Find path to currently running file

How can I find the full path to the currently running Python script? That is to say, what do I have to do to achieve this:

$ pwd
/tmp
$ python baz.py
running from /tmp 
file is baz.py

__file__ is NOT what you are looking for. Don't use accidental side-effects

sys.argv[0] is always the path to the script (if in fact a script has been invoked) -- see http://docs.python.org/library/sys.html#sys.argv

__file__ is the path of the currently executing file (script or module). This is accidentally the same as the script if it is accessed from the script! If you want to put useful things like locating resource files relative to the script location into a library, then you must use sys.argv[0].

Example:

C:\junk\so>type \junk\so\scriptpath\script1.py
import sys, os
print "script: sys.argv[0] is", repr(sys.argv[0])
print "script: __file__ is", repr(__file__)
print "script: cwd is", repr(os.getcwd())
import whereutils
whereutils.show_where()

C:\junk\so>type \python26\lib\site-packages\whereutils.py
import sys, os
def show_where():
    print "show_where: sys.argv[0] is", repr(sys.argv[0])
    print "show_where: __file__ is", repr(__file__)
    print "show_where: cwd is", repr(os.getcwd())

C:\junk\so>\python26\python scriptpath\script1.py
script: sys.argv[0] is 'scriptpath\\script1.py'
script: __file__ is 'scriptpath\\script1.py'
script: cwd is 'C:\\junk\\so'
show_where: sys.argv[0] is 'scriptpath\\script1.py'
show_where: __file__ is 'C:\\python26\\lib\\site-packages\\whereutils.pyc'
show_where: cwd is 'C:\\junk\\so'

This will print the directory in which the script lives (as opposed to the working directory):

import os
dirname, filename = os.path.split(os.path.abspath(__file__))
print "running from", dirname
print "file is", filename

Here's how it behaves, when I put it in c:\src:

> cd c:\src
> python so-where.py
running from C:\src
file is so-where.py

> cd c:\
> python src\so-where.py
running from C:\src
file is so-where.py

import sys, os

file = sys.argv[0]
pathname = os.path.dirname(file)
print 'running from %s' % os.path.abspath(pathname)
print 'file is %s' % file

Check os.getcwd() (docs)

The running file is always __file__.

Here's a demo script, named identify.py

print __file__

Here's the results

MacBook-5:Projects slott$ python StackOverflow/identify.py 
StackOverflow/identify.py
MacBook-5:Projects slott$ cd StackOverflow/
MacBook-5:StackOverflow slott$ python identify.py 
identify.py