific version I have tested and developed it with, NOT a semi-random one;-).
Alex Martelli
2009-08-30 02:36:51
Of course, you can always use #!/usr/bin/env python2.5 to constrain the set of semi-random choices :=)
Ned Deily
2009-08-30 02:42:34
+1 Great explanation, thanks! I hadn't come across that usage of "env" before...now I have something to add to my scripting bag-of-tricks.
Jim Lewis
2009-08-30 02:56:00
+1 for justification of NOT using "env python". Made me realize that if I want to use "env python", I'd better be coding for the lowest common denominator, since I'd have no control over the version of python the user has first in the PATH.
glenn jackman
2009-08-30 18:47:59
+2
A:
it finds the python executable in your environment and uses that. it's more portable because python may not always be in /usr/bin/python. env is always located in /usr/bin.
Charles Ma
2009-08-30 02:37:13