On 12/13/2012 06:45 PM, Steven D'Aprano wrote:
I understand this is not exactly a Python question, but it may be of
interest to other Python programmers, so I'm asking it here instead of a
more generic Linux group.
I have a Centos system which uses Python 2.4 as the system Python, so I
set an alias for my personal use:
[steve@ando ~]$ which python
alias python='python2.7'
/usr/local/bin/python2.7
When I call "python some_script.py" from the command line, it runs under
Python 2.7 as I expected. So I give the script a hash-bang line:
#!/usr/bin/env python
and run the script directly, but instead of getting Python 2.7, it runs
under Python 2.4 and gives me system errors.
When I run env directly, it ignores my alias:
steve@ando ~]$ /usr/bin/env python -V
Python 2.4.3
What am I doing wrong?
After seeing the lecture on Bad Ideas ... this might backfire on me.... :)
But ... if you really want to make the alias show up in all bash shells,
you can put it in your ~/.bashrc file which is executed every time a
shell is created.
alias python='python2.7'
However, alias expansions do not work in non-interactive shells -- so I
don't think it will launch with the #!/bin/env technique.
OTOH -- Shell functions DO operate in non-interactive mode, so you could
add something like:
function python() {
python3 # whichever version of python you want as default
}
# eof of function example to add to ~/.bashrc
OR............
In a bash shell, you can also do:
function python {
python3 # or 2.7 ...
}
export -f python
And that would give the same effect as an alias, but funtions can be
exported to child processes.
It's your system, and we're adults here -- screw it up however you want to.
Cheers!
--
--Jesus Christ is Lord.
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